Multifunctional fusion polypeptide

Abstract

Provided is a fusion polypeptide. The polypeptide contains a first domain, a second domain and a third domain, wherein the first domain is capable of binding to CD3, the second domain is capable of binding to a tumor-associated antigen (TAA), and the third domain is capable of binding to CD28 and / or CTLA4.

Description

A multifunctional fusion peptide Technical Field

[0001] This invention relates to the field of recombinant antibodies, and more specifically, to a multifunctional specific antibody having a conditionally activated recombinant anti-CD3, anti-tumor-associated antigen (TAA) binding site and a CD86 / CD80 fusion protein. Background Technology

[0002] T lymphocyte activation in vivo requires two signals: the first signal is provided by the interaction between the MHC / antigen peptide complex on APCs (antigen-presenting cells) and the TCR / CD3 complex on T lymphocytes; the second signal, the co-stimulatory signal, is provided by the interaction between co-stimulatory receptors on APCs and co-stimulatory molecules on T lymphocytes. Normally, T lymphocytes are only fully activated upon the presence of the first signal (Baxter & Hodgkin, 2002; Bernard et al., 2002).

[0003] There are two types of T lymphocytes: cytotoxic T lymphocytes (CTLs) and T helper cells (THs). CTLs are the main effector cells in cell-mediated immune responses, while THs indirectly participate in cell-mediated immune responses by secreting cytokines (such as interleukin-2 (IL-2)). Since tumor immunity is mainly cell-mediated, designing anti-tumor drugs that specifically activate CTLs is of great significance in tumor immunotherapy (Foss, 2002).

[0004] Because CD3 is closely related to T cell activation, the use of bispecific antibodies against human CD3 and tumor-associated antigens (TAAs) for anti-tumor therapy has been extensively studied. CD3 and TAA bispecific antibodies are also known as Bispecific T-cell engagers (BiTEs). The two arms of the CD3 and TAA bispecific antibody target the T cell surface antigen CD3 and the tumor cell surface antigen TAA, respectively, thereby bridging the gap between tumor cells and effector T cells. This bypasses the classic activation pathway where T cells must form a complex with the MHC antigen peptide and the TCR, as well as bind to co-stimulatory molecules, before activation. Activated T cells release granzymes and perforin, effectively killing tumor cells.

[0005] Currently, a series of recombinant CD3 and TAA bispecific antibodies (BsAbs) have been developed to provide the first signal for CTL activation. Some of these have already been approved by the FDA, such as Catumaxomab (CD3xEpCAM), Blinatumomab (CD3xCD19), and Tebentafusp (CD3xIMCgp100). More than 100 bispecific antibodies are in clinical trials. TAAs include, but are not limited to, CD19, CD20, CD38, DLL3, EGFR, FLT3, STEAP1, MUC16, MUC17, PD1, PDL1, GPRC5D, BCMA, PSCA, CTLA-4, VEGF, PRAME, 5T4, and GCC (Wei et al., 2022). In summary, CD3 and TAA bispecific antibodies have been shown to specifically activate T lymphocytes via CD3 and significantly induce tumor-specific cell lysis, but there are still some gaps compared to CAR-T cell therapy. Since they do not provide co-stimulatory signals, most of them cannot fully activate T lymphocytes and may lead to activation-induced cell death (AICD) of T lymphocytes (Daniel et al., 1998) and reduce their tumor-specific cell lysis (Daniel et al., 1998).

[0006] The clinical application of bispecific T-cell connectors (TCEs) in the treatment of solid tumors is limited by "on-target, off-tumor toxicity," which restricts the expansion of the therapeutic window. It is necessary to reduce the toxicity of such treatments and improve efficacy to broaden the therapeutic window. Janux's protease-activated TCE (PSMAxCD3-TRACTr) uses a special peptide to mask the binding of CD3 antibodies and has demonstrated good efficacy and safety in clinical trials. However, many other TCEs with CD3 antibody-masking capabilities have limited efficacy. This may be related to inappropriate CD3 antibody-masking activity, relatively simple enzymatic activation conditions, and weaker TCE function. Summary of the Invention

[0007] To overcome the aforementioned shortcomings, this invention proposes the development of a multifunctional fusion peptide that provides co-stimulatory signals and conditional activation. Based on a CD3 and TAA bispecific antibody, it provides dual activation signals for CTLs, enabling simultaneous interaction with multiple sites on both target and effector cells, and inducing more effective tumor-specific cell lysis. CD28 is one such co-stimulatory signal. This multifunctional fusion peptide, possessing three binding specificities (targeting TAA, CD3, and CD28), provides dual activation signals within a single molecule. By binding to the CD3 and CD28 effector sites on T lymphocytes, it recruits and stimulates effector T cells through dual signaling pathway activation, enhancing their ability to recognize and eliminate tumor cells. Simultaneously, the safety of the multifunctional fusion peptide is improved by masking the CD3 binding site.

[0008] Specifically, the present invention provides a fusion polypeptide comprising a first domain, a second domain and a third domain, wherein the first domain is capable of binding CD3, the second domain is capable of binding tumor-associated antigen (TAA), and the third domain is capable of binding CD28 and / or CTLA4.

[0009] In some implementations, the first domain comprises an antibody or an antigen-binding fragment thereof.

[0010] In some embodiments, the first domain antibody is selected from the group consisting of recombinant antibodies, single-domain antibodies, heavy chain antibodies, chimeric antibodies, and bispecific antibodies.

[0011] In some embodiments, the first domain antigen-binding fragment is selected from one or more fragments from the group consisting of: Fab, Fab', Fv fragment, F(ab')2, F(ab)2, scFv, di-scFv, VHH, and dAb.

[0012] In some embodiments, the first domain comprises an antibody, its antigen-binding fragment, or a variant thereof selected from the group consisting of: antibody OKT3, antibody UCHT1, antibody SP34, Blinatumamab, Tebentafusp, Mosunetuzumab, and Teclistamab.

[0013] In some embodiments, the first domain comprises an antibody SP34 mutant or its antigen-binding site.

[0014] In some embodiments, the first domain may include an antibody SP34 mutant or its antigen-binding site, wherein the mutation occurs in the CDR region.

[0015] In some embodiments, the mutation occurs in the HCDR region, and the mutation comprises one or more amino acid site mutations selected from the group shown in SEQ ID NO:22 of the antibody SP34 heavy chain variable region: T31D, R50K, N100D, N97S, F100fH, S100aA, V100cT.

[0016] In some embodiments, the mutation occurs in the LCDR region and comprises one or more amino acid site mutations selected from the group shown in SEQ ID NO:12 of antibody SP34 light chain variable region: N94Q.

[0017] In some embodiments, the first domain comprises a single-chain immunoglobulin domain.

[0018] In some embodiments, the first domain comprises a single-chain immunoglobulin IgG antibody.

[0019] In some embodiments, the single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

[0020] In some embodiments, the first domain comprises a single-chain immunoglobulin Fc domain.

[0021] In some embodiments, the first domain comprises the Fc domain of a single-chain immunoglobulin IgG antibody.

[0022] In some embodiments, the Fc domain of the single-chain immunoglobulin IgG antibody includes human IgG1 Fc domain, human IgG2 Fc domain, human IgG3 Fc domain, human IgG4 Fc domain, mouse IgG1 Fc domain, mouse IgG2a Fc domain, mouse IgG2b Fc domain, or mouse IgG3 Fc domain.

[0023] The first domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences, wherein the first domain CH2 is located between the variable region and the CH3 domain; preferably, the Fc fragment contains any amino acid sequence selected from the group consisting of: SEQ ID NO: 3, SEQ ID NO: 4.

[0024] In some embodiments, the first domain includes a heavy chain variable region, wherein the HCDR1, HCDR2, and / or HCDR3 amino acid sequences or variant sequences thereof of the heavy chain variable region are selected from any one of the following amino acid sequences: SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 302, SEQ ID NO: 303, SEQ ID NO: 304, SEQ ID NO: 307, SEQ ID NO: 308, SEQ ID NO: 309, SEQ ID NO: 312, SEQ ID NO: 313, SEQ ID NO: 314, SEQ ID NO: 317, SEQ ID NO: 318, SEQ ID NO: 319, SEQ ID NO: 327, SEQ ID NO: 32 ... SEQ ID NO: 329, SEQ ID NO: 337, SEQ ID NO: 338, SEQ ID NO: 339; wherein, the first structural domain optionally further includes a light chain variable region, wherein the LCDR1, LCDR2 and / or LCDR3 amino acid sequences or variant sequences thereof of the light chain variable region of the first structural domain contain any one of the following amino acid sequences: SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 323, SEQ ID NO: 324, SEQ ID NO: 325, SEQ ID NO: 333, SEQ ID NO: 334, SEQ ID NO: 335.

[0025] In some embodiments, the first domain includes a heavy chain variable region VH of the antibody heavy chain, said VH comprising an amino acid sequence selected from any of the following groups: SEQ ID NO: 22, SEQ ID NO: 27, SEQ ID NO: 32, SEQ ID NO: 42, SEQ ID NO: 301, SEQ ID NO: 306, SEQ ID NO: 311, SEQ ID NO: 316, SEQ ID NO: 326, SEQ ID NO: 336.

[0026] In some embodiments, the first domain comprises an antibody heavy chain comprising any amino acid sequence selected from the group consisting of: SEQ ID NO: 21, SEQ ID NO: 26, SEQ ID NO: 31, SEQ ID NO: 36, SEQ ID NO: 300, SEQ ID NO: 305, SEQ ID NO: 310, SEQ ID NO: 315, SEQ ID NO: 320, SEQ ID NO: 330.

[0027] In some embodiments, the first domain includes a light chain variable region VL of the antibody light chain, the VL comprising any amino acid sequence selected from the group consisting of: SEQ ID NO: 12, SEQ ID NO: 17, SEQ ID NO: 38, SEQ ID NO: 322, SEQ ID NO: 332.

[0028] In some embodiments, the first domain comprises an antibody light chain, the antibody light chain comprising any one of the amino acid sequences selected from the group consisting of: SEQ ID NO: 11, SEQ ID NO: 16.

[0029] In some embodiments, the first domain may include HCDR1, HCDR2, and HCDR3 of the antibody heavy chain, wherein:

[0030] The HCDR1, HCDR2, and HCDR3 may respectively contain the amino acid sequences shown in SEQ ID NO: 23, SEQ ID NO: 24, and SEQ ID NO: 25; or may respectively contain the amino acid sequences shown in SEQ ID NO: 28, SEQ ID NO: 29, and SEQ ID NO: 30; or may respectively contain the amino acid sequences shown in SEQ ID NO: 33, SEQ ID NO: 34, and SEQ ID NO: 35; or may respectively contain the amino acid sequences shown in SEQ ID NO: 43, SEQ ID NO: 44, and SEQ ID NO: 45; or may respectively contain the amino acid sequences shown in SEQ ID NO: 302, SEQ ID NO: 303, and SEQ ID NO: 304; or may respectively contain the amino acid sequences shown in SEQ ID NO: 307, SEQ ID NO: 308, and SEQ ID NO: 309; or may respectively contain the amino acid sequences shown in SEQ ID NO: 312, SEQ ID NO: 313, and SEQ ID NO: 314; or may respectively contain the amino acid sequences shown in SEQ ID NO: 317, SEQ ID NO: 318, and SEQ ID NO: 31 ...9; or may respectively contain the amino acid sequences shown in SEQ ID NO: 312, SEQ ID NO: 313, and SEQ ID NO: 319; or may respectively contain the amino acid sequences shown in SEQ ID NO: The amino acid sequence shown in NO: 319 may be included; or may contain amino acid sequences as shown in SEQ ID NO: 327, SEQ ID NO: 328, SEQ ID NO: 329 respectively; or may contain amino acid sequences as shown in SEQ ID NO: 337, SEQ ID NO: 338, SEQ ID NO: 339 respectively.

[0031] In some embodiments, the first domain may comprise LCDR1, LCDR2, and LCDR3 of the antibody light chain, wherein:

[0032] The LCDR1, LCDR2, and LCDR3 may each contain the amino acid sequences shown in SEQ ID NO: 13, SEQ ID NO: 14, and SEQ ID NO: 15; or may each contain the amino acid sequences shown in SEQ ID NO: 18, SEQ ID NO: 19, and SEQ ID NO: 20; or may each contain the amino acid sequences shown in SEQ ID NO: 39, SEQ ID NO: 40, and SEQ ID NO: 41; or may each contain the amino acid sequences shown in SEQ ID NO: 323, SEQ ID NO: 324, and SEQ ID NO: 325; or may each contain the amino acid sequences shown in SEQ ID NO: 333, SEQ ID NO: 334, and SEQ ID NO: 335.

[0033] In some implementations, the first domain does not contain light chains.

[0034] In some implementations, the first domain does not include the CH1 domain.

[0035] In some implementations, the second domain is capable of binding tumor-associated antigens (TAAs).

[0036] In some embodiments, the second domain is capable of binding to proteins or tumor antigens that are overexpressed on tumor cells relative to the corresponding non-tumor cells.

[0037] In some embodiments, the second domain comprises an antibody or an antigen-binding fragment thereof.

[0038] In some embodiments, the second domain antibody is selected from the group consisting of recombinant antibodies, single-domain antibodies, heavy chain antibodies, chimeric antibodies, and bispecific antibodies.

[0039] In some embodiments, the second domain antigen-binding fragment is selected from one or more fragments from the group consisting of: Fab, Fab', Fv fragment, F(ab')2, F(ab)2, scFv, di-scFv, VHH, and dAb.

[0040] In some embodiments, the second domain can bind to one or more of the targets shown in the following group: PD-L1, PD-L2, VEGF, VEGFR, FGFR, HER2, HGFR, PIP-LAR, CD44, CD147, TfR, CDCP1, α6β4, α6β3, Trop2, HHLA2, GCC, 5T4, EpCAM, GPRC5D, BCMA, CD19, CD20, HER-2neu, DLL1, DLL3, B7H3, HER-3, HER-4, EGFR, PSMA, CEA, MUC-1 (mucin), MUC2, MUC3, MUC4, MUC5AC, MUC5B, MUC7, CD123, CD33, CD30, CD38, PTK7, EphA2, NKG2A, Nkp36, Tim3, CD20, Her2.

[0041] In some embodiments, the second domain comprises a single-chain immunoglobulin domain.

[0042] In some embodiments, the second domain comprises a single-chain immunoglobulin IgG antibody.

[0043] In some embodiments, the second domain single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

[0044] In some embodiments, the second domain comprises a single-chain immunoglobulin Fc domain.

[0045] In some embodiments, the second domain comprises the Fc domain of a single-chain immunoglobulin IgG antibody.

[0046] In some embodiments, the Fc domain of the single-chain immunoglobulin IgG antibody includes human IgG1 Fc domain, human IgG2 Fc domain, human IgG3 Fc domain, human IgG4 Fc domain, mouse IgG1 Fc domain, mouse IgG2a Fc domain, mouse IgG2b Fc domain, or mouse IgG3 Fc domain.

[0047] In some embodiments, the second domain single-stranded immunoglobulin Fc fragment comprises CH2 and / or CH3 sequences, with the second domain CH2 located between the variable region and the CH3 domain; preferably, the Fc fragment comprises any amino acid sequence selected from the group consisting of SEQ ID NO: 3 and SEQ ID NO: 4.

[0048] In some embodiments, the HCDR1, HCDR2, and / or HCDR3 amino acid sequences or variant sequences thereof in the heavy chain variable region comprise any one of the amino acid sequences selected from the group consisting of: SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 64, SEQ ID NO: 65, SEQ ID NO: 66, SEQ ID NO: 69, SEQ ID NO: 70, SEQ ID NO: 71, SEQ ID NO: 74, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 79, SEQ ID NO: 80, SEQ ID NO: 81, SEQ ID NO: 84, SEQ ID NO: 85, SEQ ID NO: 86, SEQ ID NO: 94, SEQ ID NO: 95, SEQ ID NO: 96, SEQ ID NO: 1002, SEQ ID NO: 1003, SEQ ID NO: 1004, SEQ ID NO: 1011, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 64, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 79, SEQ ID NO: 80, SEQ ID NO: 81, SEQ ID NO: 84, SEQ ID NO: 85, SEQ ID NO: 86, SEQ ID NO: 94, SEQ ID NO: 95, SEQ ID NO: 96, SEQ ID NO: 1002, SEQ ID NO: 1003, SEQ ID NO: 1004, SEQ ID NO: 1011, SEQ ID NO SEQ ID NO: 1012, SEQ ID NO: 1013, SEQ ID NO: 2007, SEQ ID NO: 2008, SEQ ID NO: 2009, SEQ ID NO: 2012, SEQ ID NO: 2013, SEQ ID NO: 2014; the light chain variable region's LCDR1, LCDR2 and / or LCDR3 amino acid sequences or variant sequences thereof, comprising any amino acid sequence selected from the following group: SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 89, SEQ ID NO: 90, SEQ ID NO: 91, SEQ ID NO: 1015, SEQ ID NO: 1016, SEQ ID NO: 1017, SEQ ID NO: 2003, SEQ ID NO: 2004, SEQ ID NO: 2005.

[0049] In some embodiments, the second structure includes a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain variable region VH comprising any amino acid sequence selected from the group consisting of: SEQ ID NO: 47, SEQ ID NO: 58, SEQ ID NO: 63, SEQ ID NO: 68, SEQ ID NO: 73, SEQ ID NO: 78, SEQ ID NO: 83, SEQ ID NO: 93, SEQ ID NO: 1001, SEQ ID NO: 1010, SEQ ID NO: 2006, SEQ ID NO: 2011.

[0050] In some embodiments, the second structure comprises an antibody heavy chain comprising an amino acid sequence selected from the group consisting of: SEQ ID NO: 46, SEQ ID NO: 57, SEQ ID NO: 62, SEQ ID NO: 67, SEQ ID NO: 72, SEQ ID NO: 77, SEQ ID NO: 82, SEQ ID NO: 92, SEQ ID NO: 1000, SEQ ID NO: 1005, SEQ ID NO: 1018, SEQ ID NO: 2000, SEQ ID NO: 2010.

[0051] In some embodiments, the second structure includes a light chain variable region VL of an antibody light chain, the antibody light chain comprising any amino acid sequence selected from the group consisting of: SEQ ID NO: 53, SEQ ID NO: 88, SEQ ID NO: 1014, SEQ ID NO: 2002.

[0052] In some embodiments, the second domain comprises an antibody light chain containing an amino acid sequence selected from the group consisting of SEQ ID NO: 52 and SEQ ID NO: 87.

[0053] In some embodiments, the second domain may comprise HCDR1, HCDR2, and HCDR3 of the antibody heavy chain, and LCDR1, LCDR2, and LCDR3 of the antibody light chain, wherein HCDR1, HCDR2, and HCDR3 may each comprise amino acid sequences as shown in SEQ ID NO: 59, SEQ ID NO: 60, and SEQ ID NO: 61, and LCDR1, LCDR2, and LCDR3 may each comprise amino acid sequences as shown in SEQ ID NO: 54, SEQ ID NO: 55, and SEQ ID NO: 56, respectively.

[0054] In some embodiments, the second domain may include a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain VH may include an amino acid sequence as shown in SEQ ID NO: 58, and the second domain may include a light chain variable region VL of the antibody light chain, the antibody light chain VL may include an amino acid sequence as shown in SEQ ID NO: 53.

[0055] In some embodiments, the second domain may comprise an antibody heavy chain and / or an antibody light chain, wherein the antibody heavy chain may comprise an amino acid sequence as shown in SEQ ID NO: 57, and the antibody light chain may comprise an amino acid sequence as shown in SEQ ID NO: 52.

[0056] In some embodiments, the second domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 48, SEQ ID NO: 49, and SEQ ID NO: 50, respectively.

[0057] In some embodiments, the second domain may comprise the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may comprise an amino acid sequence as shown in SEQ ID NO: 47.

[0058] In some embodiments, the second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 46.

[0059] In some embodiments, the second domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 64, SEQ ID NO: 65, and SEQ ID NO: 66, respectively.

[0060] In some embodiments, the second domain may include the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO: 63.

[0061] In some embodiments, the second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 62.

[0062] In some embodiments, the second domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 69, SEQ ID NO: 70, and SEQ ID NO: 71, respectively.

[0063] In some embodiments, the second domain may comprise the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may comprise an amino acid sequence as shown in SEQ ID NO: 68.

[0064] In some embodiments, the second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 67.

[0065] In some embodiments, the second domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 74, SEQ ID NO: 75, and SEQ ID NO: 76, respectively.

[0066] In some embodiments, the second domain may comprise the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may comprise an amino acid sequence as shown in SEQ ID NO: 73.

[0067] In some embodiments, the second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 72.

[0068] In some embodiments, the second domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 79, SEQ ID NO: 80, and SEQ ID NO: 81, respectively.

[0069] In some embodiments, the second domain may include the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO: 78.

[0070] In some embodiments, the second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 77.

[0071] In some embodiments, the second domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 84, SEQ ID NO: 85, and SEQ ID NO: 86, respectively.

[0072] In some embodiments, the second domain may include the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO: 83.

[0073] In some embodiments, the second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 82.

[0074] In some embodiments, the second domain may comprise HCDR1, HCDR2, and HCDR3 of the antibody heavy chain, and LCDR1, LCDR2, and LCDR3 of the antibody light chain, wherein HCDR1, HCDR2, and HCDR3 may each comprise amino acid sequences as shown in SEQ ID NO: 94, SEQ ID NO: 95, and SEQ ID NO: 96, and LCDR1, LCDR2, and LCDR3 may each comprise amino acid sequences as shown in SEQ ID NO: 89, SEQ ID NO: 90, and SEQ ID NO: 91, respectively.

[0075] In some embodiments, the second domain may include a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain VH may include an amino acid sequence as shown in SEQ ID NO: 93, and the second domain may include a light chain variable region VL of the antibody light chain, the antibody light chain VL may include an amino acid sequence as shown in SEQ ID NO: 88.

[0076] In some embodiments, the second domain may comprise an antibody heavy chain and / or an antibody light chain, wherein the antibody heavy chain may comprise an amino acid sequence as shown in SEQ ID NO: 92, and the antibody light chain may comprise an amino acid sequence as shown in SEQ ID NO: 87.

[0077] In some embodiments, the second domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 1002, SEQ ID NO: 1003, and SEQ ID NO: 1004, respectively.

[0078] In some embodiments, the second domain may comprise the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may comprise an amino acid sequence as shown in SEQ ID NO: 1001.

[0079] In some embodiments, the second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 1000 or SEQ ID NO: 1005.

[0080] In some embodiments, the second domain may comprise the heavy chains HCDR1, HCDR2, and HCDR3 and the light chains LCDR1, LCDR2, and LCDR3 of the scFv antibody, wherein HCDR1, HCDR2, and HCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 1011, SEQ ID NO: 1012, and SEQ ID NO: 1013, respectively, and LDR1, LCDR2, and LCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 1015, SEQ ID NO: 1016, and SEQ ID NO: 1017, respectively.

[0081] In some embodiments, the second domain may comprise a heavy chain variable region VH and a light chain variable region VL of the scFv antibody, wherein the VH may comprise an amino acid sequence as shown in SEQ ID NO: 1010, and the VL may comprise an amino acid sequence as shown in SEQ ID NO: 1014.

[0082] In some embodiments, the second domain may contain an scFv antibody, which may contain an amino acid sequence as shown in SEQ ID NO: 1009 or SEQ ID NO: 1018.

[0083] In some embodiments, the second domain may comprise the heavy chains HCDR1, HCDR2, and HCDR3 and the light chains LCDR1, LCDR2, and LCDR3 of the scFv antibody, wherein HCDR1, HCDR2, and HCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 2007, SEQ ID NO: 2008, and SEQ ID NO: 2009, respectively, and LDR1, LCDR2, and LCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 2003, SEQ ID NO: 2004, and SEQ ID NO: 2005, respectively.

[0084] In some embodiments, the second domain may comprise a heavy chain variable region VH and a light chain variable region VL of the scFv antibody, wherein the VH may comprise an amino acid sequence as shown in SEQ ID NO: 2006, and the VL may comprise an amino acid sequence as shown in SEQ ID NO: 2002.

[0085] In some embodiments, the second domain may contain an scFv antibody, which may contain an amino acid sequence as shown in SEQ ID NO: 2001 or SEQ ID NO: 2000.

[0086] In some embodiments, the second domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 2012, SEQ ID NO: 2013, and SEQ ID NO: 2014, respectively.

[0087] In some embodiments, the second domain may comprise the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may comprise an amino acid sequence as shown in SEQ ID NO: 2011.

[0088] In some embodiments, the second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 2010.

[0089] In some implementations, the second structural domain does not contain light chains.

[0090] In some embodiments, the second domain fusion peptide described above does not contain a CH1 domain.

[0091] In some implementations, the third domain can be combined with CD28 and / or CTLA4.

[0092] In some embodiments, the third domain comprises CD86 or CD80 or their functionally active fragments, or variations thereof.

[0093] In some embodiments, the third domain is selected from the group consisting of CD86 or CD80 derived from humans or mice, or functionally active fragments thereof or variants thereof.

[0094] In some embodiments, the third domain comprises the extracellular domain of CD86 or CD80, or a functionally active fragment thereof, or a variant thereof.

[0095] In some embodiments, the third domain comprises the IgV of CD86 or CD80, or a functionally active fragment thereof, or a variant thereof.

[0096] In some embodiments, the third domain comprises a CD86 variant polypeptide, wherein the mutant comprises an amino acid substitution mutation of human CD86.

[0097] In some embodiments, the third domain comprises a CD86 variant polypeptide comprising an IgV domain amino acid substitution mutant of CD86 and / or an extracellular domain amino acid substitution mutant of human CD86.

[0098] In some embodiments, the third domain comprises a CD86 variant polypeptide, the CD86 variant polypeptide comprising an IgV domain amino acid substitution mutant of CD86, the mutation site of the CD86 IgV domain amino acid substitution mutant comprising one, two, three, four, five or more amino acid site mutations selected from the group consisting of: A13I, A13L, A13F, A13M, Q25A, Q25I, Q25V, Q25F, Q25M, F33A, F33L, F33V, F33M, M60R, I89A, I89L, I89V, I89F, I89M, H90I, H90V, H90M, H90F.

[0099] In some embodiments, the third domain comprises a CD86 variant polypeptide comprising an IgV domain amino acid substitution mutant of CD86, the amino acid substitution mutant comprising combinations shown below: Q25I / F33L / H90I, Q25V / F33L / H90I, Q25I / F33V / H90I, Q25V / F33V / H90I, Q25I / F33L / H90V, Q25 V / F33L / H90V, Q25I / F33V / H90V, Q25V / F33V / H90V, A13L / Q25I / F33L / H90I, A13I / Q25I / F33L / H 90I, A13L / Q25V / F33L / H90I, A13I / Q25V / F33L / H90I, Q25I / F33L / I89L / H90I, Q25I / F33L / M60R / H90I、Q25V / F33L / I89L / H90I、Q25V / F33L / M60R / H90I、Q25F / F33L / H90I、Q25I / F33L / H90F、Q 25I / F33A / H90I, Q25I / H90I, Q25I, H90I, Q25V / H90V, Q25V / H90I, Q25F / H90I, Q25F / H90V, A13F / Q25I / F33L / H90I, A13M / Q25I / F33L / H90I, Q25A / F33L / H90I, Q25M / F33L / H90I, Q25I / F33M / H90I, Q25I / F33L / I89V / H90I, Q25I / F33L / I89F / H90I, Q25I / F33L / I89M / H90I and Q25I / F33L / H90M.

[0100] In some embodiments, the third domain comprises a CD86 variant polypeptide containing the IgV domain amino acid substitution mutant Q25I / F33L / H90I of CD86.

[0101] In some embodiments, the third domain comprises a CD86 variant polypeptide, the CD86 variant polypeptide comprising an extracellular domain amino acid substitution mutant of CD86, the extracellular domain amino acid substitution mutant of CD86 comprising one, two, three, four, five or more amino acid site mutations selected from the group consisting of: A13I, A13L, A13F, A13M, Q25A, Q25I, Q25V, Q25F, Q25M, F33A, F33L, F33V, F33M, M60R, I89A, I89L, I89V, I89F, I89M, H90I, H90V, H90M, H90F.

[0102] In some embodiments, the third domain comprises an extracellular domain amino acid substitution mutant of CD86, the amino acid substitution mutant comprising combinations shown below: Q25I / F33L / H90I, Q25V / F33L / H90I, Q25I / F33V / H90I, Q25V / F33V / H90I, Q25I / F33L / H90V, Q25V / F33L / H90V, Q25 I / F33V / H90V, Q25V / F33V / H90V, A13L / Q25I / F33L / H90I, A13I / Q25I / F33L / H90I, A13L / Q25 V / F33L / H90I, A13I / Q25V / F33L / H90I, Q25I / F33L / I89L / H90I, Q25I / F33L / M60R / H90I, Q25V / F33L / I89L / H90I, Q25V / F33L / M60R / H90I, Q25F / F33L / H90I, Q25I / F33L / H90F, Q25I / F33A / H90I, Q25I / H90I, Q25I, H90I, Q25V / H90V, Q25V / H90I, Q25F / H90I, Q25F / H90V, A13F / Q25I / F33L / H90I, A13M / Q25I / F33L / H90I, Q25A / F33L / H90I, Q25M / F33L / H90I, Q25I / F33M / H90I, Q25I / F33L / I89V / H90I, Q25I / F33L / I89F / H90I, Q25I / F33L / I89M / H90I and Q25I / F33L / H90M.

[0103] In some embodiments, the third domain comprises an extracellular domain amino acid substitution mutant of CD86, the amino acid substitution mutant comprising the combination shown below: Q25I / F33L / H90I.

[0104] In some embodiments, the third domain comprises an amino acid sequence selected from SEQ ID NO: 97 to SEQ ID NO: 165.

[0105] In some embodiments, the third domain comprises a CD80 variant polypeptide, wherein the mutant comprises an amino acid substitution mutation of human CD80.

[0106] In some embodiments, the third domain comprises a CD80 variant polypeptide, which comprises an IgV domain amino acid substitution mutant of CD80 and / or an extracellular domain amino acid substitution mutant of human CD80.

[0107] In some implementations, the first domain is directly or indirectly connected to the second domain.

[0108] In some implementations, the heavy chain Fc of the first structural domain is directly or indirectly connected to the heavy chain Fc of the second structural domain.

[0109] In some embodiments, the heavy chain Fc segment of the first structural domain is linked to the heavy chain Fc of the second structural domain via disulfide bonds.

[0110] In some embodiments, the heavy chain of the first structural domain forms a heterodimer with the heavy chain of the second structural domain.

[0111] In some implementations, the heavy chain Fc segments of the first structural domain and the heavy chain Fc segments of the second structural domain are connected by a knobs-into-holes structure.

[0112] In some implementations, knots-into-holes pairing is achieved by including one or more substitutions in the Fc segment of the heavy chain, which form heterodimeric pairings between the two heavy chains.

[0113] In some implementations, CH3 in the first domain and CH3 in the second domain are substitution pairs in a pestle-mortar structure.

[0114] In some embodiments, the T366 and / or Y407 amino acid residues on one of the CH3 domains of the first and second domains are replaced, and the L368 amino acid residue on the other CH3 domain is replaced.

[0115] In some embodiments, T366 is replaced with tyrosine (Y) or tryptophan (W); and / or Y407 is replaced with threonine (T), alanine (A) or valine (V); and / or L368 is replaced with alanine (A).

[0116] In some implementations, the antigen-binding fragment of the first domain is directly or indirectly linked to the second domain.

[0117] In some embodiments, the N-terminus of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the second domain; or the C-terminus of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the second domain.

[0118] In some embodiments, the heavy chain of the first domain antigen-binding fragment is directly or indirectly linked to the heavy chain of the second domain; or the light chain of the first domain antigen-binding fragment is directly or indirectly linked to the heavy chain of the second domain; or the heavy chain of the first domain antigen-binding fragment is directly or indirectly linked to the light chain of the second domain; or the light chain of the first domain antigen-binding fragment is directly or indirectly linked to the light chain of the second domain.

[0119] In some embodiments, the C-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the second domain; or the C-terminus of the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the second domain; or the C-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the second domain; or the N-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the second domain; or the N-terminus of the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the second domain; or the N-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the second domain; or the N-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the second domain; or the N-terminus of the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the second domain.

[0120] In some implementations, the first domain is directly or indirectly linked to the antigen-binding fragment of the second domain.

[0121] In some embodiments, the N-terminus of the first domain is directly or indirectly connected to the C-terminus of the antigen-binding fragment of the second domain; or the C-terminus of the first domain is directly or indirectly connected to the N-terminus of the antigen-binding fragment of the second domain.

[0122] In some embodiments, the heavy chain of the first domain is directly or indirectly linked to the heavy chain of the antigen-binding fragment of the second domain; or the light chain of the first domain is directly or indirectly linked to the heavy chain of the antigen-binding fragment of the second domain; or the heavy chain of the first domain is directly or indirectly linked to the light chain of the antigen-binding fragment of the second domain; or the light chain of the first domain is directly or indirectly linked to the light chain of the antigen-binding fragment of the second domain.

[0123] In some embodiments, the C-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the first domain; or the C-terminus of the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the first domain; or the C-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the first domain; or the N-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the first domain; or the N-terminus of the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the first domain; or the N-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the first domain; or the N-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the first domain; or the N-terminus of the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the first domain.

[0124] In some implementations, the first domain and the third domain are directly or indirectly connected.

[0125] In some implementations, the first domain heavy chain is directly or indirectly connected to the third domain. For example, the C-terminus of the first domain heavy chain is directly or indirectly connected to the N-terminus of the third domain, or the N-terminus of the first domain heavy chain is directly or indirectly connected to the C-terminus of the third domain.

[0126] In some implementations, the first structural domain light chain is directly or indirectly connected to the third structural domain. For example, the C-terminus of the first structural domain light chain is directly or indirectly connected to the N-terminus of the third structural domain, or the N-terminus of the first structural domain light chain is directly or indirectly connected to the C-terminus of the third structural domain.

[0127] In some implementations, the second and third domains are directly or indirectly connected.

[0128] In some implementations, the second domain heavy chain is directly or indirectly connected to the third domain. For example, the C-end of the second domain heavy chain is directly or indirectly connected to the N-end of the third domain, or the N-end of the second domain heavy chain is directly or indirectly connected to the C-end of the third domain.

[0129] In some embodiments, the second structural domain light chain is directly or indirectly connected to the third structural domain. For example, the C-terminus of the second structural domain light chain is directly or indirectly connected to the N-terminus of the third structural domain, or the N-terminus of the second structural domain light chain is directly or indirectly connected to the C-terminus of the third structural domain.

[0130] In some embodiments, the N-terminus of the first structural domain is directly or indirectly connected to the C-terminus of the third structural domain, and the second structural domain is not directly or indirectly connected to the third structural domain; or the C-terminus of the first structural domain is directly or indirectly connected to the N-terminus of the third structural domain, and the second structural domain is not directly or indirectly connected to the third structural domain; or the N-terminus of the second structural domain is directly or indirectly connected to the C-terminus of the third structural domain, and the first structural domain is not directly or indirectly connected to the third structural domain; or the C-terminus of the second structural domain is directly or indirectly connected to the N-terminus of the third structural domain, and the first structural domain is not directly or indirectly connected to the third structural domain.

[0131] In some implementations, the first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain.

[0132] In some implementations, the heavy chain of the first structural domain is directly or indirectly connected to the heavy chain of the second structural domain; and the first structural domain is directly or indirectly connected to the third structural domain.

[0133] In some implementations, the C-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the N-terminus of the heavy chain of the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain.

[0134] In some embodiments, the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain.

[0135] In some embodiments, the N-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the C-terminus of the heavy chain of the second structural domain, and the first structure is directly or indirectly connected to the third structural domain.

[0136] In some embodiments, the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain.

[0137] In some embodiments, the heavy chain of the first structural domain is directly or indirectly connected to the light chain of the second structural domain; and the first structural domain is directly or indirectly connected to the third structural domain.

[0138] In some embodiments, the C-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the N-terminus of the light chain of the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain.

[0139] In some embodiments, the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain.

[0140] In some embodiments, the N-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the C-terminus of the light chain of the second structural domain, and the first structure is directly or indirectly connected to the third structural domain.

[0141] In some embodiments, the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain.

[0142] In some embodiments, the light chain of the first structural domain is directly or indirectly connected to the heavy chain of the second structural domain; and the first structural domain is directly or indirectly connected to the third structural domain.

[0143] In some embodiments, the C-terminus of the light chain of the first structural domain is directly or indirectly connected to the N-terminus of the heavy chain of the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain.

[0144] In some embodiments, the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain.

[0145] In some embodiments, the N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the heavy chain of the second structural domain, and the first structure is directly or indirectly connected to the third structural domain.

[0146] In some embodiments, the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain.

[0147] In some embodiments, the light chain of the first structural domain is directly or indirectly connected to the light chain of the second structural domain; and the first structural domain is directly or indirectly connected to the third structural domain.

[0148] In some embodiments, the C-terminus of the light chain of the first structural domain is directly or indirectly connected to the N-terminus of the light chain of the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain.

[0149] In some embodiments, the C-terminus of the light chain of the first structural domain is directly or indirectly connected to the N-terminus of the light chain of the second structural domain, and the N-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the C-terminus of the third structural domain; or the C-terminus of the light chain of the first structural domain is directly or indirectly connected to the N-terminus of the light chain of the second structural domain, and the N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the third structural domain; or the C-terminus of the light chain of the first structural domain is directly or indirectly connected to the N-terminus of the light chain of the second structural domain, and the C-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the N-terminus of the third structural domain.

[0150] In some embodiments, the N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the light chain of the second structural domain, and the first structure is directly or indirectly connected to the third structural domain.

[0151] In some embodiments, the N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the light chain of the second structural domain, and the C-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the N-terminus of the third structural domain; or the N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the light chain of the second structural domain, and the C-terminus of the light chain of the first structural domain is directly or indirectly connected to the N-terminus of the third structural domain; or the N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the light chain of the second structural domain, and the N-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the C-terminus of the third structural domain.

[0152] In some implementations, the first structural domain is directly or indirectly connected to the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0153] In some implementations, the heavy chain of the first structural domain is directly or indirectly connected to the heavy chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0154] In some embodiments, the N-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the C-terminus of the heavy chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0155] In some embodiments, the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the N-end of the heavy chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain.

[0156] In some implementations, the C-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the N-terminus of the heavy chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0157] In some embodiments, the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain.

[0158] In some embodiments, the heavy chain of the first structural domain is directly or indirectly connected to the light chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0159] In some embodiments, the N-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the C-terminus of the light chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0160] In some embodiments, the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the N-end of the heavy chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain.

[0161] In some embodiments, the C-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the N-terminus of the light chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0162] In some embodiments, the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the N-end of the heavy chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain.

[0163] In some embodiments, the light chain of the first structural domain is directly or indirectly connected to the heavy chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0164] In some embodiments, the N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the heavy chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0165] In some embodiments, the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the N-end of the heavy chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain.

[0166] In some embodiments, the C-terminus of the light chain of the first structural domain is directly or indirectly connected to the N-terminus of the heavy chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0167] In some embodiments, the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain.

[0168] In some embodiments, the light chain of the first structural domain is directly or indirectly connected to the light chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0169] In some embodiments, the N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the light chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0170] In some embodiments, the N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the light chain of the second structural domain, and the N-terminus of the light chain of the second structural domain is directly or indirectly connected to the C-terminus of the third structural domain; or the N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the light chain of the second structural domain, and the N-terminus of the light chain of the second structural domain is directly or indirectly connected to the C-terminus of the third structural domain; or the N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the light chain of the second structural domain, and the C-terminus of the heavy chain of the second structural domain is directly or indirectly connected to the N-terminus of the third structural domain.

[0171] In some embodiments, the C-terminus of the light chain of the first structural domain is directly or indirectly connected to the N-terminus of the light chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

[0172] In some embodiments, the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the N-end of the heavy chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain.

[0173] In some embodiments, the fusion protein further includes a fourth domain capable of binding tumor-associated antigens (TAAs).

[0174] In some implementations, the fourth domain is capable of binding to proteins or tumor antigens that are overexpressed on tumor cells relative to the corresponding non-tumor cells.

[0175] In some embodiments, the fourth domain comprises an antibody or an antigen-binding fragment thereof.

[0176] In some embodiments, the fourth domain antibody is selected from the group consisting of recombinant antibodies, single-domain antibodies, heavy chain antibodies, chimeric antibodies, and bispecific antibodies.

[0177] In some embodiments, the fourth domain antigen-binding fragment is selected from one or more fragments from the group consisting of: Fab, Fab', Fv fragment, F(ab')2, F(ab)2, scFv, di-scFv, VHH, and dAb.

[0178] In some embodiments, the fourth domain can bind to one or more of the following targets: PD-L1, PD-L2, VEGF, VEGFR, FGFR, HER2, HGFR, PIP-LAR, CD44, CD147, TfR, CDCP1, α6β4, α6β3, Trop2, HHLA2, GCC, 5T4, EpCAM, GPRC5D, BCMA, CD19, CD20, HER-2neu, DLL1, DLL3, B 7H3, HER-3, HER-4, EGFR, PSMA, CEA, MUC-1 (mucin), MUC2, MUC3, MUC4, MUC5AC, MUC5B, MUC7, CD123, CD33, CD30, CD38, PTK7, EphA2, NKG2A, Nkp36, Tim3, CD20, Her2, HHLA2, PD-L1, GCC, EGFR, DLL3 and / or B7H3, 5T4 and / or CEA.

[0179] In some embodiments, the fourth domain comprises a single-chain immunoglobulin domain.

[0180] In some embodiments, the fourth domain comprises a single-chain immunoglobulin IgG antibody.

[0181] In some embodiments, the fourth domain single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

[0182] In some embodiments, the fourth domain comprises a single-chain immunoglobulin Fc domain.

[0183] In some embodiments, the fourth domain comprises the Fc domain of a single-chain immunoglobulin IgG antibody.

[0184] In some embodiments, the Fc domain of the single-chain immunoglobulin IgG antibody includes human IgG1 Fc domain, human IgG2 Fc domain, human IgG3 Fc domain, human IgG4 Fc domain, mouse IgG1 Fc domain, mouse IgG2a Fc domain, mouse IgG2b Fc domain, or mouse IgG3 Fc domain.

[0185] In some embodiments, the fourth domain single-chain immunoglobulin Fc fragment comprises CH2 and / or CH3 sequences, wherein the first domain CH2 is located between the variable region and the CH3 domain; preferably, the Fc fragment contains any amino acid sequence selected from the group consisting of: SEQ ID NO: 3, SEQ ID NO: 4.

[0186] In some embodiments, the HCDR1, HCDR2, and / or HCDR3 amino acid sequences or variant sequences thereof in the heavy chain variable region contain any amino acid sequence selected from the group consisting of: SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 64, SEQ ID NO: 65, SEQ ID NO: 66, SEQ ID NO: 69, SEQ ID NO: 70, SEQ ID NO: 71, SEQ ID NO: 74, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 79, SEQ ID NO: 80, SEQ ID NO: 81, SEQ ID NO: 84, SEQ ID NO: 85, SEQ ID NO: 86, SEQ ID NO: 94, SEQ ID NO: 95, SEQ ID NO: 96, SEQ ID NO: 1002, SEQ ID NO: 1003, SEQ ID NO: 1004, SEQ ID NO: 1011, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 64, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 79, SEQ ID NO: 80, SEQ ID NO: 81, SEQ ID NO: 84, SEQ ID NO: 85, SEQ ID NO: 86, SEQ ID NO: 94, SEQ ID NO: 95, SEQ ID NO: 96, SEQ ID NO: 1002, SEQ ID NO: 1003, SEQ ID NO: 1004, SEQ ID NO: 1011, SEQ ID NO: 4 SEQ ID NO: 1012, SEQ ID NO: 1013, SEQ ID NO: 2007, SEQ ID NO: 2008, SEQ ID NO: 2009, SEQ ID NO: 2012, SEQ ID NO: 2013, SEQ ID NO: 2014; the amino acid sequences or variant sequences of the LCDR1, LCDR2 and / or LCDR3 of the light chain variable region, containing any amino acid sequence selected from the following group: SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 89, SEQ ID NO: 90, SEQ ID NO: 91, SEQ ID NO: 1015, SEQ ID NO: 1016, SEQ ID NO: 1017, SEQ ID NO: 2003, SEQ ID NO: 2004, SEQ ID NO: 2005.

[0187] In some embodiments, the fourth structure includes a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain variable region VH comprising any amino acid sequence selected from the group consisting of: SEQ ID NO: 47, SEQ ID NO: 58, SEQ ID NO: 63, SEQ ID NO: 68, SEQ ID NO: 73, SEQ ID NO: 78, SEQ ID NO: 83, SEQ ID NO: 93, SEQ ID NO: 1001, SEQ ID NO: 1010, SEQ ID NO: 2006, SEQ ID NO: 2011.

[0188] In some embodiments, the fourth structure comprises an antibody heavy chain containing an amino acid sequence selected from the group consisting of: SEQ ID NO: 46, SEQ ID NO: 57, SEQ ID NO: 62, SEQ ID NO: 67, SEQ ID NO: 72, SEQ ID NO: 77, SEQ ID NO: 82, SEQ ID NO: 92, SEQ ID NO: 1000, SEQ ID NO: 1005, SEQ ID NO: 1018, SEQ ID NO: 2000, SEQ ID NO: 2010.

[0189] In some embodiments, the fourth structure includes a light chain variable region VL of an antibody light chain, the antibody light chain comprising any amino acid sequence selected from the group consisting of: SEQ ID NO: 53, SEQ ID NO: 88, SEQ ID NO: 1014, SEQ ID NO: 2002.

[0190] In some embodiments, the fourth domain comprises an antibody light chain containing an amino acid sequence selected from the group consisting of SEQ ID NO: 52 and SEQ ID NO: 87.

[0191] In some embodiments, the fourth domain may comprise HCDR1, HCDR2, and HCDR3 of the antibody heavy chain, and LCDR1, LCDR2, and LCDR3 of the antibody light chain, wherein HCDR1, HCDR2, and HCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 59, SEQ ID NO: 60, and SEQ ID NO: 61, respectively, and LCDR1, LCDR2, and LCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 54, SEQ ID NO: 55, and SEQ ID NO: 56, respectively.

[0192] In some embodiments, the fourth structural domain may include a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain VH may include an amino acid sequence as shown in SEQ ID NO: 58, and the fourth structural domain may include a light chain variable region VL of the antibody light chain, the antibody light chain VL may include an amino acid sequence as shown in SEQ ID NO: 53.

[0193] In some embodiments, the fourth structural domain may comprise an antibody heavy chain and / or an antibody light chain, wherein the antibody heavy chain may comprise an amino acid sequence as shown in SEQ ID NO: 57, and the antibody light chain may comprise an amino acid sequence as shown in SEQ ID NO: 52.

[0194] In some embodiments, the fourth domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 48, SEQ ID NO: 49, and SEQ ID NO: 50, respectively.

[0195] In some embodiments, the fourth domain may comprise the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may comprise an amino acid sequence as shown in SEQ ID NO: 47.

[0196] In some embodiments, the fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 46.

[0197] In some embodiments, the fourth domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 64, SEQ ID NO: 65, and SEQ ID NO: 66, respectively.

[0198] In some embodiments, the fourth domain may comprise the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may comprise an amino acid sequence as shown in SEQ ID NO: 63.

[0199] In some embodiments, the fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 62.

[0200] In some embodiments, the fourth domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 69, SEQ ID NO: 70, and SEQ ID NO: 71, respectively.

[0201] In some embodiments, the fourth domain may comprise the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may comprise an amino acid sequence as shown in SEQ ID NO: 68.

[0202] In some embodiments, the fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 67.

[0203] In some embodiments, the fourth domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 74, SEQ ID NO: 75, and SEQ ID NO: 76, respectively.

[0204] In some embodiments, the fourth domain may comprise the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may comprise an amino acid sequence as shown in SEQ ID NO: 73.

[0205] In some embodiments, the fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 72.

[0206] In some embodiments, the fourth domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 79, SEQ ID NO: 80, and SEQ ID NO: 81, respectively.

[0207] In some embodiments, the fourth domain may comprise the heavy chain variable region VHH of a single-domain antibody, the VHH comprising an amino acid sequence as shown in SEQ ID NO: 78.

[0208] In some embodiments, the fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 77.

[0209] In some embodiments, the fourth domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 84, SEQ ID NO: 85, and SEQ ID NO: 86, respectively.

[0210] In some embodiments, the fourth domain may comprise the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may comprise an amino acid sequence as shown in SEQ ID NO: 83.

[0211] In some embodiments, the fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 82.

[0212] In some embodiments, the fourth domain may comprise HCDR1, HCDR2, and HCDR3 of the antibody heavy chain, and LCDR1, LCDR2, and LCDR3 of the antibody light chain, wherein HCDR1, HCDR2, and HCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 94, SEQ ID NO: 95, and SEQ ID NO: 96, respectively, and LCDR1, LCDR2, and LCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 89, SEQ ID NO: 90, and SEQ ID NO: 91, respectively.

[0213] In some embodiments, the fourth structural domain may include a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain VH may include an amino acid sequence as shown in SEQ ID NO: 93, and the fourth structural domain may include a light chain variable region VL of the antibody light chain, the antibody light chain VL may include an amino acid sequence as shown in SEQ ID NO: 88.

[0214] In some embodiments, the fourth structural domain may comprise an antibody heavy chain and / or an antibody light chain, wherein the antibody heavy chain may comprise an amino acid sequence as shown in SEQ ID NO: 92, and the antibody light chain may comprise an amino acid sequence as shown in SEQ ID NO: 87.

[0215] In some embodiments, the fourth domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 1002, SEQ ID NO: 1003, and SEQ ID NO: 1004, respectively.

[0216] In some embodiments, the fourth domain may comprise the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may comprise an amino acid sequence as shown in SEQ ID NO: 1001.

[0217] In some embodiments, the fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 1000 or SEQ ID NO: 1005.

[0218] In some embodiments, the fourth domain may comprise the heavy chains HCDR1, HCDR2, and HCDR3 and the light chains LCDR1, LCDR2, and LCDR3 of the scFv antibody, wherein HCDR1, HCDR2, and HCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 1011, SEQ ID NO: 1012, and SEQ ID NO: 1013, respectively, and LDR1, LCDR2, and LCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 1015, SEQ ID NO: 1016, and SEQ ID NO: 1017, respectively.

[0219] In some embodiments, the fourth domain may comprise the heavy chain variable region VH and the light chain variable region VL of the scFv antibody, wherein the VH may comprise the amino acid sequence shown in SEQ ID NO: 1010 and the VL may comprise the amino acid sequence shown in SEQ ID NO: 1014.

[0220] In some embodiments, the fourth domain may comprise an scFv antibody, which may comprise an amino acid sequence as shown in SEQ ID NO: 1009 or SEQ ID NO: 1018.

[0221] In some embodiments, the fourth domain may comprise the heavy chains HCDR1, HCDR2, and HCDR3 and the light chains LCDR1, LCDR2, and LCDR3 of the scFv antibody, wherein HCDR1, HCDR2, and HCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 2007, SEQ ID NO: 2008, and SEQ ID NO: 2009, respectively, and LDR1, LCDR2, and LCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 2003, SEQ ID NO: 2004, and SEQ ID NO: 2005, respectively.

[0222] In some embodiments, the fourth domain may comprise the heavy chain variable region VH and the light chain variable region VL of the scFv antibody, wherein the VH may comprise the amino acid sequence shown in SEQ ID NO: 2006 and the VL may comprise the amino acid sequence shown in SEQ ID NO: 2002.

[0223] In some embodiments, the fourth domain may comprise an scFv antibody, which may comprise an amino acid sequence as shown in SEQ ID NO: 2001 or SEQ ID NO: 2000.

[0224] In some embodiments, the fourth domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 2012, SEQ ID NO: 2013, and SEQ ID NO: 2014, respectively.

[0225] In some embodiments, the fourth domain may comprise the heavy chain variable region VHH of a single-domain antibody, the VHH comprising an amino acid sequence as shown in SEQ ID NO: 2011.

[0226] In some embodiments, the fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 2010.

[0227] In some implementations, the fourth structural domain does not contain a light chain.

[0228] In some embodiments, the fourth domain fusion peptide described above does not contain a CH1 domain.

[0229] In some implementations, the first domain and the fourth domain are directly or indirectly connected.

[0230] In some implementations, the heavy chain Fc of the first structural domain is directly or indirectly connected to the heavy chain Fc of the fourth structural domain.

[0231] In some embodiments, the heavy chain Fc segment of the first structural domain is connected to the heavy chain Fc of the fourth structural domain via disulfide bonds.

[0232] In some embodiments, the heavy chain of the first structural domain forms a heterodimer with the heavy chain of the fourth structural domain.

[0233] In some embodiments, the heavy chain Fc segments of the first structural domain and the heavy chain Fc segments of the fourth structural domain are connected by a knobs-into-holes structure.

[0234] In some implementations, the knots-into-holes pairing is achieved by including one or more substitutions in the aforementioned heavy chain Fc fragments, which form heterodimeric pairings between heavy chains.

[0235] In some implementations, CH3 in the first structural domain and CH3 in the fourth structural domain are substitution pairs in a pestle-mortar structure.

[0236] In some embodiments, the T366 and / or Y407 amino acid residues on one of the CH3 domains of the first and fourth domains are replaced, and the L368 amino acid residue on the other CH3 domain is replaced.

[0237] In some implementations, the antigen-binding fragment of the first domain is directly or indirectly linked to the fourth domain.

[0238] In some embodiments, the N-terminus of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the fourth domain; or the C-terminus of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the fourth domain.

[0239] In some embodiments, the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the heavy chain of the fourth domain; or the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the heavy chain of the fourth domain; or the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the light chain of the fourth domain; or the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the light chain of the fourth domain.

[0240] In some embodiments, the C-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the fourth domain; or the C-terminus of the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the fourth domain; or the C-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the fourth domain; or the N-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the fourth domain; or the N-terminus of the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the fourth domain; or the N-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the fourth domain; or the N-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the fourth domain; or the N-terminus of the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the fourth domain.

[0241] In some implementations, the first domain is directly or indirectly linked to the antigen-binding fragment of the fourth domain.

[0242] In some embodiments, the N-terminus of the first domain is directly or indirectly connected to the C-terminus of the antigen-binding fragment of the fourth domain; or the C-terminus of the first domain is directly or indirectly connected to the N-terminus of the antigen-binding fragment of the fourth domain.

[0243] In some embodiments, the heavy chain of the first domain is directly or indirectly connected to the heavy chain of the antigen-binding fragment of the fourth domain; or the light chain of the first domain is directly or indirectly connected to the heavy chain of the antigen-binding fragment of the fourth domain; or the heavy chain of the first domain is directly or indirectly connected to the light chain of the antigen-binding fragment of the fourth domain; or the light chain of the first domain is directly or indirectly connected to the light chain of the antigen-binding fragment of the fourth domain.

[0244] In some embodiments, the C-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the first domain; or the C-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the first domain; or the C-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the first domain; or the N-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the first domain; or the N-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the first domain; or the N-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the first domain; or the N-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the first domain; or the N-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the first domain.

[0245] In some implementations, the fourth structural domain and the third structural domain are directly or indirectly connected.

[0246] In some implementations, the fourth structural domain heavy chain is directly or indirectly connected to the third structural domain. For example, the C-terminus of the fourth structural domain heavy chain is directly or indirectly connected to the N-terminus of the third structural domain, or the N-terminus of the fourth structural domain heavy chain is directly or indirectly connected to the C-terminus of the third structural domain.

[0247] In some embodiments, the fourth structural domain light chain is directly or indirectly connected to the third structural domain. For example, the C-terminus of the fourth structural domain light chain is directly or indirectly connected to the N-terminus of the third structural domain, or the N-terminus of the fourth structural domain light chain is directly or indirectly connected to the C-terminus of the third structural domain.

[0248] In some implementations, the second and fourth structural domains are directly or indirectly connected.

[0249] In some embodiments, the heavy chain Fc of the second structural domain is directly or indirectly connected to the heavy chain Fc of the fourth structural domain.

[0250] In some embodiments, the heavy chain Fc segment of the second structural domain is connected to the heavy chain Fc of the fourth structural domain via a disulfide bond.

[0251] In some embodiments, the heavy chain of the second structural domain forms a heterodimer with the heavy chain of the fourth structural domain.

[0252] In some embodiments, the heavy chain Fc segments of the second structural domain and the heavy chain Fc segments of the fourth structural domain are connected by a knobs-into-holes structure.

[0253] In some implementations, knots-into-holes pairing is achieved by including one or more substitutions in the aforementioned heavy chain Fc fragments, which form heterodimeric pairings between heavy chains.

[0254] In some implementations, CH3 in the second structural domain and CH3 in the fourth structural domain are a pestle-mortar substitution pair.

[0255] In some embodiments, the T366 and / or Y407 amino acid residues on one of the CH3 domains of the second and fourth domains are replaced, and the L368 amino acid residue on the other CH3 domain is replaced.

[0256] In some embodiments, the second domain antigen-binding fragment is directly or indirectly linked to the fourth domain.

[0257] In some embodiments, the N-terminus of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the fourth domain; or the C-terminus of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the fourth domain.

[0258] In some embodiments, the heavy chain of the second domain antigen-binding fragment is directly or indirectly linked to the heavy chain of the fourth domain; or the light chain of the second domain antigen-binding fragment is directly or indirectly linked to the heavy chain of the fourth domain; or the heavy chain of the second domain antigen-binding fragment is directly or indirectly linked to the light chain of the fourth domain; or the light chain of the second domain antigen-binding fragment is directly or indirectly linked to the light chain of the fourth domain.

[0259] In some embodiments, the C-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the fourth domain; or the C-terminus of the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the fourth domain; or the C-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the fourth domain; or the N-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the fourth domain; or the N-terminus of the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the fourth domain; or the N-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the fourth domain; or the N-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the fourth domain; or the N-terminus of the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the fourth domain.

[0260] In some embodiments, the second domain is directly or indirectly linked to the antigen-binding fragment of the fourth domain.

[0261] In some embodiments, the N-terminus of the second domain is directly or indirectly connected to the C-terminus of the antigen-binding fragment of the fourth domain; or the C-terminus of the second domain is directly or indirectly connected to the N-terminus of the antigen-binding fragment of the fourth domain.

[0262] In some embodiments, the heavy chain of the second domain is directly or indirectly linked to the heavy chain of the antigen-binding fragment of the fourth domain; or the light chain of the second domain is directly or indirectly linked to the heavy chain of the antigen-binding fragment of the fourth domain; or the heavy chain of the second domain is directly or indirectly linked to the light chain of the antigen-binding fragment of the fourth domain; or the light chain of the second domain is directly or indirectly linked to the light chain of the antigen-binding fragment of the fourth domain.

[0263] In some embodiments, the C-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the second domain; or the C-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the second domain; or the C-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the second domain; or the N-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the second domain; or the N-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the second domain; or the N-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the second domain; or the N-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the second domain; or the N-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the second domain.

[0264] In some implementations, the fourth structural domain may not exist.

[0265] In some embodiments, the fusion protein further includes a fifth domain that conditionally masks the CD3-binding domain in the first domain.

[0266] In some embodiments, the fifth domain includes a masking peptide fragment that can alter the affinity of the first domain for binding to CD3.

[0267] In some embodiments, the fifth domain-masking peptide fragment comprises a polypeptide sequence selected from the following: SEQ ID No:404, SEQ ID No:406, SEQ ID No:407, SEQ ID No:408, SEQ ID No:409, SEQ ID No:410, SEQ ID No:412, SEQ ID No:414, SEQ ID No:415, SEQ ID No:424, SEQ ID No:425, SEQ ID No:426, SEQ ID No:427, SEQ ID No:428, SEQ ID No:403, SEQ ID No:405, SEQ ID No:411, SEQ ID No:413, SEQ ID No:416, SEQ ID No:417, SEQ ID No:418, SEQ ID No:432, SEQ ID No:433, SEQ ID No:434, SEQ ID No:419, SEQ ID No:420, SEQ ID No:421, SEQ ID No:422, SEQ ID No:404, SEQ ID No:405, SEQ ID No:416, SEQ ID No:417, SEQ ID No:418, SEQ ID No:432, SEQ ID No:433, SEQ ID No:434, SEQ ID No:419, SEQ ID No:420, SEQ ID No:421, SEQ ID No:42 ... No:423, SEQ ID No:401, SEQ ID No:402, SEQ ID No:429, SEQ ID No:430, SEQ ID No:431.

[0268] In some embodiments, the fifth domain further includes an enzyme cleavage linker, through which the masking peptide fragment of the fifth domain is linked to the first domain, the second domain, or the fourth domain.

[0269] In some embodiments, the enzyme-ligand contains a protease cleavage site fragment.

[0270] In some embodiments, the enzyme cleavage linker comprises one, two, three, four, five or more protease cleavage site fragments selected from SEQ ID NO:3000-3036.

[0271] In some embodiments, the enzyme-ligand further includes 0, 1, 2, 3, 4, 5, or more linker amino acid sequences selected from the following: GS, GGS, GSGS, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10. The linker amino acid sequence is located between two protease cleavage sites, between a masking peptide fragment and a protease cleavage site fragment, or between a protease cleavage site fragment and a first, second, or fourth domain.

[0272] In some embodiments, the masking peptide fragment of the fifth domain is directly or indirectly linked to the enzyme-linked linker; preferably, the C-terminus of the masking peptide fragment of the fifth domain is directly or indirectly linked to the N-terminus of the enzyme-linked linker, or the N-terminus of the masking peptide fragment of the fifth domain is directly or indirectly linked to the C-terminus of the enzyme-linked linker.

[0273] In some implementations, the first domain and the fifth domain are directly or indirectly connected.

[0274] In some embodiments, the first domain heavy chain is directly or indirectly connected to the fifth domain; preferably, the C-end of the first domain heavy chain is directly or indirectly connected to the N-end of the fifth domain, or the N-end of the first domain heavy chain is directly or indirectly connected to the C-end of the fifth domain.

[0275] In some embodiments, the first structural domain light chain is directly or indirectly connected to the fifth structural domain; preferably, the C-terminus of the first structural domain light chain is directly or indirectly connected to the N-terminus of the fifth structural domain, or the N-terminus of the first structural domain light chain is directly or indirectly connected to the C-terminus of the fifth structural domain.

[0276] In some implementations, the second and fifth structural domains are directly or indirectly connected.

[0277] In some embodiments, the second domain heavy chain is directly or indirectly connected to the fifth domain; preferably, the C-end of the second domain heavy chain is directly or indirectly connected to the N-end of the fifth domain, or the N-end of the second domain heavy chain is directly or indirectly connected to the C-end of the fifth domain.

[0278] In some embodiments, the second structural domain light chain is directly or indirectly connected to the fifth structural domain. Preferably, the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the fifth structural domain, or the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the fifth structural domain.

[0279] In some implementations, the fourth and fifth structural domains are directly or indirectly connected.

[0280] In some embodiments, the fourth structural domain heavy chain is directly or indirectly connected to the fifth structural domain; preferably, the C-end of the fourth structural domain heavy chain is directly or indirectly connected to the N-end of the fifth structural domain, or the N-end of the fourth structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain.

[0281] In some embodiments, the fourth structural domain light chain is directly or indirectly connected to the fifth structural domain; preferably, the C-terminus of the fourth structural domain light chain is directly or indirectly connected to the N-terminus of the fifth structural domain, or the N-terminus of the fourth structural domain light chain is directly or indirectly connected to the C-terminus of the fifth structural domain.

[0282] In some embodiments, the fusion protein further includes a sixth domain: the sixth domain is capable of binding CD28 and / or CTLA4, or the sixth domain may be absent.

[0283] In some implementations, the sixth domain comprises CD86 or CD80 or their functionally active fragments, or variations thereof.

[0284] In some embodiments, the sixth domain is selected from the group consisting of CD86 or CD80 derived from humans or mice, or functionally active fragments thereof or variants thereof.

[0285] In some embodiments, the sixth domain comprises the extracellular domain of CD86 or CD80, or a functionally active fragment thereof, or a variant thereof.

[0286] In some embodiments, the sixth domain comprises the IgV of CD86 or CD80, or a functionally active fragment thereof, or a variant thereof.

[0287] In some embodiments, the sixth domain comprises a CD86 variant polypeptide, wherein the mutant comprises an amino acid substitution mutation of human CD86.

[0288] In some embodiments, the sixth domain comprises a CD86 variant polypeptide comprising an IgV domain amino acid substitution mutant of CD86 and / or an extracellular domain amino acid substitution mutant of human CD86.

[0289] In some embodiments, the sixth domain comprises a CD86 variant polypeptide, the CD86 variant polypeptide comprising an IgV domain amino acid substitution mutant of CD86, the mutation site of the CD86 IgV domain amino acid substitution mutant comprising one, two, three, four, five or more amino acid site mutations selected from the group consisting of: A13I, A13L, A13F, A13M, Q25A, Q25I, Q25V, Q25F, Q25M, F33A, F33L, F33V, F33M, M60R, I89A, I89L, I89V, I89F, I89M, H90I, H90V, H90M, H90F.

[0290] In some embodiments, the sixth domain comprises a CD86 variant polypeptide comprising an IgV domain amino acid substitution mutant of CD86, the amino acid substitution mutant comprising combinations shown below: Q25I / F33L / H90I, Q25V / F33L / H90I, Q25I / F33V / H90I, Q25V / F33V / H90I, Q25I / F33L / H90V, Q25 V / F33L / H90V, Q25I / F33V / H90V, Q25V / F33V / H90V, A13L / Q25I / F33L / H90I, A13I / Q25I / F33L / H 90I, A13L / Q25V / F33L / H90I, A13I / Q25V / F33L / H90I, Q25I / F33L / I89L / H90I, Q25I / F33L / M60R / H90I、Q25V / F33L / I89L / H90I、Q25V / F33L / M60R / H90I、Q25F / F33L / H90I、Q25I / F33L / H90F、Q 25I / F33A / H90I, Q25I / H90I, Q25I, H90I, Q25V / H90V, Q25V / H90I, Q25F / H90I, Q25F / H90V, A13F / Q25I / F33L / H90I, A13M / Q25I / F33L / H90I, Q25A / F33L / H90I, Q25M / F33L / H90I, Q25I / F33M / H90I, Q25I / F33L / I89V / H90I, Q25I / F33L / I89F / H90I, Q25I / F33L / I89M / H90I and Q25I / F33L / H90M.

[0291] In some embodiments, the sixth domain comprises a CD86 variant polypeptide containing the IgV domain amino acid substitution mutant Q25I / F33L / H90I of CD86.

[0292] In some embodiments, the sixth domain comprises a CD86 variant polypeptide, the CD86 variant polypeptide comprising an extracellular domain amino acid substitution mutant of CD86, the extracellular domain amino acid substitution mutant of CD86 comprising one, two, three, four, five or more amino acid site mutations selected from the group consisting of: A13I, A13L, A13F, A13M, Q25A, Q25I, Q25V, Q25F, Q25M, F33A, F33L, F33V, F33M, M60R, I89A, I89L, I89V, I89F, I89M, H90I, H90V, H90M, H90F.

[0293] In some embodiments, the sixth domain comprises an extracellular domain amino acid substitution mutant of CD86, the amino acid substitution mutant comprising combinations shown below: Q25I / F33L / H90I, 25V / F33L / H90I, Q25I / F33V / H90I, Q25V / F33V / H90I, Q25I / F33L / H90V, Q25V / F33L / H90V, Q25I / F33V / H90V, Q25V / F33V / H90V, A13L / Q25I / F33L / H90I, A13I / Q25I / F33L / H90I, A13L / Q25V / F33L / H90I, A13I / Q25V / F33L / H90I, Q25I / F33L / I89L / H90I, Q25I / F33L / M60R / H90I, Q25V / F33L / I89L / H90I, Q25V / F33L / M60R / H90I, Q25F / F33L / H90I, Q25I / F33L / H90F, Q25I / F33A / H90I, Q25I / H90I, Q25I, H90I, Q25V / H90V, Q25V / H90I, Q25F / H90I, Q25F / H90V, A13F / Q25I / F33L / H90I, A13M / Q25I / F33L / H90I, Q25A / F33L / H90I, Q25M / F33L / H90I, Q25I / F33M / H90I, Q25I / F33L / I89V / H90I, Q25I / F33L / I89F / H90I, Q25I / F33L / I89M / H90I and Q25I / F33L / H90M.

[0294] In some embodiments, the sixth domain comprises an extracellular domain amino acid substitution mutant of CD86, the amino acid substitution mutant comprising the combination shown below: Q25I / F33L / H90I.

[0295] In some embodiments, the sixth domain comprises an amino acid sequence selected from SEQ ID NO: 97 to SEQ ID NO: 165.

[0296] In some embodiments, the sixth domain comprises a CD80 variant polypeptide, wherein the mutant comprises an amino acid substitution mutation of human CD80.

[0297] In some embodiments, the sixth domain comprises a CD80 variant polypeptide comprising an IgV domain amino acid substitution mutant of CD80 and / or an extracellular domain amino acid substitution mutant of human CD80.

[0298] In some implementations, the first domain and the sixth domain are directly or indirectly connected.

[0299] In some implementations, the first domain heavy chain is directly or indirectly connected to the sixth domain. For example, the C-terminus of the first domain heavy chain is directly or indirectly connected to the N-terminus of the sixth domain, or the N-terminus of the first domain heavy chain is directly or indirectly connected to the C-terminus of the sixth domain.

[0300] In some implementations, the first structural domain light chain is directly or indirectly connected to the sixth structural domain. For example, the C-terminus of the first structural domain light chain is directly or indirectly connected to the N-terminus of the sixth structural domain, or the N-terminus of the first structural domain light chain is directly or indirectly connected to the C-terminus of the sixth structural domain.

[0301] In some implementations, the second and sixth structural domains are directly or indirectly connected.

[0302] In some implementations, the second domain heavy chain is directly or indirectly connected to the sixth domain. For example, the C-end of the second domain heavy chain is directly or indirectly connected to the N-end of the sixth domain, or the N-end of the second domain heavy chain is directly or indirectly connected to the C-end of the sixth domain.

[0303] In some embodiments, the second structural domain light chain is directly or indirectly connected to the sixth structural domain. For example, the C-terminus of the second structural domain light chain is directly or indirectly connected to the N-terminus of the sixth structural domain, or the N-terminus of the second structural domain light chain is directly or indirectly connected to the C-terminus of the sixth structural domain.

[0304] In some implementations, the fourth and sixth structural domains are directly or indirectly connected.

[0305] In some implementations, the fourth structural domain heavy chain is directly or indirectly connected to the sixth structural domain. For example, the C-end of the fourth structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain, or the N-end of the fourth structural domain heavy chain is directly or indirectly connected to the C-end of the sixth structural domain.

[0306] In some embodiments, the fourth structural domain light chain is directly or indirectly connected to the sixth structural domain. For example, the C-terminus of the fourth structural domain light chain is directly or indirectly connected to the N-terminus of the sixth structural domain, or the N-terminus of the fourth structural domain light chain is directly or indirectly connected to the C-terminus of the sixth structural domain.

[0307] In some implementations, the third and sixth structural domains are directly or indirectly connected.

[0308] In some embodiments, the fusion protein includes a first domain, a second domain, a third domain, and a sixth domain, wherein: the first domain is directly or indirectly connected to the second domain, the first domain is directly or indirectly connected to the third domain, and the second domain is directly or indirectly connected to the sixth domain.

[0309] Preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain.

[0310] More preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the third structural domain, and the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the third structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain. Alternatively, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the sixth structural domain.

[0311] Preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain; and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the second structural domain light chain is directly or indirectly connected to the sixth structural domain.

[0312] More preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the third structural domain, and the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the third structural domain, and the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the sixth structural domain. Alternatively, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the sixth structural domain.

[0313] Preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain; and the first structural domain light chain is directly or indirectly connected to the third structural domain, and the second structural domain light chain is directly or indirectly connected to the sixth structural domain.

[0314] More preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the third structural domain, and the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the third structural domain, and the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the sixth structural domain. Alternatively, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the sixth structural domain.

[0315] Preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain; and the first structural domain light chain is directly or indirectly connected to the third structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain.

[0316] More preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the third structural domain, and the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the third structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain. Alternatively, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the sixth structural domain.

[0317] In some embodiments, the second structural domain is directly or indirectly connected to the fourth structural domain, the first structural domain is directly or indirectly connected to the fourth structural domain, the fourth structural domain is directly or indirectly connected to the third structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

[0318] Preferably, the second structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fourth structural domain; and the fourth structural domain heavy chain is directly or indirectly connected to the third structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain.

[0319] More preferably, the second structural domain is directly or indirectly connected to the fourth structural domain; and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the fourth structural domain; and the C-end of the heavy chain of the fourth structural domain is directly or indirectly connected to the N-end of the third structural domain; and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the sixth structural domain.

[0320] In some implementations, the first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain is directly or indirectly connected to the third structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

[0321] Preferably, the first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain.

[0322] More preferably, the first structural domain is directly or indirectly connected to the second structural domain, and the N end of the heavy chain of the first structural domain is directly or indirectly connected to the C end of the fourth structural domain, and the C end of the heavy chain of the first structural domain is directly or indirectly connected to the N end of the third structural domain, and the C end of the heavy chain of the second structural domain is directly or indirectly connected to the N end of the sixth structural domain.

[0323] Preferably, the first structural domain is directly or indirectly connected to the second structural domain, the light chain of the first structural domain is directly or indirectly connected to the fourth structural domain, the heavy chain of the first structural domain is directly or indirectly connected to the third structural domain, and the heavy chain of the second structural domain is directly or indirectly connected to the sixth structural domain.

[0324] More preferably, the first structural domain is directly or indirectly connected to the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the fourth structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the third structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the sixth structural domain; or, the first structural domain is directly or indirectly connected to the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the fourth structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the third structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the sixth structural domain.

[0325] In some implementations, the first structural domain is directly or indirectly connected to the second structural domain; and the first structural domain is directly or indirectly connected to the third structural domain; and the second structural domain is directly or indirectly connected to the fourth structural domain; and the second structural domain is directly or indirectly connected to the sixth structural domain.

[0326] Preferably, the first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain.

[0327] More preferably, the first structural domain is directly or indirectly connected to the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the heavy chain of the second structural domain is directly or indirectly connected to the C-end of the fourth structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the sixth structural domain.

[0328] Preferably, the first structural domain is directly or indirectly connected to the second structural domain, the heavy chain of the first structural domain is directly or indirectly connected to the third structural domain, the light chain of the second structural domain is directly or indirectly connected to the fourth structural domain, and the heavy chain of the second structural domain is directly or indirectly connected to the sixth structural domain.

[0329] More preferably, the first structural domain is directly or indirectly connected to the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the fourth structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the sixth structural domain; or, the first structural domain is directly or indirectly connected to the second structural domain; and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the fourth structural domain; and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the sixth structural domain.

[0330] In some implementations, the first structural domain is directly or indirectly connected to the second structural domain; and the first structural domain or the second structural domain is directly or indirectly connected to the fifth structural domain.

[0331] Preferably, the first domain heavy chain is directly or indirectly connected to the second domain heavy chain, and the first domain heavy chain or the second domain heavy chain is directly or indirectly connected to the fifth domain.

[0332] More preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N end of the first structural domain heavy chain or the N end of the second structural domain heavy chain is directly or indirectly connected to the C end of the fifth structural domain.

[0333] Preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain light chain or the second structural domain light chain is directly or indirectly connected to the fifth structural domain.

[0334] More preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N end of the first structural domain light chain or the N end of the second structural domain light chain is directly or indirectly connected to the C end of the fifth structural domain.

[0335] In some embodiments, the second structural domain is directly or indirectly connected to the fourth structural domain; and the first structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain is directly or indirectly connected to the fifth structural domain.

[0336] In some preferred embodiments, the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain; preferably, the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the fourth structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain.

[0337] In some preferred embodiments, the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain; preferably, the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the fourth structural domain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the fifth structural domain.

[0338] In some implementations, the first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain is directly or indirectly connected to the fifth structural domain.

[0339] In some preferred embodiments, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain light chain is directly or indirectly connected to the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the fourth structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain; or preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the fourth structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain.

[0340] In some preferred embodiments, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain light chain is directly or indirectly connected to the fourth structural domain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the fourth structural domain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the fifth structural domain.

[0341] In some implementations, the first structural domain is directly or indirectly connected to the second structural domain; and the first structural domain is directly or indirectly connected to the fifth structural domain, and the second structural domain is directly or indirectly connected to the fourth structural domain.

[0342] In some preferred embodiments, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end domain of the fifth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the fourth structural domain.

[0343] In some preferred embodiments, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end domain of the fifth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the fourth structural domain.

[0344] In some preferred embodiments, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, and the second structural domain light chain is directly or indirectly connected to the fourth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end domain of the fifth structural domain, and the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the fourth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end domain of the fifth structural domain, and the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the fourth structural domain.

[0345] In some preferred embodiments, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain, and the second structural light chain is directly or indirectly connected to the fourth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end domain of the fifth structure, and the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the fourth structural domain; or preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end domain of the fifth structure, and the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the fourth structural domain.

[0346] In some implementations, the first structural domain is directly or indirectly connected to the second structural domain; and the first structural domain is directly or indirectly connected to the third structural domain, and the first structural domain is directly or indirectly connected to the fifth structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

[0347] In some preferred embodiments, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

[0348] In some preferred embodiments, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the fifth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

[0349] In some implementations, the first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain, and the first structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain is directly or indirectly connected to the fifth structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

[0350] In some preferred embodiments, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the first structural domain light chain is directly or indirectly connected to the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the fourth structural domain, the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

[0351] In some preferred embodiments, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the first structural domain light chain is directly or indirectly connected to the fourth structural domain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the fourth structural domain, the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the fifth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

[0352] In some embodiments, the second structural domain is directly or indirectly connected to the fourth structural domain; and the first structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain is directly or indirectly connected to the fifth structural domain, and the second structural domain is directly or indirectly connected to the third structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

[0353] In some preferred embodiments, the second structural domain is directly or indirectly connected to the fourth structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, the second structural domain heavy chain is directly or indirectly connected to the third structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the second structural domain is directly or indirectly connected to the fourth structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the fourth structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

[0354] In some preferred embodiments, the second structural domain is directly or indirectly connected to the heavy chain of the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain, the second structural domain heavy chain is directly or indirectly connected to the third structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the second structural domain is directly or indirectly connected to the heavy chain of the fourth structural domain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the fourth structural domain, and the N-end of the first structural domain light chain is directly or indirectly connected to the fifth structural domain, the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

[0355] In some implementations, the first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain, and the first structural domain is directly or indirectly connected to the fifth structural domain, and the second structural domain is directly or indirectly connected to the fourth structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

[0356] In some preferred embodiments, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain, and the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the fourth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

[0357] In some preferred embodiments, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, and the second structural domain light chain is directly or indirectly connected to the fourth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain. The first structural domain is directly or indirectly connected to the second structural domain, and the N end of the light chain of the second structural domain is directly or indirectly connected to the C end of the fourth structural domain, and the C end of the heavy chain of the second structural domain is directly or indirectly connected to the N end of the sixth structural domain; or preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C end of the first structural domain heavy chain is directly or indirectly connected to the N end of the third structural domain, and the N end of the first structural domain heavy chain is directly or indirectly connected to the C end of the fifth structural domain, and the C end of the second structural domain light chain is directly or indirectly connected to the N end of the fourth structural domain, and the C end of the second structural domain heavy chain is directly or indirectly connected to the N end of the sixth structural domain.

[0358] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a first domain heavy chain from its N-terminus to its C-terminus; the third polypeptide includes a second domain heavy chain from its N-terminus to its C-terminus; and the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fourth polypeptide may or may not be present.

[0359] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a second domain heavy chain from its N-terminus to its C-terminus; and the fourth polypeptide includes a domain heavy chain from its N-terminus to its C-terminus.

[0360] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a domain heavy chain from its N-terminus to its C-terminus; the third polypeptide includes a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; and the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fourth polypeptide may or may not be present.

[0361] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; and the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fourth polypeptide may or may not be present.

[0362] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes, from its N-terminus to its C-terminus, a first domain heavy chain CD3 antigen-binding fragment, a linker, a fourth domain heavy chain, a linker, and a third domain in sequence; the third polypeptide includes, from its N-terminus to its C-terminus, a second domain heavy chain, a linker, and a sixth domain in sequence; the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus. The first, fourth, and fifth polypeptides may or may not be present.

[0363] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from its N-terminus to its C-terminus, a first domain light chain, a linker, and a fourth domain heavy chain; the second polypeptide comprises, from its N-terminus to its C-terminus, a first domain heavy chain, a linker, and a third domain; the third polypeptide comprises, from its N-terminus to its C-terminus, a second domain heavy chain, a linker, and a sixth domain; the fourth polypeptide comprises, from its N-terminus to its C-terminus, a second domain light chain; and the fifth polypeptide comprises, from its N-terminus to its C-terminus, a fourth domain light chain; wherein the fourth polypeptide and the fifth polypeptide may or may not be present.

[0364] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fourth domain heavy chain TAA antigen-binding fragment, a linker, a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide, the fourth polypeptide, and the fifth polypeptide may or may not be present.

[0365] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from its N-terminus to its C-terminus, a fourth domain TAA antigen-binding fragment, a linker, and a light chain of a first domain; the second polypeptide comprises, from its N-terminus to its C-terminus, a first domain heavy chain, a linker, and a third domain; the third polypeptide comprises, from its N-terminus to its C-terminus, a second domain heavy chain, a linker, and a sixth domain; the fourth polypeptide comprises, from its N-terminus to its C-terminus, a second domain light chain; and the fifth polypeptide comprises, from its N-terminus to its C-terminus, a fourth domain light chain; wherein the fourth polypeptide and the fifth polypeptide may or may not be present.

[0366] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a fourth domain TAA antigen-binding fragment, a linker, a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide, the fourth polypeptide, and the fifth polypeptide may or may not be present.

[0367] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a second domain light chain, a linker, and a fourth domain TAA antigen-binding fragment from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fifth polypeptide may or may not be present.

[0368] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a fourth domain TAA antigen-binding fragment, a linker, and a second domain light chain linker from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fifth polypeptide may or may not be present.

[0369] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fifth domain, a linker, and a first domain heavy chain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a second domain heavy chain from its N-terminus to its C-terminus; and the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fourth polypeptide may or may not be present.

[0370] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein the first polypeptide includes a fifth domain, a linker, and a light chain of the first domain sequentially from the N-terminus to the C-terminus, wherein the linker may be absent; the second polypeptide includes a heavy chain of the first domain from the N-terminus to the C-terminus; the third polypeptide includes a heavy chain of the second domain from the N-terminus to the C-terminus; and the fourth polypeptide includes a light chain of the second domain from the N-terminus to the C-terminus; wherein the fourth polypeptide may or may not be present.

[0371] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fifth domain, a linker, a first domain heavy chain CD3 antigen-binding fragment, a linker, and a fourth domain heavy chain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a second domain heavy chain from its N-terminus to its C-terminus; the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide, the fourth polypeptide, and the fifth polypeptide may or may not be present.

[0372] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from N-terminus to C-terminus, a fifth domain, a linker, and a light chain of the first domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a first domain heavy chain, a CD3 antigen-binding fragment, a linker, and a fourth domain heavy chain; the third polypeptide comprises, from N-terminus to C-terminus, a second domain heavy chain; the fourth polypeptide comprises, from N-terminus to C-terminus, a second domain light chain; and the fifth polypeptide comprises, from N-terminus to C-terminus, a fourth domain light chain; wherein the fourth and fifth polypeptides may or may not be present.

[0373] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from N-terminus to C-terminus, a first domain light chain, a linker, and a fourth domain heavy chain; the second polypeptide comprises, from N-terminus to C-terminus, a fifth domain, a linker, and a first domain heavy chain, wherein the linker may be absent; the third polypeptide comprises, from N-terminus to C-terminus, a second domain heavy chain; the fourth polypeptide comprises, from N-terminus to C-terminus, a second domain light chain; and the fifth polypeptide comprises, from N-terminus to C-terminus, a fourth domain light chain; wherein the fourth and fifth polypeptides may or may not be present.

[0374] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from N-terminus to C-terminus, a fifth domain, a linker, a light chain of the first domain, a linker, and a heavy chain of the fourth domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first domain, wherein the linker may be absent; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain of the second domain; and the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth domain; wherein the fourth polypeptide and the fifth polypeptide may be present or absent.

[0375] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fifth domain, a linker, and a first domain heavy chain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a fourth domain TAA antigen-binding fragment, a linker, and a second domain heavy chain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide, the fourth polypeptide, and the fifth polypeptide may or may not be present.

[0376] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a fifth domain, a linker, and a light chain of the first domain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the second polypeptide includes a heavy chain of the first domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a fourth domain TAA antigen-binding fragment, a linker, and a heavy chain of the second domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a light chain of the second domain sequentially from its N-terminus to its C-terminus; and the fifth polypeptide includes a light chain of the fourth domain sequentially from its N-terminus to its C-terminus; wherein the fourth polypeptide and the fifth polypeptide may be present or absent.

[0377] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fifth domain, a linker, and a first domain heavy chain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a second domain heavy chain from its N-terminus to its C-terminus; the fourth polypeptide includes a fourth domain TAA antigen-binding fragment, a linker, and a second domain light chain linker sequentially from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fifth polypeptide may or may not be present.

[0378] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from N-terminus to C-terminus, a fifth domain, a linker, and a light chain of the first domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first domain; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a fourth domain TAA antigen-binding fragment, a linker, and a light chain linker of the second domain; the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth domain; wherein the fifth polypeptide may or may not be present.

[0379] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fifth domain, a linker, and a first domain heavy chain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a second domain heavy chain from its N-terminus to its C-terminus; the fourth polypeptide includes a second domain light chain, a linker, and a fourth domain TAA antigen-binding fragment sequentially from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fifth polypeptide may or may not be present.

[0380] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from N-terminus to C-terminus, a fifth domain, a linker, and a light chain of the first domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first domain; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain of the second domain, a linker, and a TAA antigen-binding fragment of the fourth domain; the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth domain; wherein the fifth polypeptide may or may not be present.

[0381] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fifth domain, a linker, a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; and the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fourth polypeptide may or may not be present.

[0382] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein the first polypeptide includes, from N-terminus to C-terminus, a fifth domain, a linker, and a light chain of the first domain, wherein the linker may be absent; the second polypeptide includes, from N-terminus to C-terminus, a heavy chain of the first domain, a linker, and a third domain; the third polypeptide includes, from N-terminus to C-terminus, a heavy chain of the second domain, a linker, and a sixth domain; the fourth polypeptide includes, from N-terminus to C-terminus, a light chain of the second domain; wherein the fourth polypeptide may or may not be present.

[0383] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes, from its N-terminus to its C-terminus, a fifth domain, a linker, a first domain heavy chain CD3 antigen-binding fragment, a linker, a fourth domain heavy chain, a linker, and a third domain in sequence, wherein the linker may be absent; the third polypeptide includes, from its N-terminus to its C-terminus, a second domain heavy chain, a linker, and a sixth domain in sequence; the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide, the fourth polypeptide, and the fifth polypeptide may or may not be present.

[0384] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from N-terminus to C-terminus, a fifth domain, a linker, and a light chain of the first domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a first domain heavy chain CD3 antigen-binding fragment, a linker, a fourth domain heavy chain, a linker, and a third domain; the third polypeptide comprises, from N-terminus to C-terminus, a second domain heavy chain, a linker, and a sixth domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a second domain light chain; and the fifth polypeptide comprises, from N-terminus to C-terminus, a fourth domain light chain; wherein the fourth and fifth polypeptides may be present or absent.

[0385] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from N-terminus to C-terminus, a first domain light chain, a linker, and a fourth domain heavy chain; the second polypeptide comprises, from N-terminus to C-terminus, a fifth domain, a linker, a first domain heavy chain, a linker, and a third domain, wherein the linker may be absent; the third polypeptide comprises, from N-terminus to C-terminus, a second domain heavy chain, a linker, and a sixth domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a second domain light chain; and the fifth polypeptide comprises, from N-terminus to C-terminus, a fourth domain light chain; wherein the fourth and fifth polypeptides may or may not be present.

[0386] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide, from its N-terminus to its C-terminus, sequentially includes a fifth domain, a linker, a light chain of the first domain, a linker, and a heavy chain of the fourth domain, wherein the linker may be absent; the second polypeptide, from its N-terminus to its C-terminus, sequentially includes a heavy chain of the first domain, a linker, and a third domain; the third polypeptide, from its N-terminus to its C-terminus, sequentially includes a heavy chain of the second domain, a linker, and a sixth domain; the fourth polypeptide, from its N-terminus to its C-terminus, includes a light chain of the second domain; the fifth polypeptide, from its N-terminus to its C-terminus, includes a light chain of the fourth domain; wherein the fourth polypeptide and the fifth polypeptide may be present or absent.

[0387] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fifth domain, a linker, a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a fourth domain TAA antigen-binding fragment, a linker, a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide, the fourth polypeptide, and the fifth polypeptide may or may not be present.

[0388] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from its N-terminus to its C-terminus, a fifth domain, a linker, and a light chain of the first domain, wherein the linker may be absent; the second polypeptide comprises, from its N-terminus to its C-terminus, a heavy chain of the first domain, a linker, and a third domain, wherein the linker may be absent; the third polypeptide comprises, from its N-terminus to its C-terminus, a fourth domain (TAA antigen-binding fragment), a linker, a heavy chain of the second domain, a linker, and a sixth domain; the fourth polypeptide comprises, from its N-terminus to its C-terminus, a light chain of the second domain; and the fifth polypeptide comprises, from its N-terminus to its C-terminus, a light chain of the fourth domain; wherein the fourth and fifth polypeptides may be present or absent.

[0389] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fifth domain, a linker, a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus, wherein the linker may or may not be present; the third polypeptide includes a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a second domain light chain, a linker, and a fourth domain TAA antigen-binding fragment from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fifth polypeptide may or may not be present.

[0390] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from N-terminus to C-terminus, a fifth domain, a linker, and a light chain of the first domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first domain, a linker, and a third domain; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second domain, a linker, and a sixth domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain of the second domain, a linker, and a TAA antigen-binding fragment of the fourth domain; the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth domain; wherein the fifth polypeptide may or may not be present.

[0391] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fifth domain, a linker, a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a fourth domain TAA antigen-binding fragment, a linker, and a second domain light chain linker from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fifth polypeptide may or may not be present.

[0392] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from N-terminus to C-terminus, a fifth domain, a linker, and a light chain of the first domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first domain, a linker, and a third domain, wherein the linker may be absent; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second domain, a linker, and a sixth domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a fourth domain TAA antigen-binding fragment, a linker, and a light chain linker of the second domain; the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth domain; wherein the fifth polypeptide may or may not be present.

[0393] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein the first polypeptide comprises, from N-terminus to C-terminus, a first domain light chain, a linker, and a fourth domain heavy chain; the second polypeptide comprises, from N-terminus to C-terminus, a fifth domain, a linker, a first domain heavy chain, a linker, and a third domain, wherein the linker may be absent; the third polypeptide comprises, from N-terminus to C-terminus, a second domain heavy chain, a linker, and a sixth domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a second domain light chain; and the fifth polypeptide comprises, from N-terminus to C-terminus, a fourth domain light chain; wherein the fourth and fifth polypeptides may or may not be present.

[0394] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 46, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0395] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 167, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 177, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0396] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 77, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0397] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 167, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 190, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0398] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3227, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 46, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0399] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3232, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 177, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0400] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3230, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 46, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0401] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3231, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 46, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0402] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 62, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0403] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3225, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3222, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0404] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3226, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3223, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0405] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3225, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3216, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0406] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3226, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3217, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0407] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3227, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 77, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0408] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3228, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 77, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0409] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3229, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 77, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0410] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3230, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 77, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0411] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3231, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 77, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0412] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3233, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3216, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0413] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3234, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3217, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0414] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3235, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 177, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0415] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3236, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 177, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0416] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3237, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 177, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0417] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3238, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 177, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0418] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3232, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 190, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0419] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3232, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 184, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0420] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1007, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1005, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0421] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1020, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1008, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1006, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0422] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1005, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0423] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3232, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1006, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0424] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1018, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0425] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3232, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1019, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0426] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2000, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0427] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 167, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2015, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0428] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 342, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2016, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0429] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 168, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2017, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0430] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2021, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2000, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0431] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2024, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2000, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0432] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2027, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2000, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0433] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2022, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2000, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0434] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2023, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2000, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0435] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2030, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2015, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0436] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2010, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0437] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 167, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2018, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0438] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2030, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2018, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0439] In some embodiments, the fusion protein comprises a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 46, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

[0440] In some embodiments, the fusion protein includes a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein the first polypeptide includes the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide includes the amino acid sequence selected from SEQ ID NO: 440, SEQ ID NO: 443-476, and the third polypeptide includes the amino acid sequence shown in SEQ ID NO: 46.

[0441] In some implementations, the indirect connection includes a connection via a connector sub-connection.

[0442] Preferably, the linker comprises an amino acid sequence selected from the group consisting of: SS, GS, GGS, GSGS, SEQ ID NO: 5 to SEQ ID NO: 10.

[0443] The present invention also provides an immunoconjugate comprising the fusion polypeptide as described above.

[0444] The present invention also provides a nucleic acid molecule that encodes the fusion polypeptide as described above.

[0445] The present invention also provides a carrier comprising the nucleic acid molecules described above.

[0446] The present invention also provides a cell comprising and / or expressing the fusion polypeptide, immune conjugate, nucleic acid molecule, and / or carrier as described above.

[0447] The present invention also provides a composition comprising the fusion peptide, immunoconjugate, nucleic acid molecule, and / or carrier, and / or cell, as described above, and optionally a pharmaceutically acceptable carrier.

[0448] The present invention also provides a method for preparing the fusion polypeptide as described above, comprising culturing cells as described above under conditions that enable the fusion polypeptide to be expressed.

[0449] The present invention also provides a method for inhibiting the growth and / or proliferation of tumors or tumor cells, comprising administering an effective amount of the fusion polypeptide, immune conjugate, nucleic acid molecule, and / or carrier, cell, and / or composition as described above.

[0450] The present invention also provides the use of the fusion peptides, immunoconjugates, nucleic acid molecules, and / or carriers, cells, and / or compositions described above in the preparation of medicaments, wherein the medicaments are used for the prevention, improvement, and / or treatment of tumors.

[0451] In some embodiments, the tumor includes solid tumors and / or hematomas; the tumors include, but are not limited to, colon tumors, breast tumors, lung tumors, gastric tumors, melanoma, head and neck tumors, lymphoma, nasopharyngeal tumors, cervical tumors, esophageal tumors, kidney tumors, squamous cell carcinoma of the skin, endometrial tumors, liver tumors, bladder tumors, urothelial tumors, and skin tumors.

[0452] Other aspects and advantages of this application will readily be apparent to those skilled in the art from the detailed description below. Only exemplary embodiments of this application are shown and described in the following detailed description. As will be appreciated by those skilled in the art, the content of this application enables them to make modifications to the disclosed specific embodiments without departing from the spirit and scope of the invention to which this application pertains. Accordingly, the descriptions in the accompanying drawings and specification of this application are merely exemplary and not restrictive. Attached Figure Description

[0453] The specific features of the invention involved in this application are shown in the appended claims. The features and advantages of the invention can be better understood by referring to the exemplary embodiments and drawings described in detail below. A brief description of the drawings is as follows:

[0454] Figure 1A shows an exemplary structural diagram of the multifunctional fusion peptide of this application containing CD3, TAA and CD86 / CD80 variants.

[0455] Figure 1B shows an exemplary structural diagram of the multifunctional fusion peptide of this application containing a first domain, a second domain, a third domain, a fourth domain, and a fifth domain.

[0456] Figure 1C shows an exemplary structural diagram of the multifunctional fusion peptide of this application, which may contain a first structural domain, a second structural domain, a third structural domain, and a fourth structural domain. In this application, the fourth or sixth structural domain involved in the antibody may not be present.

[0457] Figure 1D shows an exemplary structural diagram of the multifunctional fusion peptide of this application, which may contain a first domain, a second domain, a fourth domain, and a fifth domain. In this application, the fourth domain, which is involved in the antibody-dependent synthesis, may not be present.

[0458] Figure 1E shows an exemplary format of the multifunctional fusion peptide of this application containing a first domain, a second domain, a third domain, a fourth domain, and a fifth domain.

[0459] Figure 2A shows the structures of CD3xHer2 fusion peptide complexes TCB 160, TCB 161, PAT-003, and PAT-004 containing different CD86 mutants, and their corresponding CD3xHer2 bispecific antibodies TCB 160 without CD86.

[0460] Figure 2B shows the killing effect of CD3xHer2 fusion peptide complexes TCB 160, TCB 161, PAT-003, PAT-004 containing different CD86 mutants and CD3xHer2 fusion peptide complex TCB 160 without CD86 on HCC824 of SHP77.

[0461] Figure 3A shows the antibody structures of CD3x5T4 fusion polypeptide complexes TCB 340, PAT-026, and PAT-027 containing different CD86 mutants, and their corresponding CD3x5T4 bispecific antibody TCB 340 without CD86.

[0462] Figure 3B shows the binding ability of CD3x5T4 fusion peptide complexes TCB 340, PAT-026, and PAT-027 containing different CD86 mutants, and their corresponding CD3x5T4 bispecific antibody TCB 340 without CD86, to tumor target cells H1975.

[0463] Figure 3C shows the killing effect of CD3x5T4 fusion peptide complexes TCB 340, PAT-026, and PAT-027 containing different CD86 mutants, and their corresponding CD3x5T4 bispecific antibody TCB 340 without CD86 on H226.

[0464] Figure 4A shows the antibody structures of CD3xEGFR fusion peptide complexes AN_PB_Ab_111, AN_PB_Ab_123, and AN_PB_Ab_124 containing different CD86 mutants, and their corresponding CD3xEGFR bispecific antibody AN_PB_Ab_110 which does not contain CD86.

[0465] Figure 4B shows the SDS-PAGE electrophoresis results of CD3xEGFR fusion peptide complexes AN_PB_Ab_111, AN_PB_Ab_123, and AN_PB_Ab_124 containing different CD86 mutants and their corresponding CD3xEGFR bispecific antibody AN_PB_Ab_110 without CD86.

[0466] Figure 4C shows the killing effect of CD3xEGFR fusion peptide complexes AN_PB_Ab-111, AN_PB_Ab-123, and AN_PB_Ab-124 containing different CD86 mutants and CD3xEGFR fusion peptide complex AN_PB_Ab-110 without CD86 on SHP77.

[0467] Figure 5A shows the antibody construction format used in the screening of CD3-masked peptides and the construction format of the CD3-unmasked control antibody (AN_TCB_160).

[0468] Figure 5B shows the binding ability of different masking peptide antibodies to Jurkat cells.

[0469] Figure 5C shows the results of different masking peptide antibodies regulating the killing of NUGC-4 tumor cells by primary PBMC cells before and after MTSP1 enzyme digestion.

[0470] Figure 6A shows the structures of CD3x5T4 fusion polypeptide complexes TCB 340, PAT-026, and PAT-027 containing different masking peptides and the same enzyme digestion fragments, and their corresponding CD3x5T4 bispecific antibody TCB 339 without masking function.

[0471] Figure 6B shows the binding ability of CD3x5T4 fusion polypeptide complexes TCB 340, PAT-026, and PAT-027, containing different masking peptides and the same digested fragments, and their corresponding CD3x5T4 bispecific antibody TCB 339 without masking function to tumor target cells H1975 before and after MTSP-1 digestion.

[0472] Figure 6C shows the killing effect of CD3x5T4 fusion polypeptide complexes TCB 340, PAT-026, and PAT-027, which contain different masking peptides and the same digestion fragments, before and after MTSP-1 digestion, and their corresponding CD3x5T4 bispecific antibody TCB 339 without masking function on H226.

[0473] Figure 7A shows the structural diagrams of the CD3xEGFR bispecific antibodies AN_PB_Ab-118, AN_PB_Ab-119, and AN_PB_Ab-120 with CD3 binding domain masking function and the CD3xEGFR bispecific antibody AN_PB_Ab-110 without CD3 binding domain masking function of this application.

[0474] Figure 7B shows the SDS-PAGE electrophoresis results of the CD3xEGFR bispecific antibodies AN_PB_Ab-118, AN_PB_Ab-119, and AN_PB_Ab-120 with CD3 binding domain masking function and the CD3xEGFR bispecific antibody AN_PB_Ab-110 without CD3 binding domain masking function of this application.

[0475] Figure 7C shows the results of detecting the binding ability of AN_PB_Ab-110, AN_PB_Ab-118, AN_PB_Ab-119, and AN_PB_Ab-120 to human PBMCs before and after enzyme digestion.

[0476] Figure 7D shows the regulation of primary PBMC cells killing H358 tumor target cells by CD3xEGFR bispecific antibodies AN_PB_Ab-118, AN_PB_Ab-119, and AN_PB_Ab-120 with CD3 binding domain masking function before and after enzyme digestion, and by CD3xEGFR bispecific antibody AN_PB_Ab-110 without CD3 binding domain masking function.

[0477] Figure 8A shows the killing effect of CD3xHer2 fusion peptide complexes AN_TCB_325, AN_CLA_003, AN_CLA_004, AN_CLA_005, and AN_CLA_006, which contain the same masking peptide but different digestion fragments, before and after MTSP-1 digestion, and their corresponding CD3xHer2 bispecific antibody TCB 160 without masking function on N87.

[0478] Figure 9A shows the structures of CD3x5T4 fusion polypeptide complexes A PAT-021, PAT-024, and PAT-025 containing the same masking peptide but different enzyme fragments, and their corresponding CD3x5T4 bispecific antibody TCB 339 without masking function.

[0479] Figure 9B shows the binding ability of CD3x5T4 fusion polypeptide complexes A PAT-021, PAT-024, and PAT-025, containing the same masking peptide but different digestion fragments, and their corresponding CD3x5T4 bispecific antibody TCB 339 without masking function to tumor target cells H1975 before and after MTSP-1 digestion.

[0480] Figure 9C shows the killing effect of CD3x5T4 fusion polypeptide complexes A PAT-021, PAT-024, and PAT-025, containing the same masking peptide but different digestion fragments, and their corresponding CD3x5T4 bispecific antibody TCB 339 without masking function on H226 before and after MTSP-1 digestion.

[0481] Figure 10A shows the antibody structures of the CD3xEGFR bispecific antibodies AN_PB_Ab-118, AN_PB_Ab-121, and AN_PB_Ab-122 with CD3 binding domain masking function and the CD3xEGFR bispecific antibody AN_PB_Ab-110 without CD3 binding domain masking function of this application.

[0482] Figure 10B shows the SDS-PAGE electrophoresis results of the CD3xEGFR bispecific antibodies AN_PB_Ab-118, AN_PB_Ab-121, and AN_PB_Ab-122 with CD3 binding domain masking function and the CD3xEGFR bispecific antibody AN_PB_Ab-110 without CD3 binding domain masking function of this application.

[0483] Figure 10C shows the results of detecting the binding ability of AN_PB_Ab-118, AN_PB_Ab-121, AN_PB_Ab-122 before and after enzyme digestion, and AN_PB_Ab-110 for human PBMCs.

[0484] Figure 10D shows the regulation of primary PBMC cells killing H358 tumor target cells by CD3xEGFR bispecific antibody AN_PB_Ab-118 with CD3 binding domain masking function before and after enzyme digestion, and by CD3xEGFR bispecific antibody AN_PB_Ab-110 without CD3 binding domain masking function.

[0485] Figure 11A shows the antibody structures of CD3xHer2 fusion polypeptide complexes TCB 327, PAT-012, and AT-013 containing the same masking peptide, the same enzyme digestion fragment, and different CD86 mutants, and their corresponding CD3xHer2 bispecific antibody TCB 160.

[0486] Figure 11B shows the N87 binding ability of CD3xHer2 fusion polypeptide complexes TCB 327, PAT-012, AT-013, and their corresponding CD3xHer bispecific antibody TCB 160 to tumor target cells before and after MTSP-1 digestion, which contain the same masking peptide, the same digestion fragment, and different CD86 mutants.

[0487] Figure 11C shows the killing effect of CD3xHer2 fusion polypeptide complexes TCB 327, PAT-012, AT-013, and their corresponding CD3xHer2 bispecific antibody TCB 160 on N87 before and after MTSP-1 digestion, which contain the same masking peptide, the same digestion fragment, and different CD86 mutants.

[0488] Figure 12A shows the antibody structures of CD3xHer2 fusion polypeptide complexes TCB 327, PAT-014, and PAT-015 containing different masking peptides, the same enzyme digestion fragments, and the same CD86 mutant, and their corresponding CD3xHer2 bispecific antibody TCB 160.

[0489] Figure 12B shows the binding ability of CD3xHer2 fusion polypeptide complexes TCB 327, PAT-014, PAT-015, containing different masked peptides, the same digested fragments, and the same CD86 mutants, and their corresponding CD3xHer2 bispecific antibody TCB 160 to N87 tumor target cells before and after MTSP-1 digestion.

[0490] Figure 12C shows the SW480 killing effects of CD3xHer2 fusion polypeptide complexes TCB 327, PAT-014, PAT-015, containing different masked peptides, the same digested fragments, and the same CD86 mutants, before and after MTSP-1 digestion, and their corresponding CD3xHer2 bispecific antibody TCB 160.

[0491] Figure 12D shows the tolerance test of TCB 327 and TCB 160 in human CD3xHer2 double transgenic mice.

[0492] Figure 12E shows the pharmacokinetic analysis of TCB327 and TCB160 in mice.

[0493] Figure 12F shows the inhibitory effects of PAT-014 and the masked version on tumor growth in the PBMC-NUGC4 mouse model.

[0494] Figure 13A shows the antibody structures of CD3xHer2 fusion polypeptide complexes TCB 327, PAT-016, and PAT-017 containing the same masking peptide, different enzyme fragments, and the same CD86 mutant, and their corresponding CD3xHer2 bispecific antibody TCB 160.

[0495] Figure 13B shows the binding ability of CD3xHer2 fusion polypeptide complexes TCB 327, PAT-016, PAT-017, and their corresponding CD3xHer2 bispecific antibody TCB 160 to N87 tumor target cells before and after MTSP-1 digestion, which contain the same masking peptide, different digestion fragments, and the same CD86 mutant.

[0496] Figure 13C shows the SW480 killing effects of CD3xHer2 fusion polypeptide complexes TCB 327, PAT-016, PAT-017, and their corresponding CD3xHer2 bispecific antibody TCB 160, which contain the same masking peptide, different digestion fragments, and the same CD86 mutant, before and after MTSP-1 digestion.

[0497] Figure 14A shows the antibody structures of AN_PB_Ab-110, AN_PB_Ab-111, and AN_PB_Ab-112 of this application.

[0498] Figure 14B shows the SDS-PAGE electrophoresis results of AN_PB_Ab-110, AN_PB_Ab-111, and AN_PB_Ab-112 of this application.

[0499] Figure 14C shows the results of detecting the binding ability of AN_PB_Ab-110 and AN_PB_Ab-111 to human PBMCs before and after AN_PB_Ab-112 digestion.

[0500] Figure 14D shows the regulation of primary PBMC cells killing H358 tumor target cells by AN_PB_Ab-111 and AN_PB_Ab-110 before and after AN_PB_Ab-112 digestion.

[0501] Figure 14E shows the results of the CD3xEGFR fusion peptide complex of this application regulating the activation and expression of CD69 in primary PBMC cells in the absence of relevant tumor cells.

[0502] Figure 15A shows the antibody structures of AN_PB_Ab-17, AN_DL_Ab-028, and AN_DL_Ab-055 of this application.

[0503] Figure 15B shows the SDS-page electrophoresis diagrams of AN_PB_Ab-17, AN_DL_Ab-028, and AN_DL_Ab-055 of this application.

[0504] Figure 15C shows the results of detecting the binding ability of AN_DL_Ab-028 and AN_DL_Ab-055 to human PBMCs before and after AN_PB_Ab-17 digestion.

[0505] Figure 15D shows the regulation of primary PBMC cells killing SHP77 tumor target cells by AN_DL_Ab-028 and AN_DL_Ab-055 before and after AN_PB_Ab-17 digestion.

[0506] Figure 16A shows the structural diagrams of the CD3xHHLA2 trispecific antibodies AN_CHH_15 and AN_CHH_38 (containing CD3 binding domain masking function and CD86 variant peptide) and the CD3xHHLA2 bispecific antibodies AN_CHH_12 and AN_CHH_36 (not containing CD3 binding domain masking function) in this application.

[0507] Figure 16B shows the results of SDS-PAGE analysis of the expression of the mask-linker-CD3 / HHLA2 / CD86 and CD3 / HHLA2 fusion multifunctional peptides in this application.

[0508] Figure 16C shows the results of flow cytometry analysis of the binding levels of the mask-linker-CD3 / HHLA2 / CD86 and CD3 / HHLA2 fusion multifunctional peptides of this application to Jurkat E6-1 cells.

[0509] Figure 16D shows the kinetics of binding of the mask-linker-CD3 / HHLA2 / CD86 and CD3 / HHLA2 fusion multifunctional peptides of this application to human HHLA2 protein, as detected by OCTET.

[0510] Figure 16E shows the kinetics of binding of the mask-linker-CD3 / HHLA2 / CD86 and CD3 / HHLA2 fusion multifunctional peptides of this application to human CD3 protein using OCTET.

[0511] Figure 16F shows the results of regulating the killing of HCC827 (HHLA2-highly expressed) tumor cells by primary PBMC cells before and after MTSP1 restriction enzyme digestion with the mask-linker-CD3 / HHLA2 / CD86 fusion multifunctional peptide of this application (effect-target ratio of 1:1).

[0512] Figure 17A shows the structural diagrams of the CD3xCEA trispecific antibody AN_CEA_21 (containing CD3 binding domain masking function and CD86 variant peptide) and the CD3xCEA bispecific antibody AN_CEA_19 (not containing CD3 binding domain masking function) in this application.

[0513] Figure 17B shows the results of SDS-PAGE detection of the expression of the mask-linker-CD3 / CEA / CD86 and CD3 / CEA fusion multifunctional peptides in this application.

[0514] Figure 17C shows the results of flow cytometry analysis of the binding levels of the mask-linker-CD3 / CEA / CD86 and CD3 / CEA fusion multifunctional peptides of this application to MKN45 cells.

[0515] Figure 17D shows the kinetics of the binding of the mask-linker-CD3 / CEA / CD86 and CD3 / CEA fusion multifunctional peptides of this application to human CD3 protein using OCTET.

[0516] Figure 17E shows the results of regulating the killing of MKN45 (CEA-high expression) and HT-29 (CEA-low expression) tumor cells by the mask-linker-CD3 / CEA / CD86 fusion multifunctional peptide of this application before and after MTSP1 restriction enzyme digestion (effect-target ratio of 2:1). Detailed Implementation

[0517] The following specific embodiments illustrate the implementation of the invention. Those skilled in the art can easily understand other advantages and effects of the invention from the content disclosed in this specification.

[0518] Terminology Definition

[0519] In this invention, the term "regulation of T cell immune response" generally refers to the regulation of lymphocyte T cell function by the multifunctional fusion polypeptide disclosed in this application. For example, it can also be extended to the effects of any other related T cell regulators, such as influencing T cell NFAT transcription factor expression, secretion of cytokines IL-2, IFN-γ, TNFα, and Granzyme B, cell proliferation, and cell killing of target cells, including tumor cells, after T cell treatment. The T cells can be extended to T cell lines and / or primary T cells, including but not limited to CD4 T cells and CD4 T cell subsets Th1, Th2, Th9, Th17, TFH, and / or Treg cells; it also includes CD8 T cells, encompassing but not limited to tumor-infiltrating CD8 T cells, effector CD8 T cells, and immune memory CD8 T cells.

[0520] In this invention, the term "CD3" refers to the CD3 protein on T cells, generally referring to a protein complex belonging to the immunoglobulin superfamily, comprising four subunits: CD3ε, CD3δ, CD3γ, and CD3ζ. The CD3 protein plays a crucial role in the T cell receptor (TCR) complex, promoting T cell signal transduction and activation. Specifically, the CD3 protein interacts with the β and α chains of the TCR-CD3 complex, forming the core structure for signal transduction. As used herein, the term "CD3" refers to any naturally occurring CD3 from any human source. The term also encompasses "full-length" and unprocessed proteins, as well as any form of protein or one or more CD3 chains (peptides) derived from cell-processed proteins (e.g., mature peptides). The term also encompasses naturally occurring variants and isotypes of CD3, such as splice variants or allelic variants. For example, www.uniprot.org / uniprot / P04234, www.uniprot.org / uniprot / P07766, and www.uniprot.org / uniprot / P09693 provide descriptions of CD3γ chains, CD3δ chains, and CD3ε chains and sequences.

[0521] The antibodies described herein can be derived from any animal source, including birds and mammals, including primates. Preferably, the antibodies are antibodies from humans, baboons, rhesus monkeys, cynomolgus monkeys, mice, donkeys, rabbits, goats, guinea pigs, camels, llama, horses, or chickens.

[0522] In this invention, the term "anti-CD3 antibody" includes antibodies that specifically recognize a single CD3 subunit (e.g., B, δ, γ, or ζ) and their antigen-binding fragments, as well as antibodies that specifically recognize a dimer complex of two CD3 subunits (e.g., γ / ε, δ / ε, and ζ / ζ CD3 dimers) and their antigen-binding fragments. For example, monoclonal antibodies, including human, humanized, chimeric, or mouse antibodies, target the CD3 receptor in the T cell antigen receptor of mature T cells. For instance, an anti-CD3 antibody could be a CD3SP34 antibody or its antigen-binding fragment.

[0523] In this invention, the term "tumor-associated antigen (TAA)" refers to antigen molecules that are not specific to a particular tumor and are also present on other tumor cells or normal cells. Tumor-associated antigens used for clinical diagnosis include embryonic proteins, glycoprotein antigens, squamous cell antigens, etc. Tumor-associated antigens are not specific to tumor cells, but differ only in quantity during proliferation. Normal cells also synthesize trace amounts, hence the term "associated antigen." Tumors of the same tissue type induced by the same carcinogen may possess the same tumor-associated antigens in different individuals.

[0524] In this invention, bispecific antibodies (BsAbs) are artificial antibodies prepared through cell fusion, recombinant DNA, protein engineering, and other techniques. They can simultaneously or sequentially bind specifically to two antigens or two different epitopes of the same antigen. BsAbs can recognize and bind to two different antigens or antigenic epitopes, thus enabling them to connect effector cells such as immune cells or cytokines to tumor cells, thereby enhancing the killing effect on target cells. They can also bind to different antigenic epitopes on the same tumor cell to enhance binding specificity while reducing adverse reactions caused by off-target toxicity; or bind to different immunomodulatory antigens on the same immune cell to simultaneously block / activate downstream immune signaling pathways, inhibiting or activating immune cells. Theoretically, such bifunctional recombinant antibodies, as drugs for treating tumors, have higher efficacy than monoclonal antibody drugs, achieving a synergistic effect ("1+1>2").

[0525] In this invention, a "multispecific antibody" is a class of antibodies possessing two different antigen-binding properties, capable of simultaneously binding to two different targets. This antibody structure typically consists of two separate antibody-binding fragments that can bind two different antigens within the same molecule, or two identical antigens at different sites. In therapeutic applications, the advantage of multispecific antibodies lies in their ability to act on two different targets simultaneously or enhance the same target, strengthening their potential in treating various diseases. Compared to traditional bispecific antibodies, multispecific antibodies can effectively enhance therapeutic effects, overcome the limitations of single-target therapy, and possess stronger targeting specificity. In this application, multispecific antibodies, by introducing two different antigen-binding sites into their structure, achieve specific recognition of tumor cells and activation of T cells, thereby effectively enhancing the anti-tumor immune response.

[0526] In this invention, the term "CD86" generally refers to a class of molecules that activate cells. For example, in this application, CD86 includes its full length, variants, and / or functionally active fragments. In this application, CD86 can represent a polypeptide or fragment thereof that has at least about 85% amino acid identity with the protein encoded by the NCBI accession number Gene ID: 942 gene and has CD28 (the protein encoded by the NCBI accession number Gene ID: 940 gene) and / or CTLA4 (the protein encoded by the NCBI accession number Gene ID: 1493 gene). An exemplary human CD86 amino acid sequence (SEQ ID NO: 1) is provided below. The terms "CD86 extracellular region," "CD86 extracellular domain," and "CD86 ECD region" refer to the amino acid sequence of the domain in the extracellular region of the CD86 protein, which has at least about 85% amino acid identity and has CD28 and / or CTLA4 binding activity. An exemplary CD86 extracellular region amino acid sequence (SEQ ID NO: 2) is provided below. The terms "CD86 extracellular domain IgV domain" and "CD86 ECD region" refer to the amino acid sequence of the domain in the extracellular region of the CD86 protein, which has at least about 85% amino acid identity and has CD28 and / or CTLA4 binding activity. "IgV domain" refers to an amino acid sequence of an IgV-like domain in the extracellular region of the CD86 protein, with at least about 85% amino acid identity, and a polypeptide or fragment thereof having CD28 and / or CTLA4 binding activity. An exemplary amino acid sequence of the CD86 extracellular domain IgV domain is provided below (SEQ ID NO: 3). The CD86 extracellular domain disclosed in this invention, or the number of CD86 extracellular domain IgV domains in tandem, is not limited to the number shown in the example. Any tandem combination containing this functional domain can be considered within the scope of this invention.

[0527] In this invention, the term "CD80" refers to a polypeptide or fragment thereof that has at least about 85% amino acid identity with the protein encoded by the NCBI accession number Gene ID:941 and has binding activity for CD28 (the protein encoded by the NCBI accession number Gene ID:940) and / or CTLA4 (the protein encoded by the NCBI accession number Gene ID:1493). An exemplary human CD80 amino acid sequence (SEQ ID NO: 1) is provided below. The term "CD80 extracellular region" refers to a polypeptide or fragment thereof that has at least about 85% amino acid identity with the domain in the extracellular region of the CD80 protein and has binding activity for CD28 and / or CTLA4. An exemplary "CD80 extracellular region amino acid sequence" (SEQ ID NO: 294) is provided below. The number of tandem sequences disclosed in this invention is not limited to the number shown in the examples, and any tandem combination containing this functional domain is considered to be within the scope of this invention.

[0528] In this invention, the term "masking" refers to the process of using a specific amino acid sequence (i.e., a masking peptide) to spatially or conformally block a target domain, particularly the CD3-binding domain, thereby affecting the binding of that domain to its natural ligand or target under normal physiological conditions and inhibiting its activity or function. This masking effect is generally achieved through steric hindrance, conformational modulation, and conditional unmasking.

[0529] In this invention, the term "masking peptide" refers to a molecule capable of "shielding" or inhibiting the function of antibodies or other therapeutic proteins through a specific amino acid sequence or peptide segment. The role of a masking peptide is to control and regulate protein function by binding to a target protein or antibody under specific conditions, thereby preventing its activity. In this application, the primary function of the masking peptide is to inhibit the non-specific activation of the CD3 domain in normal tissues. In the absence of tumor signals, the masking peptide, by binding to the CD3 domain, prevents premature activation of T cells, reducing potential overreaction of the immune system or cytokine storm.

[0530] In this invention, a "specific linker" is a molecular structure used to connect two molecules (such as proteins, peptides, or drugs). In peptides, antibodies, or immunotherapy, specific linkers are often used to connect multiple functional units or domains, enabling them to exert synergistic effects under specific conditions. In this application, the specific linker connects a masking peptide to a CD3 domain and, through a sequence containing specific cleavage sites, ensures that CD3 function is activated only in the tumor microenvironment; therefore, it is also referred to as an "enzyme-cleaved linker" in this invention. These specific linkers are typically designed to be cleaved by specific proteases (such as MMPs, FAP, uPA, etc.) in the tumor microenvironment, thereby achieving the regulated release of functional proteins. The introduction of specific linkers can effectively control the spatiotemporal specificity of therapeutic proteins, enabling them to function at the target site or under the target conditions, while reducing the impact on normal tissues. In this application, specific proteases in the tumor microenvironment can cleave the linker, releasing the masking peptide, thereby restoring CD3 function and achieving tumor-targeted activation of T cells.

[0531] In this invention, the term "fusion polypeptide" generally refers to a polypeptide obtained by fusing two or more proteins or polypeptides. In this application, "fusion polypeptide," "fusion polypeptide complex," and "fusion protein" can be used interchangeably. A fusion polypeptide may comprise a fusion polypeptide complex. Fusion polypeptides can be artificially prepared using recombinant DNA technology. For example, genes or nucleic acid molecules encoding the two or more proteins or polypeptides can be linked together to form a fusion gene or fused nucleic acid molecule that encodes the fusion polypeptide. Translation of the fusion gene can produce a single polypeptide that may possess the properties of at least one, or even each, of the two or more proteins or polypeptides before fusion.

[0532] In this invention, the term "multifunctional fusion polypeptide" generally refers to a polypeptide or protein formed by the fusion of polypeptides or their domains from one or more sources. The anti-CD3 antibody is linked via the linker to a functional fusion polypeptide comprising at least the CD86 extracellular domain and at least the functional domain for binding tumor-associated antigen (TAA).

[0533] In this invention, the term "antibody-associated antigen-binding fragment" generally refers to an amino acid fragment in an antibody responsible for specific binding to an antigen. This fragment can be a key differentiator in the antibody molecule, also referred to as an antigen-binding domain, or an "epitope" or "antigen determinant." The antigen-binding domain typically consists of a variable region (VH) of the antibody heavy chain and a variable region (VL) of the antibody light chain; however, it does not necessarily include both. The antigen-binding domains of the antibodies disclosed in this application are not limited to the conventional VH and VL domains, but also include antigen-binding domains contained in any other type of antibody, but not limited to recombinant antibodies, single-domain antibodies, heavy-chain antibodies, chimeric antibodies, bispecific antibodies, and other unconventional antibodies and combinations thereof.

[0534] Furthermore, the anti-CD3 antibodies disclosed in this invention are not limited to traditional natural antibodies, but should include any other type of antibody with anti-CD3 antibody properties, but are not limited to, for example, recombinant antibodies, single-domain antibodies, heavy chain antibodies, chimeric antibodies, bispecific antibodies and other unconventional antibodies and combinations thereof.

[0535] The term "antibody fragment" or "antigen-binding fragment" as used in this invention refers to a portion of an antibody, such as F(ab')2, F(ab)2, Fab', Fab, Fv, scFv, VHH, etc. Regardless of structure, antibody fragments that bind to the same antigen are considered complete antibodies. The term "antibody fragment" includes aptamers, aptamer enantiomers, and dimeric antibodies. The term "antibody fragment" also includes any synthetic or genetically modified protein that, like an antibody, can bind to a specific antigen to form a complex.

[0536] In this invention, the term "Fab" generally refers to an antibody fragment composed of VL, VH, CL and CH1 domains.

[0537] In this invention, the term "Fab'" generally refers to an antibody fragment having several additional residues at the carboxyl terminus of the CH1 domain compared to the Fab fragment. For example, Fab' may include one or more cysteine ​​residues from the antibody hinge region.

[0538] In this invention, the term "F(ab)2" generally refers to an antigen-binding fragment obtained from a pair of Fab fragments linked by cysteine.

[0539] In this invention, the term "dAb fragment" generally refers to an antibody fragment composed of VH domains (Ward et al., Nature 341:544 546 (1989)).

[0540] In this invention, the term "complementary determinant region (CDR)" usually refers to the three hypervariable regions (HVR) of the light chain variable region (VL) and the heavy chain variable region (VH). Because these regions can form precise complementarity with antigenic determinants in spatial structure, the hypervariable regions are also called complementary determinant regions.

[0541] In this invention, the term "Fv fragment" generally refers to an antibody fragment consisting of the VL and VH domains of a single arm of an antibody.

[0542] In this invention, the term "scFv" generally refers to a molecule composed of the variable regions of the antibody heavy chain and the variable regions of the light chain linked by a short peptide linker, also known as a single-chain antibody.

[0543] In this invention, the term "single-domain antibody" generally refers to an antibody consisting only of the heavy chain variable region, also known as "VHH" or "nanobody".

[0544] In this invention, the term "immunoglobulin" refers to an antibody comprising an amino acid fragment that specifically binds to an antigen and a constant region fragment. The antigen-specific binding region is the segment in the immunoglobulin that determines key differences; it can also be called an antigen-binding domain, or an "epitope" or "antigen determinant." The antigen-binding domain typically consists of the antibody heavy chain variable region (VH) and the antibody light chain variable region (VL). However, it does not necessarily include both. The antigen-binding domain of the antibody disclosed in this invention is not limited to the conventional VH and VL domain, but also includes the antigen-binding domains contained in any other type of antibody, but not limited to, recombinant antibodies, single-domain antibodies, heavy chain antibodies, chimeric antibodies, bispecific antibodies, and other unconventional antibodies and combinations thereof. The constant region refers to the common structural region of the immunoglobulin, comprising the antibody light chain constant region and heavy chain constant region.

[0545] In this invention, the term "immunoglobulin Fc domain" generally refers to the Fc fragment formed from one Fc fragment and two identical Fab fragments after conventional antibody IgG is hydrolyzed by papain. The Fc domain may contain the CH2, CH3, and hinge regions of the antibody heavy chain. Conventional Fc fragments have the function of binding to Fc fragment receptors to mediate related biological effects. Site-specific mutations can alter their binding ability to the corresponding target receptors, thus affecting their biological function. The immunoglobulin Fc domain disclosed in this application should include, but is not limited to, conventional Fc fragments and any other forms of Fc mutants. The biological functions that the immunoglobulin Fc domain can provide include, but are not limited to, prolonging half-life, improving molecular stability, facilitating the expression and detection of fusion proteins, mediating transplacental and mucosal barriers, mediating antibody-dependent cell-mediated cytotoxicity (ADCC), mediating inflammatory responses, mediating antibody-dependent cell-mediated phagocytosis (ADCP), mediating complement-dependent cytotoxicity (CDC), mediating dendritic cell (DC) maturation, regulating cytokine secretion, and regulating B cell proliferation and differentiation. The following provides exemplary Fc domains of human immunoglobulin IgG1 and human immunoglobulin IgG4.

[0546] In this invention, Fab-Fc, scFv-Fc, and VHH-Fc are included in the scope of "heavy chain" or "antibody heavy chain" as referred to in this invention.

[0547] In this invention, the terms "peptide" and "protein" have the same meaning and are used interchangeably. Furthermore, in this invention, amino acids are generally represented by single-letter and three-letter abbreviations known in the art. For example, alanine can be represented by A or Ala. The proteins, peptides, and / or amino acid sequences involved in this application should also be understood to include at least the following range: variants or homologs that have the same or similar functions as the said protein or peptide.

[0548] In this invention, the term "mutant" or "variant" generally refers to a peptide substantially similar to the peptide in question, and may be a protein or polypeptide whose amino acid sequence has been substituted, deleted, or added with one or more amino acids. For example, the functional variant may comprise a protein or polypeptide that has undergone amino acid alterations through substitution, deletion, and / or insertion of at least one, such as 1-30, 1-20, or 1-10, or even 1, 2, 3, 4, or 5 amino acids. The functional variant may substantially retain the biological properties of the protein or polypeptide prior to the alteration (e.g., substitution, deletion, or addition). For example, the functional variant may retain at least 60%, 70%, 80%, 90%, or 100% of the biological activity (e.g., antigen-binding capacity) of the protein or polypeptide prior to the alteration. For example, the substitution may be a conserved substitution.

[0549] In this invention, the homolog can be a protein or polypeptide having at least about 85% (e.g., having at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99% or higher) sequence homology with the amino acid sequence of the protein and / or the polypeptide (e.g., an antibody that specifically binds to the protein or a fragment thereof).

[0550] In this invention, homology generally refers to the similarity, resemblance, or association between two or more sequences. The "sequence homology percentage" can be calculated as follows: Two sequences to be aligned are compared in a comparison window, and the number of positions in the two sequences containing the same nucleic acid bases (e.g., A, T, C, G, I) or the same amino acid residues (e.g., Ala, Pro, Ser, Thr, Gly, Val, Leu, Ile, Phe, Tyr, Trp, Lys, Arg, His, Asp, Glu, Asn, Gln, Cys, and Met) is determined to obtain the number of matching positions. The number of matching positions is divided by the total number of positions in the comparison window (i.e., the window size), and the result is multiplied by 100 to produce the sequence homology percentage. Alignment for determining the sequence homology percentage can be performed in various ways known in the art, for example, using publicly available computer software such as BLAST, BLAST-2, ALIGN, or Megalign (DNASTAR) software. Those skilled in the art can determine suitable parameters for aligning sequences, including any algorithm required to achieve maximum alignment across the full-length sequence being compared or within the target sequence region. The homology can also be determined, but is not limited to, by FASTA and BLAST.

[0551] Normally, in a polypeptide chain, an amino group is linked to another carboxyl group to form a chain. However, at the two ends of a protein, there are amino acid residues that have not formed peptide bonds, namely the polypeptide chain end carrying a free amino group and the polypeptide chain end carrying a carboxyl group, respectively. In this application, the term "N-terminus" generally refers to the end of the polypeptide chain where the amino acid residue carries a free amino group. In this application, the term "C-terminus" generally refers to the end of the polypeptide chain where the amino acid residue carries a free carboxyl group.

[0552] In this invention, the term "nucleic acid molecule" generally refers to any length of isolated nucleotide, deoxyribonucleotide, or ribonucleotide or analogue thereof, isolated from its natural environment or synthesized artificially.

[0553] In this invention, the term "vector" refers to a nucleic acid delivery vehicle that can insert a polynucleotide encoding a protein therein and enable the protein to be expressed.

[0554] In this invention, the term "linker" generally refers to a linker molecule that connects one or more polypeptides or their domains. For example, a linker can be conformationally flexible, a short peptide chain formed by the combination of amino acid Gly (G) and Ser (S) residues, wherein the ratio of the number of amino acid Gly to the number of amino acid Ser can be ≥1. The linkers disclosed in this application can be extended to any short peptide having this characteristic. The following provides exemplary linker amino acid sequences including but not limited to GGGGS (SEQ ID NO: 5), GGGGSGGGGS (SEQ ID NO: 6), GGGGSGGGGSGGGGS (SEQ ID NO: 7), GGGGSGGGGSGGGGSGGGS (SEQ ID NO: 8), GGGGSGGGGSGGGGSGGGSG (SEQ ID NO: 9), and GGGGSGGGS (SEQ ID NO: 10).

[0555] In this invention, the term "enzyme-cleavable linker" generally refers to a linker containing a protease-cleavable fragment, wherein the protease-cleavable fragment can be specifically recognized and cleaved by the corresponding protease. The proteases include, but are not limited to, matrix metalloproteinases, urokinase, transmembrane serine proteases, transforming factor TGFβ, plasminogen, glucosinolates, human liver collagen, human α-2-macroglobulin (α2M), and human PZP α-2-macroglobulin-like protein (PZP), etc.

[0556] In this invention, the term "amino acid mutation" generally refers to amino acid substitution, deletion, insertion, and modification. Any combination of substitution, deletion, insertion, and modification can be performed to achieve the final construct, as long as the final construct possesses the desired properties.

[0557] In one implementation, the amino acid mutation is a substitution. The term "amino acid mutation at a position" refers to the substitution or deletion of a specified residue or the insertion of at least one amino acid residue adjacent to a specified residue. The amino acid substitution can be conserved or non-conserved. For example, "A13I" can represent the substitution of alanine (A, Ala) at position 13 with isoleucine (I, Ile).

[0558] In this invention, the term "active fragment" generally refers to a nucleic acid or amino acid fragment or variant that has a certain biological activity or function. For example, a functionally active fragment may retain or partially retain the ability of a full-length protein to bind to another molecule. In this invention, "active fragment," "functionally active fragment," or "active functional fragment" are generally used interchangeably.

[0559] In this invention, "CD86 active fragment" refers to a polypeptide or fragment thereof that has binding activity with CD28 and / or CTLA4, including but not limited to features such as regulating T cell activity, activating the immune system, and anti-tumor activity.

[0560] The term "CD86 variant peptide" refers to a protein or peptide whose amino acid sequence has been modified by substitution, deletion, or addition of one or more amino acids. For example, the functional variant may comprise a protein or peptide with amino acid alterations resulting from substitution, deletion, and / or insertion of at least one, such as 1-30, 1-20, or 1-10, or even 1, 2, 3, 4, or 5 amino acids. The functional variant may substantially retain the biological characteristics of CD86 prior to the alteration (e.g., substitution, deletion, or addition). For example, the functional variant may retain at least 60%, 70%, 80%, 90%, or 100% of the biological activity (e.g., antigen-binding capacity) of the protein or peptide prior to the alteration. For example, the substitution may be a conserved substitution. "CD86 variant peptide" means an active fragment derived from the CD86 protein and possessing the functional characteristics of the CD86 protein, including but not limited to CD28 and / or CTLA4 binding activity.

[0561] The term "CD80 variant peptide" refers to a protein or peptide whose amino acid sequence has been altered by substitution, deletion, or addition of one or more amino acids. For example, the functional variant may comprise a protein or peptide with amino acid modifications resulting from substitution, deletion, and / or insertion of at least one, such as 1-30, 1-20, or 1-10, or even 1, 2, 3, 4, or 5 amino acids. The functional variant may substantially retain the biological characteristics of CD80 prior to the alteration (e.g., substitution, deletion, or addition). For example, the functional variant may retain at least 60%, 70%, 80%, 90%, or 100% of the biological activity (e.g., antigen-binding capacity) of the protein or peptide prior to the alteration. For example, the substitution may be a conserved substitution. "CD80 variant peptide" means an active fragment derived from the CD80 protein and possessing the functional characteristics of the CD80 protein, including but not limited to CD28 and / or CTLA4 binding activity.

[0562] The co-stimulatory receptors include, but are not limited to, ICOSL, CD40L, CD137L, OX40L, CD80, CD83, and CD86.

[0563] The antigen phagocytosis includes, but is not limited to, the phagocytosis of bacteria, viruses, proteins, polysaccharides, etc.

[0564] The cytokines include, but are not limited to, IL-1beta, TNFα, IFNγ, IL-6, and IL-12.

[0565] The chemokines include, but are not limited to, CCL1, CCL2, CCL3, CCL4, CCL5, CXCL1, CXCL2, CXCL3, CXCL4, and CXCL5.

[0566] In this invention, the term "comprising" generally means including the explicitly specified features, but does not exclude other elements.

[0567] In this invention, the term "about" generally refers to a variation within a range of 0.5% to 10% above or below a specified value, such as a variation within a range of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, or 10% above or below a specified value.

[0568] Invention Details

[0569] This invention provides a fusion polypeptide comprising a first domain, a second domain, and a third domain. The first domain binds CD3, the second domain binds a tumor-associated antigen (TAA), and the third domain binds CD28 and / or CTLA4. Furthermore, this invention may include a fourth domain that binds a TAA. This fourth domain may bind the same or different TAA as the second domain. The fourth domain may have the same or different sequence and / or structure as the second domain. The fourth domain may be present or absent. Furthermore, this invention may include a fifth domain that conditionally masks the CD3-binding domain in the first domain. This fifth domain may be present or absent. Furthermore, this invention may include a sixth domain that binds CD28 and / or CTLA4. This sixth domain may have the same or different sequence and / or structure as the third domain. The sixth domain may be present or absent.

[0570] The following is an exemplary, not limiting, description of the various structural domains of the present invention. For ease of understanding, Figures 1A-1E show exemplary, not limiting, structural diagrams of the first, second, third, fourth, and fifth structural domains of the functional fusion peptide of the present invention.

[0571] First structural domain

[0572] For example, the first structural domain can combine with CD3.

[0573] For example, the first domain contains an antibody or an antigen-binding fragment thereof.

[0574] For example, the first domain may comprise HCDR3 of the antibody heavy chain, which may comprise an amino acid sequence selected from the group consisting of: SEQ ID NO: 20, SEQ ID NO: 25, SEQ ID NO: 30, SEQ ID NO: 35, SEQ ID NO: 45, SEQ ID NO: 304, SEQ ID NO: 309, SEQ ID NO: 314, SEQ ID NO: 319.

[0575] For example, the first domain may comprise HCDR2 of the antibody heavy chain, which may comprise an amino acid sequence selected from the group consisting of: SEQ ID NO: 24, SEQ ID NO: 29, SEQ ID NO: 34, and SEQ ID NO: 44.

[0576] For example, the first domain may comprise HCDR1 of the antibody heavy chain, which may comprise an amino acid sequence selected from the group shown below: SEQ ID NO: 23, SEQ ID NO: 28, SEQ ID NO: 33, SEQ ID NO: 43.

[0577] For example, the first structural domain shown may include a heavy chain variable region VH of the antibody heavy chain, which may include an amino acid sequence selected from the group shown below: SEQ ID NO: 22, SEQ ID NO: 27, SEQ ID NO: 32, SEQ ID NO: 42, SEQ ID NO: 301, SEQ ID NO: 306, SEQ ID NO: 311, SEQ ID NO: 316.

[0578] For example, the first domain may comprise an antibody heavy chain, which may comprise an amino acid sequence selected from the group shown below: SEQ ID NO: 21, SEQ ID NO: 26, SEQ ID NO: 31, SEQ ID NO: 36, SEQ ID NO: 300, SEQ ID NO: 305, SEQ ID NO: 310, SEQ ID NO: 315.

[0579] For example, the first domain may comprise LCDR3 of an antibody light chain, which may comprise an amino acid sequence selected from the group consisting of: SEQ ID NO: 15, SEQ ID NO: 20, and SEQ ID NO: 41.

[0580] For example, the first domain may comprise LCDR2 of an antibody light chain, which may comprise an amino acid sequence selected from the group consisting of: SEQ ID NO: 14, SEQ ID NO: 19, and SEQ ID NO: 40.

[0581] For example, the first domain may comprise LCDR1 of an antibody light chain, which may comprise an amino acid sequence selected from the group shown below: SEQ ID NO: 13, SEQ ID NO: 18, SEQ ID NO: 39.

[0582] For example, the first domain may include a light chain variable region VL of the antibody light chain, which may include an amino acid sequence selected from the group consisting of: SEQ ID NO: 12, SEQ ID NO: 17, and SEQ ID NO: 38.

[0583] For example, the first domain may comprise an antibody light chain, which may comprise an amino acid sequence selected from the group shown below: SEQ ID NO: 11, SEQ ID NO: 16.

[0584] In one embodiment, the fusion polypeptide includes a first domain comprising an antibody, an antigen-binding fragment thereof, or a variant thereof selected from the group consisting of: antibody OKT3, antibody UCHT1, antibody SP34, Blinatumamab, Tebentafusp, Mosunetuzumab, and Teclistamab.

[0585] In one embodiment of the fusion polypeptide, the first domain may comprise an antibody SP34 mutant or its antigen-binding site.

[0586] In one embodiment of the fusion polypeptide, the first domain may comprise an antibody SP34 mutant or its antigen-binding site, the mutation occurring in the CDR region.

[0587] In one embodiment of the fusion polypeptide, the first domain may comprise an antibody SP34 mutant or its antigen-binding site, the mutation occurring in the HCDR region, the mutation comprising one or more amino acid site mutations selected from the group shown in SEQ ID NO: 22 of the antibody SP34 heavy chain variable region: T31D, R50K, N100D, N97S, F100fH, S100aA, V100cT.

[0588] In one embodiment of the fusion polypeptide, the first domain may comprise an antibody SP34 mutant or its antigen-binding site, the mutation occurring in the LCDR region, the mutation comprising one or more amino acid site mutations selected from the group shown in SEQ ID NO: 12 of the antibody SP34 light chain variable region: N94Q.

[0589] For example, the antibody may be selected from immunoglobulin antibodies, recombinant antibodies, chimeric antibodies, heavy chain antibodies, single-domain antibodies and / or bispecific antibodies; the antigen-binding fragment may be selected from Fab, Fab', Fv, F(ab)2, F(ab')2, scFv, di-scFv, VHH and / or dAb.

[0590] For example, the first domain includes a single-chain immunoglobulin domain.

[0591] For example, the single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

[0592] For example, the first domain includes the Fc domain of a single-chain immunoglobulin IgG antibody, wherein the Fc domain of the single-chain immunoglobulin IgG antibody includes a human IgG1 Fc domain, a human IgG2 Fc domain, a human IgG3 Fc domain, a human IgG4 Fc domain, a mouse IgG1 Fc domain, a mouse IgG2a Fc domain, a mouse IgG2b Fc domain, or a mouse IgG3 Fc domain.

[0593] For example, the first domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences, and contains any amino acid sequence selected from the following group: SEQ ID NO: 3, SEQ ID NO: 4.

[0594] For example, the first structural domain CH2 is located between the scFv fragment and the CH3 structural domain. On the other hand, the first structure does not include the CH1 structural domain.

[0595] For example, the first domain does not contain light chains.

[0596] Second domain / fourth domain

[0597] For example, the second or fourth domain can bind to one or more of the targets shown in the following group: PD-L1, PD-L2, VEGF, VEGFR, FGFR, HER2, HGFR, PIP-LAR, CD44, CD147, TfR, CDCP1, α6β4, α6β3, Trop2, HHLA2, GCC, 5T4, EpCAM, GPRC5D, BCMA, CD19, CD20, HER-2neu, DLL1, DLL3, B7H3, HER-3, HER-4, EGFR, PSMA, CEA, MUC-1 (mucin), MUC2, MUC3, MUC4, MUC5AC, MUC5B, MUC7, CD123, CD33, CD30, CD38, PTK7, EphA2, NKG2A, Nkp36 and / or Tim3.

[0598] For example, the second or fourth domain binds to proteins or tumor antigens overexpressed on tumor cells relative to the corresponding non-tumor cells, such as CD20, Her2, PD-L1, HHLA2, GCC, EGFR, DLL3 and / or B7H3, 5T4 and / or CEA.

[0599] For example, the second or fourth domain may comprise HCDR3 of the antibody heavy chain, which may comprise an amino acid sequence selected from the group consisting of: SEQ ID NO: 50, SEQ ID NO: 61, SEQ ID NO: 66, SEQ ID NO: 71, SEQ ID NO: 76, SEQ ID NO: 81, SEQ ID NO: 86, SEQ ID NO: 96, SEQ ID NO: 2009, SEQ ID NO: 2014.

[0600] For example, the second or fourth domain may comprise HCDR2 of the antibody heavy chain, which may comprise an amino acid sequence selected from the group consisting of: SEQ ID NO: 49, SEQ ID NO: 60, SEQ ID NO: 65, SEQ ID NO: 70, SEQ ID NO: 75, SEQ ID NO: 80, SEQ ID NO: 85, SEQ ID NO: 95, SEQ ID NO: 2008, SEQ ID NO: 2013.

[0601] For example, the second or fourth domain may comprise HCDR1 of the antibody heavy chain, which may comprise an amino acid sequence selected from the group consisting of: SEQ ID NO: 48, SEQ ID NO: 59, SEQ ID NO: 64, SEQ ID NO: 69, SEQ ID NO: 74, SEQ ID NO: 79, SEQ ID NO: 84, SEQ ID NO: 94, SEQ ID NO: 2007, SEQ ID NO: 2012.

[0602] For example, the second or fourth domain shown may include a heavy chain variable region VH of the antibody heavy chain, which may contain an amino acid sequence selected from the group shown: SEQ ID NO: 47, SEQ ID NO: 58, SEQ ID NO: 63, SEQ ID NO: 68, SEQ ID NO: 73, SEQ ID NO: 83, SEQ ID NO: 93, SEQ ID NO: 2006, SEQ ID NO: 2011.

[0603] For example, the second or fourth domain may comprise an antibody heavy chain, which may comprise an amino acid sequence selected from the group consisting of: SEQ ID NO: 46, SEQ ID NO: 57, SEQ ID NO: 62, SEQ ID NO: 67, SEQ ID NO: 72, SEQ ID NO: 77, SEQ ID NO: 82, SEQ ID NO: 92, SEQ ID NO: 2000, SEQ ID NO: 2010.

[0604] For example, the second or fourth domain may comprise LCDR3 of an antibody light chain, which may comprise an amino acid sequence selected from the group consisting of: SEQ ID NO: 56, SEQ ID NO: 91, SEQ ID NO: 2005.

[0605] For example, the second or fourth domain may comprise LCDR2 of the antibody light chain, which may comprise an amino acid sequence selected from the group consisting of: SEQ ID NO: 55, SEQ ID NO: 90, SEQ ID NO: 2004.

[0606] For example, the second or fourth domain may comprise LCDR1 of an antibody light chain, which may comprise an amino acid sequence selected from the group consisting of: SEQ ID NO: 54, SEQ ID NO: 89, SEQ ID NO: 2003.

[0607] For example, the second or fourth domain may include a light chain variable region VL of the antibody light chain, which may include an amino acid sequence selected from the group consisting of: SEQ ID NO: 53, SEQ ID NO: 88, SEQ ID NO: 2002.

[0608] For example, the second or fourth domain may comprise an antibody light chain, which may comprise an amino acid sequence selected from the group consisting of: SEQ ID NO: 52, SEQ ID NO: 87.

[0609] For example, the second or fourth domain comprises an amino acid sequence selected from the group consisting of: SEQ ID NO: 46, SEQ ID NO: 47, SEQ ID NO: 52, SEQ ID NO: 57, SEQ ID NO: 62, SEQ ID NO: 63, SEQ ID NO: 67, SEQ ID NO: 68, SEQ ID NO: 72, SEQ ID NO: 73, SEQ ID NO: 77, SEQ ID NO: 78, SEQ ID NO: 82, SEQ ID NO: 83, SEQ ID NO: 87, SEQ ID NO: 92, SEQ ID NO: 2000, SEQ ID NO: 2001, SEQ ID NO: 2010, SEQ ID NO: 2011.

[0610] The fourth structural domain may be associated with the same or different TAAs as the second structural domain, may have the same or different sequences and / or structures, and may or may not exist. This is also true in the more specific descriptions below, and will not be repeated here.

[0611] For example, the second or fourth domain may contain HCDR3, HCDR2 and HCDR1 of the antibody heavy chain, wherein HCDR1, HCDR2 and HCDR3 may contain amino acid sequences as shown in SEQ ID NO: 59, SEQ ID NO: 60 and SEQ ID NO: 61, respectively.

[0612] For example, the second or fourth domain may comprise LCDR3, LCDR2, and LCDR1 of the antibody light chain, wherein LCDR1, LCDR2, and LCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 54, SEQ ID NO: 55, and SEQ ID NO: 56, respectively.

[0613] For example, the second or fourth domain may comprise HCDR3, HCDR2, HCDR1 of the antibody heavy chain and LCDR3, LCDR2, and LCDR1 of the antibody light chain, wherein HCDR1, HCDR2, and HCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 59, SEQ ID NO: 60, and SEQ ID NO: 61, respectively, and LCDR1, LCDR2, and LCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 54, SEQ ID NO: 55, and SEQ ID NO: 56, respectively.

[0614] For example, the second or fourth domain may include a heavy chain variable region VH of the antibody heavy chain, which may contain an amino acid sequence as shown in SEQ ID NO: 58, and the second domain may include a light chain variable region VL of the antibody light chain, which may contain an amino acid sequence as shown in SEQ ID NO: 52.

[0615] For example, the second or fourth domain may be Trastuzumab or its antigen-binding fragment.

[0616] For example, the second or fourth domain can be a single-domain antibody.

[0617] For example, the second or fourth domain may comprise CDR3, CDR2, and CDR1 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 48, SEQ ID NO: 49, and SEQ ID NO: 50, respectively.

[0618] For example, the second or fourth domain may contain the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO: 47.

[0619] For example, the second or fourth domain may be Her2-VHH or its antigen-binding fragment.

[0620] For example, the second or fourth domain contains a single-chain immunoglobulin domain.

[0621] For example, the single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

[0622] For example, the second and / or fourth domains may contain the Fc domain of a single-chain immunoglobulin IgG antibody, wherein the Fc domain of the single-chain immunoglobulin IgG antibody may contain a human IgG1 Fc domain, a human IgG2 Fc domain, a human IgG3 Fc domain, a human IgG4 Fc domain, a mouse IgG1 Fc domain, a mouse IgG2a Fc domain, a mouse IgG2b Fc domain, or a mouse IgG3 Fc domain.

[0623] For example, the second or fourth domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences and contains any amino acid sequence selected from the following group: SEQ ID NO: 3, SEQ ID NO: 4.

[0624] For example, the second or fourth domain may comprise CDR3, CDR2, and CDR1 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 69, SEQ ID NO: 70, and SEQ ID NO: 71, respectively.

[0625] For example, the second or fourth domain may contain the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO: 68.

[0626] For example, the second or fourth domain may be PDL1-VHH-Nb02 NM-01 or its antigen-binding fragment, wherein PDL1-VHH-Nb02 NM-01 is derived from WO 2019 / 052508 A1.

[0627] For example, the second and / or fourth domains contain single-chain immunoglobulin domains.

[0628] For example, the single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

[0629] For example, the second and / or fourth domains may contain the Fc domain of a single-chain immunoglobulin IgG antibody, wherein the Fc domain of the single-chain immunoglobulin IgG antibody may contain a human IgG1 Fc domain, a human IgG2 Fc domain, a human IgG3 Fc domain, a human IgG4 Fc domain, a mouse IgG1 Fc domain, a mouse IgG2a Fc domain, a mouse IgG2b Fc domain, or a mouse IgG3 Fc domain.

[0630] For example, the second and / or fourth domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences, and contains any amino acid sequence selected from the following group: SEQ ID NO: 3, SEQ ID NO: 4.

[0631] For example, the second or fourth domain may comprise CDR3, CDR2, and CDR1 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 79, SEQ ID NO: 80, and SEQ ID NO: 81, respectively.

[0632] For example, the second or fourth domain may contain the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO: 78.

[0633] For example, the second or fourth domain may be h5T4 VHH-HuNb1 40 or its antigen-binding fragment, wherein h5T4 VHH-HuNb1 40 is derived from CN117624366A.

[0634] For example, the second or fourth domain contains a single-chain immunoglobulin domain.

[0635] For example, the single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

[0636] For example, the second or fourth domain may contain the Fc domain of a single-chain immunoglobulin IgG antibody, wherein the Fc domain of the single-chain immunoglobulin IgG antibody may contain a human IgG1 Fc domain, a human IgG2 Fc domain, a human IgG3 Fc domain, a human IgG4 Fc domain, a mouse IgG1 Fc domain, a mouse IgG2a Fc domain, a mouse IgG2b Fc domain, or a mouse IgG3 Fc domain.

[0637] For example, the second and / or fourth domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences, and contains any amino acid sequence selected from the following group: SEQ ID NO: 3, SEQ ID NO: 4.

[0638] For example, the second or fourth domain can bind to HHLA2 and contains an antibody or its antigen-binding fragment.

[0639] For example, the second or fourth domain may comprise CDR3, CDR2 and CDR1 of a single-domain antibody, wherein CDR1, CDR2 and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 1002, SEQ ID NO: 1003 and SEQ ID NO: 1004, respectively.

[0640] For example, the second and / or fourth domains may contain the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain the amino acid sequence shown in SEQ ID NO: 1001.

[0641] For example, the second or fourth domain contains a single-chain immunoglobulin domain.

[0642] For example, the single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

[0643] For example, the second or fourth domain may contain the Fc domain of a single-chain immunoglobulin IgG antibody, wherein the Fc domain of the single-chain immunoglobulin IgG antibody may contain a human IgG1 Fc domain, a human IgG2 Fc domain, a human IgG3 Fc domain, a human IgG4 Fc domain, a mouse IgG1 Fc domain, a mouse IgG2a Fc domain, a mouse IgG2b Fc domain, or a mouse IgG3 Fc domain.

[0644] For example, the second or fourth domain contains the Fc domain of single-chain human immunoglobulin IgG1 and has an L234A / L235A mutation.

[0645] For example, the second or fourth domain contains the Fc domain of single-stranded human immunoglobulin IgG1, has an L234A / L235A mutation, and has the necessary mutations in the knobs-into-holes (KiH) structure pair, such as: T366 on the CH3 domain of the Knob structure is replaced by a relatively large amino acid residue, such as tyrosine (Y) or tryptophan (W); or, T366 on the CH3 domain of the Hole structure is replaced by serine (S), L368 is replaced by a relatively small amino acid residue, such as alanine (A), and Y407 is replaced by a relatively small amino acid residue, such as threonine (T), alanine (A), or valine (V).

[0646] For example, the second or fourth domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences and contains any amino acid sequence selected from the following group: SEQ ID NO: 3, SEQ ID NO: 4.

[0647] For example, the second or fourth domain can be a single-domain antibody.

[0648] For example, the second or fourth domain may comprise CDR3, CDR2 and CDR1 of a single-domain antibody, wherein CDR1, CDR2 and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 2012, SEQ ID NO: 2013 and SEQ ID NO: 2014, respectively.

[0649] For example, the second or fourth domain may contain the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO: 2011.

[0650] For example, the second or fourth domain may be DLL3-VHH 52D04 or its antigen-binding fragment, wherein DLL3-VHH 52D04 is derived from patent CN113286817A.

[0651] For example, the second or fourth domain contains a single-chain immunoglobulin domain.

[0652] For example, the single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

[0653] For example, the second or fourth domain may contain the Fc domain of a single-chain immunoglobulin IgG antibody, wherein the Fc domain of the single-chain immunoglobulin IgG antibody may contain a human IgG1 Fc domain, a human IgG2 Fc domain, a human IgG3 Fc domain, a human IgG4 Fc domain, a mouse IgG1 Fc domain, a mouse IgG2a Fc domain, a mouse IgG2b Fc domain, or a mouse IgG3 Fc domain.

[0654] For example, the second or fourth domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences and contains any amino acid sequence selected from the following group: SEQ ID NO: 3, SEQ ID NO: 4.

[0655] For example, the second and / or fourth domains may comprise HCDR3, HCDR2, and HCDR1 of the antibody heavy chain, wherein HCDR1, HCDR2, and HCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 1011, SEQ ID NO: 1012, and SEQ ID NO: 1013, respectively.

[0656] For example, the second and / or fourth domains may comprise LCDR3, LCDR2, and LCDR1 of the antibody light chain, wherein LCDR1, LCDR2, and LCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 1015, SEQ ID NO: 1016, and SEQ ID NO: 1017, respectively.

[0657] For example, the second and / or fourth domains may comprise HCDR3, HCDR2, HCDR1 of the antibody heavy chain and LCDR3, LCDR2, and LCDR1 of the antibody light chain, wherein HCDR1, HCDR2, and HCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 1011, SEQ ID NO: 1012, and SEQ ID NO: 1013, respectively, and LCDR1, LCDR2, and LCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 1015, SEQ ID NO: 1016, and SEQ ID NO: 1017, respectively.

[0658] For example, the second or fourth domain may include a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain VH may include an amino acid sequence as shown in SEQ ID NO: 1010, and the second and / or fourth domain may include a light chain variable region VL of the antibody light chain, the antibody light chain VL may include an amino acid sequence as shown in SEQ ID NO: 1014.

[0659] For example, the second domain and / or the fourth domain may be CEA (Cergutuzumab) or its antigen-binding fragment, wherein CEA (Cergutuzumab) is derived from patent number US8642742B2.

[0660] For example, the second or fourth domain contains a single-chain immunoglobulin domain.

[0661] For example, the single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

[0662] For example, the second or fourth domain may contain the Fc domain of a single-chain immunoglobulin IgG antibody, wherein the Fc domain of the single-chain immunoglobulin IgG antibody may contain a human IgG1 Fc domain, a human IgG2 Fc domain, a human IgG3 Fc domain, a human IgG4 Fc domain, a mouse IgG1 Fc domain, a mouse IgG2a Fc domain, a mouse IgG2b Fc domain, or a mouse IgG3 Fc domain.

[0663] For example, the second or fourth domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences and contains any amino acid sequence selected from the following group: SEQ ID NO: 3, SEQ ID NO: 4.

[0664] For example, the second or fourth domain can be an SCFV single-chain antibody.

[0665] For example, the second or fourth domain may contain HCDR3, HCDR2 and HCDR1 of the antibody heavy chain, wherein HCDR1, HCDR2 and HCDR3 may contain amino acid sequences as shown in SEQ ID NO: 2007, SEQ ID NO: 2008 and SEQ ID NO: 2009, respectively.

[0666] For example, the second or fourth domain may comprise LCDR3, LCDR2 and LCDR1 of the antibody light chain, wherein LCDR1, LCDR2 and LCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 2003, SEQ ID NO: 2004 and SEQ ID NO: 2005, respectively.

[0667] For example, the second or fourth domain may comprise HCDR3, HCDR2, HCDR1 of the antibody heavy chain and LCDR3, LCDR2, and LCDR1 of the antibody light chain, wherein HCDR1, HCDR2, and HCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 2007, SEQ ID NO: 2008, and SEQ ID NO: 2009, respectively, and LCDR1, LCDR2, and LCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 2003, SEQ ID NO: 2004, and SEQ ID NO: 2005, respectively.

[0668] For example, the second or fourth domain may include a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain VH may include an amino acid sequence as shown in SEQ ID NO: 2006, and the second and / or fourth domain may include a light chain variable region VL of the antibody light chain, the antibody light chain VL may include an amino acid sequence as shown in SEQ ID NO: 2002-.

[0669] For example, the second or fourth domain may be necituzumab or its antigen-binding fragment.

[0670] For example, the second or fourth domain contains a single-chain immunoglobulin domain.

[0671] For example, the single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

[0672] For example, the second and / or fourth domains may contain the Fc domain of a single-chain immunoglobulin IgG antibody, wherein the Fc domain of the single-chain immunoglobulin IgG antibody may contain a human IgG1 Fc domain, a human IgG2 Fc domain, a human IgG3 Fc domain, a human IgG4 Fc domain, a mouse IgG1 Fc domain, a mouse IgG2a Fc domain, a mouse IgG2b Fc domain, or a mouse IgG3 Fc domain.

[0673] For example, the second or fourth domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences and contains any amino acid sequence selected from the following group: SEQ ID NO: 3, SEQ ID NO: 4.

[0674] For example, the second or fourth domain may contain HCDR3, HCDR2 and HCDR1 of the antibody heavy chain, wherein HCDR1, HCDR2 and HCDR3 may contain amino acid sequences as shown in SEQ ID NO: 94, SEQ ID NO: 95 and SEQ ID NO: 96, respectively.

[0675] For example, the second or fourth domain may comprise LCDR3, LCDR2, and LCDR1 of the antibody light chain, wherein LCDR1, LCDR2, and LCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 89, SEQ ID NO: 90, and SEQ ID NO: 91, respectively.

[0676] For example, the second or fourth domain may comprise HCDR3, HCDR2, HCDR1 of the antibody heavy chain and LCDR3, LCDR2, and LCDR1 of the antibody light chain, wherein HCDR1, HCDR2, and HCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 94, SEQ ID NO: 95, and SEQ ID NO: 96, respectively, and LCDR1, LCDR2, and LCDR3 may comprise amino acid sequences as shown in SEQ ID NO: 89, SEQ ID NO: 90, and SEQ ID NO: 91, respectively.

[0677] For example, the second or fourth domain may include a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain VH may include an amino acid sequence as shown in SEQ ID NO: 93, and the second domain may include a light chain variable region VL of the antibody light chain, the antibody light chain VL may include an amino acid sequence as shown in SEQ ID NO: 88.

[0678] For example, the second or fourth domain may be Mosunetuzumab or its antigen-binding fragment.

[0679] For example, the antibody with the second or fourth domain may be selected from immunoglobulin antibodies, recombinant antibodies, chimeric antibodies, heavy chain antibodies, single-domain antibodies, and / or bispecific antibodies; the antigen-binding fragment may be selected from Fab, Fab', Fv, F(ab)2, F(ab')2, scFv, di-scFv, VHH, and / or dAb.

[0680] For example, the second and / or fourth domains contain single-chain immunoglobulin domains.

[0681] For example, the single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

[0682] For example, the second and / or fourth domains may contain the Fc domain of a single-chain immunoglobulin IgG antibody, wherein the Fc domain of the single-chain immunoglobulin IgG antibody may contain a human IgG1 Fc domain, a human IgG2 Fc domain, a human IgG3 Fc domain, a human IgG4 Fc domain, a mouse IgG1 Fc domain, a mouse IgG2a Fc domain, a mouse IgG2b Fc domain, or a mouse IgG3 Fc domain.

[0683] For example, the second and / or fourth domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences, and contains any amino acid sequence selected from the following group: SEQ ID NO: 3, SEQ ID NO: 4.

[0684] Third or sixth domain CD86 / CD80

[0685] For example, the third or sixth domain can be combined with CD28 and / or CTLA4.

[0686] For example, the third or sixth domain contains CD86 or CD80 or a functionally active fragment thereof, or / and a variant of CD86 or CD80.

[0687] For example, the third or sixth domain is selected from the group consisting of CD86 or CD80 or their functionally active fragments derived from humans or mice.

[0688] For example, the third or sixth domain contains the IgV domain of CD86 or CD80 or a functionally active fragment thereof.

[0689] For example, the third or sixth domain contains the extracellular domain of CD86 or CD80 or a functionally active fragment thereof.

[0690] For example, the third or sixth domain contains a CD86 variant polypeptide, and the mutant contains an amino acid substitution mutation of humanized CD86.

[0691] For example, the CD86 mutant disclosed in PCT / CN2023 / 134527 is incorporated herein by reference.

[0692] For example, the third or sixth domain comprises a CD86 variant peptide, which comprises an IgV domain amino acid substitution mutant of CD86 and / or an extracellular domain amino acid substitution mutant of humanized CD86.

[0693] For example, the third or sixth domain comprises a CD86 variant polypeptide, the CD86 variant polypeptide comprising an IgV domain amino acid substitution mutant of CD86, the mutation site of the CD86 IgV domain amino acid substitution mutant comprising one, two, three, four, five or more amino acid site mutations selected from the group consisting of: A13I, A13L, A13F, A13M, Q25A, Q25I, Q25V, Q25F, Q25M, F33A, F33L, F33V, F33M, M60R, I89A, I89L, I89V, I89F, I89M, H90I, H90V, H90M, H90F.

[0694] For example, the third or sixth domain comprises a CD86 variant polypeptide, the CD86 variant polypeptide comprising an IgV domain amino acid substitution mutant of CD86, the amino acid substitution mutant comprising the combination shown below: Q25I / F33L / H90I, Q25V / F33L / H90I, Q25I / F33V / H90I, Q25V / F33V / H90I, Q25I / F33L / H90V, Q25 V / F33L / H90V, Q25I / F33V / H90V, Q25V / F33V / H90V, A13L / Q25I / F33L / H90I, A13I / Q25I / F33L / H 90I, A13L / Q25V / F33L / H90I, A13I / Q25V / F33L / H90I, Q25I / F33L / I89L / H90I, Q25I / F33L / M60R / H90I、Q25V / F33L / I89L / H90I、Q25V / F33L / M60R / H90I、Q25F / F33L / H90I、Q25I / F33L / H90F、Q 25I / F33A / H90I, Q25I / H90I, Q25I, H90I, Q25V / H90V, Q25V / H90I, Q25F / H90I, Q25F / H90V, A13F / Q25I / F33L / H90I, A13M / Q25I / F33L / H90I, Q25A / F33L / H90I, Q25M / F33L / H90I, Q25I / F33M / H90I, Q25I / F33L / I89V / H90I, Q25I / F33L / I89F / H90I, Q25I / F33L / I89M / H90I and Q25I / F33L / H90M.

[0695] For example, the third or sixth domain comprises a CD86 variant polypeptide, which comprises the CD86 IgV domain amino acid substitution mutant Q25I / F33L / H90I.

[0696] For example, the third or sixth domain comprises a CD86 variant polypeptide, the CD86 variant polypeptide comprising an extracellular domain amino acid substitution mutant of CD86, the extracellular domain amino acid substitution mutant of CD86 comprising one, two, three, four, five or more amino acid site mutations selected from the group consisting of: A13I, A13L, A13F, A13M, Q25A, Q25I, Q25V, Q25F, Q25M, F33A, F33L, F33V, F33M, M60R, I89A, I89L, I89V, I89F, I89M, H90I, H90V, H90M, H90F.

[0697] For example, the third or sixth domain comprises an extracellular domain amino acid substitution mutant of CD86, wherein the amino acid substitution mutant comprises the combination shown below: Q25I / F33L / H90I, Q25V / F33L / H90I, Q25I / F33V / H90I, Q25V / F33V / H90I, Q25I / F33L / H90V, Q25V / F33L / H90V, Q25 I / F33V / H90V, Q25V / F33V / H90V, A13L / Q25I / F33L / H90I, A13I / Q25I / F33L / H90I, A13L / Q25 V / F33L / H90I, A13I / Q25V / F33L / H90I, Q25I / F33L / I89L / H90I, Q25I / F33L / M60R / H90I, Q25V / F33L / I89L / H90I, Q25V / F33L / M60R / H90I, Q25F / F33L / H90I, Q25I / F33L / H90F, Q25I / F33A / H90I, Q25I / H90I, Q25I, H90I, Q25V / H90V, Q25V / H90I, Q25F / H90I, Q25F / H90V, A13F / Q25I / F33L / H90I, A13M / Q25I / F33L / H90I, Q25A / F33L / H90I, Q25M / F33L / H90I, Q25I / F33M / H90I, Q25I / F33L / I89V / H90I, Q25I / F33L / I89F / H90I, Q25I / F33L / I89M / H90I and Q25I / F33L / H90M.

[0698] For example, the third or sixth domain comprises an extracellular domain amino acid substitution mutant of CD86, the amino acid substitution mutant comprising the combination shown below: Q25I / F33L / H90I.

[0699] For example, the third or sixth domain contains an amino acid sequence as shown in SEQ ID NO: 97 to SEQ ID NO: 165.

[0700] For example, the third or sixth domain contains a CD80 variant polypeptide, and the mutant contains an amino acid substitution mutation of humanized CD80.

[0701] For example, the third or sixth domain comprises a CD80 variant peptide, which comprises an IgV domain amino acid substitution mutant of CD80 and / or an extracellular domain amino acid substitution mutant of humanized CD80.

[0702] For example, the CD80 mutant disclosed in PCT / CN2023 / 102271 is incorporated herein by reference.

[0703] The third structural domain and the sixth structural domain may have the same or different sequences and / or structures, and the sixth structural domain may or may not exist.

[0704] Fifth structural domain

[0705] For example, the fifth domain contains a peptide with CD3 binding domain masking function.

[0706] For example, the peptide with CD3 binding domain masking function of the fifth domain includes peptides selected from the following that have strong masking effects: QDGAEEMGGGSQDGAEEMGGI (SEQ ID No: 404), QDGNEAMGGGSQDGNEAMGGI (SEQ ID No: 406), QDGNEEAGGGSQDGNEEAGGI (SEQ ID No: 407), QDGNEEMGGGSQDGNEEMAGI (SEQ ID No: 408), QDGNEEMGGGSQDGNEEMGAI (SEQ ID No: 409), QDGNEEMGGGSQDGNEEMGGA (SEQ ID No: 410), QDGNEDMGGGSQDGNEDMGGI (SEQ ID No: 412), QDGNEDMGGGSQDGNEDMGSI (SEQ ID No: 414), QDGNDEMGGGSQDGNDEMGSI (SEQ ID No: 414). No: 415), QDGNEEMGSITQTPYQVSISGT (SEQ ID No: 424), QDGNEEMGSSIGGGSQDGNEEM (SEQ ID No: 425), QDGNEEMGGGSQDGNEEMGGITQTPY (SEQ ID No: 426), QDGNEEMGGGSQDGNEEMGSITQTPY (SEQ ID No: 427), QEGNEEMGSIGGGGSQEGNEEM (SEQ ID No: 428).

[0707] For example, the peptide with CD3 binding domain masking function in the fifth domain comprises peptides selected from the following that have moderate masking effect: QDANEEMGGGSQDANEEMGGI (SEQ ID No: 403), QDGNAEMGGGSQDGNAEMGGI (SEQ ID No: 405), QDGNEEMGGGSQDGNEEMGSI (SEQ ID No: 411), QDGNDEMGGGSQDGNDEMGGI (SEQ ID No: 413), QEGNEEMGGGSQEGNEEMGSI (SEQ ID No: 416), QEGNEEMGGGSQEGNEEMGGI (SEQ ID No: 417), QDGNEEMGGITQTPYKVSISGT (SEQ ID No: 418), QDGAAEMGGGSQDGAAEMGGI (SEQ ID No: 432), QDGNAAMGGGSQDGNAAMGGI (SEQ ID No: 413). No: 433), QDGNAEAGGGSQDGNAEAGGI (SEQ ID No: 434), QDGNAEMGGGSQDGNAEMAGI (SEQ ID No: 419), QDGNAEMGGGSQDGNAEMGAI (SEQ ID No: 420), QDGNAEMGGGSQDGNAEMGGA (SEQ ID No: 421), QDGNAEMLSGRSDAGQDGNAEMGGI (SEQ ID No: 433) No: 422), QDGAEEMGGGSGGGGSGGGGS (SEQ ID No: 423).

[0708] For example, the fifth domain having a CD3 binding domain masking peptide includes peptides selected from the following that have a weaker masking effect: ADGNEEMGGGSADGNEEMGGI (SEQ ID No: 401), QAGNEEMGGGSQAGNEEMGGI (SEQ ID No: 402), ADGNAEMGGGSADGNAEMGGI (SEQ ID No: 429), QAGNAEMGGGSQAGNAEMGGI (SEQ ID No: 430), QDANAEMGGGSQDANAEMGGI (SEQ ID No: 431).

[0709] Based on the AN_TCB_160 antibody, different masking peptides were introduced to construct the AN_PB series of antibodies for identification of masking function. The masking effect was evaluated by the strength of binding to human PBMCs or Jurkat cells. The masking effect of the CD3, HER2 bispecific antibody at 100 nM on the CD3 binding domain was calculated as follows: Masking effect = (1 - (MFI) AN_PB -MFI igG ) / (MFI AN_TCB_160 -MFI igG ))X 100%.

[0710] MFI AN_PB This refers to the MFI value of the corresponding AN_PB series antibody at 100 nM binding to PBMCs or Jurkat cells; MFI igG This refers to the MFI (Mean Free Fiber Index) value of human IgG binding to PBMCs or Jurkat cells at 100 nM; MFI AN_TCB_160 This refers to the MFI value of AN_TCB_160 binding to PBMCs or Jurkat cells. If the masking effect is ≥99%, it is considered strong masking; if 90% ≤ masking effect <99%, it is considered medium masking; and if the masking effect <90%, it is considered weak masking.

[0711] Enzyme digestion of linkers

[0712] For example, the fifth domain also contains an enzyme-liganded linker.

[0713] For example, the enzyme cleavage linker of the ground five domain contains a protease cleavage site fragment.

[0714] For example, the enzyme cleavage linker of the fifth domain contains one, two, three, four, five or more protease cleavage sites selected from the amino acid sequence of SEQ ID NO:3000-3036.

[0715] For example, the corresponding protease types of the fifth domain protease cleavage site fragment include, but are not limited to, matrix metalloproteinases (MMPs): PLGLWA (SEQ ID NO:3000), PLGLAGS (SEQ ID NO:3001), GPLGLWA (SEQ ID NO:3002), GPLGLWAQ (SEQ ID NO:3003), GVPDLGRFQTFE (SEQ ID NO:3004), GVPDVGHFSLFP (SEQ ID NO:3005), GVPDVGEFSLFP (SEQ ID NO:3006), GVPDVGNFSLFP (SEQ ID NO:3007), GVPDVGRFSLFP (SEQ ID NO:3008), GVPDVGHYSLFP (SEQ ID NO:3009), GVPDVGEYSLFP (SEQ ID NO:3010), GVPDVGNYSLFP (SEQ ID NO:3011), GVPDVGRYSLFP (SEQ ID NO:3011), GVPDVGRYSLFP (SEQ ID NO:3009). NO:3012); Urokinase (uPA): PRFKIIGG (SEQ ID NO:3013), PRFRIIGG (SEQ ID NO:3014); ST14 transmembrane serine protease (MTSP-1): LSGRSDNH (SEQ ID NO:0315), MTSP-1&uPA: LSGRSDAG (SEQ ID NO:0316); Transforming factor TGFβ: SSRHRRALD (SEQ ID NO:307); Plasminogen (PLG): RKSSIIIRMRDVVL (SEQ ID NO:3018); Staphylokinase (Sak): SSFFDKGKYKKGDDA (SEQ ID NO:3019); Human liver collagen: GPLGIAGI (SEQ ID NO:3020); Human α-2-macroglobulin (α2M): GPEGLRVG (SEQ ID NO:3012); NO:3021); Human PZPα-2-macroglobulin-like protein (PZP): YGAGLGVV (SEQ ID NO:3022), AGLLGVVER (SEQ ID NO:3023), AGLGISST (ESQ ID NO:3024).

[0716] For example, the protease cleavage site fragment of the fifth domain includes, or is not limited to, matrix metalloproteinases (MMPs) selected from the group consisting of: PLGLWA (SEQ ID NO:3000), PLGLAGS (SEQ ID NO:3001), GPLGLWA (SEQ ID NO:3002), GPLGLWAQ (SEQ ID NO:3003), GVPDLGRFQTFE (SEQ ID NO:3004), GVPDVGHFSLFP (SEQ ID NO:3005), GVPDVGEFSLFP (SEQ ID NO:3006), GVPDVGNFSLFP (SEQ ID NO:3007), GVPDVGRFSLFP (SEQ ID NO:3008), GVPDVGHYSLFP (SEQ ID NO:3009), GVPDVGEYSLFP (SEQ ID NO:3010), GVPDVGNYSLFP (SEQ ID NO:3011), GVPDVGRYSLFP (SEQ ID NO:3012), GVPDVGRYSLFP (SEQ ID NO:3013), GVPDVGRYSLFP (SEQ ID NO:3004), GVPDVGHFSLFP (SEQ ID NO:3005), GVPDVGEFSLFP (SEQ ID NO:3006), GVPDVGNFSLFP (SEQ ID NO:3007), GVPDVGRFSLFP (SEQ ID NO:3008), GVPDVGHYSLFP (SEQ ID NO:3009), GVPDVGEYSLFP (SEQ ID NO:3010), GVPDVGNYSLFP (SEQ ID NO:3011), GVPDVGRYSLFP (SEQ ID NO:3012), GVPDVGRYSLFP (SEQ ID NO:3003), GVPDVGRYSLFP (SEQ ID NO:3004), GVPDVGHFSLFP (SEQ ID NO:3005), GVPDVGEYSLFP (SEQ ID NO:3 NO:3012); Urokinase (uPA): PRFKIIGG (SEQ ID NO:3013), PRFRIIGG (SEQ ID NO:3014); ST14 transmembrane serine protease (MTSP-1): LSGRSDNH (SEQ ID NO:0315), MTSP-1&uPA: LSGRSDAG (SEQ ID NO:0316); Transforming factor TGFβ: SSRHRRALD (SEQ ID NO:307); Plasminogen (PLG): RKSSIIIRMRDVVL (SEQ ID NO:3018); Staphylokinase (Sak): SSFFDKGKYKKGDDA (SEQ ID NO:3019); Human liver collagen: GPLGIAGI (SEQ ID NO:3020); Human α-2-macroglobulin (α2M): GPEGLRVG (SEQ ID NO:3012); NO:3021); One, two, three, four, five or more of the following fragments: human PZPα-2-macroglobulin-like (PZP): YGAGLGVV (SEQ ID NO:3022), AGLGVVER (SEQ ID NO:3023), AGLGISST (SEQ ID NO:3024) to form a combination fragment.

[0717] For example, the protease cleavage site fragment of the fifth domain includes, but is not limited to, the following pre-combined cleavage site fragments: LSGRSDNHGSPLGLAGS (SEQ ID NO:3025), LSGRSDNHGGSPLGLAGS (SEQ ID NO:3026), PLGLAGSGGSLSGRSDNH (SEQ ID NO:3027), PLGLGSLSGRSDNH (SEQ ID NO:3028), LSGRSDNHSPAGLAGS (SEQ ID NO:3029), LSGRSDNHSPGALGAS (SEQ ID NO:3030), LSGRSDNHSPAGLGGS (SEQ ID NO:3031), LSGRSDNHSPAGLRGS (SEQ ID NO:3032), PAGLAGSGGSLSGRSDNH (SEQ ID NO:3033), PGALGSGGSLSGRSDNH (SEQ ID NO:3034), PAGLGGSGGSLSGRSDNH (SEQ ID NO:3035), PAGLRGSGGSLSGRSDNH (SEQ ID NO:3036), PAGLRGSGGSLSGRSDNH (SEQ ID NO:3027), PLGLGSLSGRSDNH (SEQ ID NO:3028), LSGRSDNHSPAGLAGS (SEQ ID NO:3029), LSGRSDNHSPGALGAS (SEQ ID NO:3030), LSGRSDNHSPAGLGGS (SEQ ID NO:3031), LSGRSDNHSPAGLRGS (SEQ ID NO:3032), PAGLAGSGGSLSGRSDNH (SEQ ID NO:3033), PGALGSGGSLSGRSDNH (SEQ ID NO:3034), PAGLGGSGGSLSGRSDNH (SEQ ID NO:3035), PAGLRGSGGSLSGRSDNH (SEQ ID NO:3035), PAGLRGSGGSLSGRSDNH (SEQ ID NO:3036), PAGLRGSGGSLSGRSDNH (SEQ ID NO:3037), PAGLAGSGGSLSGRSDNH (SEQ NO:3036)

[0718] For example, the protease cleavage site fragments of the fifth domain are linked by linkers, the amino acid sequences of which include, but are not limited to, GS, GGS, GSGS, GGGGS (SEQ ID NO: 5), GGGGSGGGGS (SEQ ID NO: 6), GGGGSGGGGSGGGGS (SEQ ID NO: 7), GGGGSGGGGSGGGGSGGGS (SEQ ID NO: 8), GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 9), and GGGGSGGGS (SEQ ID NO: 10). The linker amino acid sequence is located between two protease cleavage site fragments, between a masking peptide fragment and a protease cleavage site fragment, or between a protease cleavage site fragment and a first, second, or fourth domain.

[0719] For example, the masking peptide fragment of the fifth domain is directly or indirectly linked to the protease cleavage site fragment of the fifth domain.

[0720] For example, the C-terminus of the masking peptide fragment of the fifth domain is directly or indirectly linked to the N-terminus of the protease cleavage site fragment of the fifth domain.

[0721] For example, the C-terminus of the masking peptide fragment of the fifth domain is directly linked to the N-terminus of the protease cleavage site fragment of the fifth domain via a linker, and the amino acid sequence includes, but is not limited to, GS, GGS, GSGS, GGGGS (SEQ ID NO: 5), GGGGSGGGGS (SEQ ID NO: 6), GGGGSGGGGSGGGGS (SEQ ID NO: 7), GGGGSGGGGSGGGGSGGGS (SEQ ID NO: 8), GGGGSGGGGSGGGGSGGGSG (SEQ ID NO: 9), and GGGGSGGGS (SEQ ID NO: 10).

[0722] The fifth structural domain may or may not exist.

[0723] For example, the heavy chain of the first structural domain is directly connected to the heavy chain of the second structural domain.

[0724] For example, the heavy chain Fc segments of the first and second structural domains are connected by a knobs-into-holes structure.

[0725] For example, knots-into-holes pairing occurs by including one or more substitutions in the Fc segment of the heavy chain, which form heterodimeric pairings between the heavy chains. For example, CH3 in the first domain and CH3 in the second domain form a pestle-and-mortar substitution pair.

[0726] For example, the CH3 of the first domain and the CH3 of the second domain form a club-and-mortar substitution pair, such as T366 on one CH3 domain being replaced by a relatively large amino acid residue, such as tyrosine (Y) or tryptophan (W); L368 on another CH3 domain being replaced by a relatively small amino acid residue, such as alanine (A); and Y407 on another CH3 domain being replaced by a relatively small amino acid residue, such as threonine (T), alanine (A), or valine (V).

[0727] For example, the antigen-binding fragment of the first domain is directly or indirectly linked to the antigen-binding fragment of the second domain. For example, the indirect connection includes a connection via a linker.

[0728] For example, the linker comprises an amino acid sequence selected from the group shown below: SEQ ID NO: 5 to SEQ ID NO: 10.

[0729] For example, the first domain and the third domain are directly or indirectly connected.

[0730] For example, the first domain heavy chain is directly or indirectly connected to the third domain.

[0731] For example, the C-terminus of the first structural domain heavy chain is directly or indirectly connected to the N-terminus of the third structural domain.

[0732] For example, the N-terminus of the first structural domain heavy chain is directly or indirectly connected to the C-terminus of the third structural domain.

[0733] For example, the first domain light chain is directly or indirectly connected to the third domain.

[0734] For example, the C-terminus of the first structural domain light chain is directly or indirectly connected to the N-terminus of the third structural domain.

[0735] For example, the N-terminus of the first structural domain light chain is directly or indirectly connected to the C-terminus of the third structural domain.

[0736] For example, the first structural domain and the fourth structural domain are directly or indirectly connected.

[0737] For example, the first domain heavy chain is directly or indirectly connected to the fourth domain.

[0738] For example, the C-terminus of the first structural domain heavy chain is directly or indirectly connected to the N-terminus of the fourth structural domain.

[0739] For example, the N-terminus of the first structural domain heavy chain is directly or indirectly connected to the C-terminus of the fourth structural domain.

[0740] For example, the first domain light chain is directly or indirectly connected to the fourth domain.

[0741] For example, the C-terminus of the first structural domain light chain is directly or indirectly connected to the N-terminus of the fourth structural domain.

[0742] For example, the N-terminus of the first structural domain light chain is directly or indirectly connected to the C-terminus of the fourth structural domain.

[0743] For example, the first domain and the fifth domain are directly or indirectly connected.

[0744] For example, the first domain heavy chain is directly or indirectly connected to the fifth domain.

[0745] For example, the C-terminus of the first structural domain heavy chain is directly or indirectly connected to the N-terminus of the fifth structural domain.

[0746] For example, the N-terminus of the first structural domain heavy chain is directly or indirectly connected to the C-terminus of the fifth structural domain.

[0747] For example, the first domain light chain is directly or indirectly connected to the fifth domain.

[0748] For example, the C-terminus of the first structural domain light chain is directly or indirectly connected to the N-terminus of the fifth structural domain.

[0749] For example, th...

Claims

1. A fusion polypeptide comprising a first domain, a second domain and a third domain, the first domain being capable of binding CD3, the second domain being capable of binding tumor-associated antigen (TAA), and the third domain being capable of binding CD28 and / or CTLA4.

2. The fusion polypeptide of claim 1, wherein, The first domain contains an antibody or an antigen-binding fragment thereof.

3. The fusion polypeptide as described in any of the preceding claims, wherein, The antibody with the first domain is selected from the following group: recombinant antibody, single-domain antibody, heavy chain antibody, chimeric antibody and bispecific antibody.

4. The fusion polypeptide as described in any of the preceding claims, wherein, The first domain antigen-binding fragment is selected from one or more fragments from the group consisting of: Fab, Fab', Fv fragment, F(ab')2, F(ab)2, scFv, di-scFv, VHH and dAb.

5. The fusion polypeptide as described in any of the preceding claims, wherein, The first domain comprises an antibody, its antigen-binding fragment, or a variant thereof selected from the group consisting of: antibody OKT3, antibody UCHT1, antibody SP34, Blinatumamab, Tebentafusp, Mosunetuzumab, and Teclistamab.

6. The fusion polypeptide as described in any of the preceding claims, wherein, The first domain contains the antibody SP34 mutant or its antigen-binding site.

7. The fusion polypeptide of claim 6, wherein, The first domain may contain an antibody SP34 mutant or its antigen-binding site, wherein the mutation occurs in the CDR region.

8. The fusion polypeptide of claim 7, wherein, The mutation occurs in the HCDR region and includes one or more amino acid site mutations selected from the group shown in SEQ ID NO:22 of the antibody SP34 heavy chain variable region: T31D, R50K, N100D, N97S, F100fH, S100aA, V100cT.

9. The fusion polypeptide of claim 7, wherein, The mutation occurs in the LCDR region and comprises one or more amino acid site mutations selected from the group shown in SEQ ID NO:12 of antibody SP34 light chain variable region: N94Q.

10. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain contains a single-chain immunoglobulin domain.

11. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain contains a single-chain immunoglobulin IgG antibody.

12. The fusion polypeptide of claim 11, wherein, The single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

13. The fusion polypeptide as described in any of the preceding claims, wherein, The first domain contains a single-chain immunoglobulin Fc domain.

14. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain contains the Fc domain of a single-chain immunoglobulin IgG antibody.

15. The fusion polypeptide of claim 14, wherein, The Fc domain of the single-chain immunoglobulin IgG antibody includes human IgG1 Fc domain, human IgG2 Fc domain, human IgG3 Fc domain, human IgG4 Fc domain, mouse IgG1 Fc domain, mouse IgG2a Fc domain, mouse IgG2b Fc domain, or mouse IgG3 Fc domain.

16. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences, wherein the first domain CH2 is located between the variable region and the CH3 domain; preferably, the Fc fragment contains any amino acid sequence selected from the group consisting of: SEQ ID NO: 3, SEQ ID NO:

4.

17. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain comprises a heavy chain variable region, wherein the HCDR1, HCDR2, and / or HCDR3 amino acid sequences or variant sequences thereof of the heavy chain variable region are selected from any one of the following amino acid sequences: SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 302, SEQ ID NO: 303, SEQ ID NO: 304, SEQ ID NO: 307, SEQ ID NO: 308, SEQ ID NO: 309, SEQ ID NO: 312, SEQ ID NO: 313, SEQ ID NO: 314, SEQ ID NO: 317, SEQ ID NO: 318, SEQ ID NO: 319, SEQ ID NO: 327, SEQ ID NO: 328, SEQ ID NO: 319 ... SEQ ID NO: 329, SEQ ID NO: 337, SEQ ID NO: 338, SEQ ID NO: 339; wherein, the first structural domain optionally further includes a light chain variable region, wherein the LCDR1, LCDR2 and / or LCDR3 amino acid sequences or variant sequences thereof of the light chain variable region of the first structural domain contain any one of the following amino acid sequences: SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 323, SEQ ID NO: 324, SEQ ID NO: 325, SEQ ID NO: 333, SEQ ID NO: 334, SEQ ID NO:

335.

18. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain comprises a heavy chain variable region VH of the antibody heavy chain, the VH comprising any amino acid sequence selected from the group consisting of: SEQ ID NO: 22, SEQ ID NO: 27, SEQ ID NO: 32, SEQ ID NO: 42, SEQ ID NO: 301, SEQ ID NO: 306, SEQ ID NO: 311, SEQ ID NO: 316, SEQ ID NO: 326, SEQ ID NO:

336.

19. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain comprises an antibody heavy chain, which comprises an amino acid sequence selected from any of the following groups: SEQ ID NO: 21, SEQ ID NO: 26, SEQ ID NO: 31, SEQ ID NO: 36, SEQ ID NO: 300, SEQ ID NO: 305, SEQ ID NO: 310, SEQ ID NO: 315, SEQ ID NO: 320, SEQ ID NO:

330.

20. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain comprises a light chain variable region VL of the antibody light chain, the VL comprising any amino acid sequence selected from the group shown below: SEQ ID NO: 12, SEQ ID NO: 17, SEQ ID NO: 38, SEQ ID NO: 322, SEQ ID NO:

332.

21. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain comprises an antibody light chain, the antibody light chain comprising any one of the amino acid sequences selected from the group shown below: SEQ ID NO: 11, SEQ ID NO:

16.

22. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain may contain HCDR1, HCDR2, and HCDR3 of the antibody heavy chain, wherein: The HCDR1, HCDR2, and HCDR3 may respectively contain the amino acid sequences shown in SEQ ID NO: 23, SEQ ID NO: 24, and SEQ ID NO: 25; or may respectively contain the amino acid sequences shown in SEQ ID NO: 28, SEQ ID NO: 29, and SEQ ID NO: 30; or may respectively contain the amino acid sequences shown in SEQ ID NO: 33, SEQ ID NO: 34, and SEQ ID NO: 35; or may respectively contain the amino acid sequences shown in SEQ ID NO: 43, SEQ ID NO: 44, and SEQ ID NO: 45; or may respectively contain the amino acid sequences shown in SEQ ID NO: 302, SEQ ID NO: 303, and SEQ ID NO: 304; or may respectively contain the amino acid sequences shown in SEQ ID NO: 307, SEQ ID NO: 308, and SEQ ID NO: 309; or may respectively contain the amino acid sequences shown in SEQ ID NO: 312, SEQ ID NO: 313, and SEQ ID NO: 314; or may respectively contain the amino acid sequences shown in SEQ ID NO: 317, SEQ ID NO: 318, and SEQ ID NO: 31 ...9; or may respectively contain the amino acid sequences shown in SEQ ID NO: 312, SEQ ID NO: 313, and SEQ ID NO: 319; or may respectively contain the amino acid sequences shown in SEQ ID NO: The amino acid sequence shown in NO: 319 may be included; or may contain the amino acid sequences shown in SEQ ID NO: 327, SEQ ID NO: 328, SEQ ID NO: 329 respectively; or may contain the amino acid sequences shown in SEQ ID NO: 337, SEQ ID NO: 338, SEQ ID NO: 339 respectively.

23. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain may comprise LCDR1, LCDR2, and LCDR3 of the antibody light chain, wherein: The LCDR1, LCDR2, and LCDR3 may each contain the amino acid sequences shown in SEQ ID NO: 13, SEQ ID NO: 14, and SEQ ID NO: 15; or may each contain the amino acid sequences shown in SEQ ID NO: 18, SEQ ID NO: 19, and SEQ ID NO: 20; or may each contain the amino acid sequences shown in SEQ ID NO: 39, SEQ ID NO: 40, and SEQ ID NO: 41; or may each contain the amino acid sequences shown in SEQ ID NO: 323, SEQ ID NO: 324, and SEQ ID NO: 325; or may each contain the amino acid sequences shown in SEQ ID NO: 333, SEQ ID NO: 334, and SEQ ID NO:

335. Fusion polypeptide.

24. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain does not contain light chains.

25. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first domain does not contain the CH1 domain.

26. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain can bind to tumor-associated antigens (TAAs).

27. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain can bind to proteins or tumor-associated antigens that are overexpressed on tumor cells relative to the corresponding non-tumor cells.

28. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain contains an antibody or an antigen-binding fragment thereof.

29. The fusion polypeptide as claimed in any of the preceding claims, wherein, The antibody with the second domain is selected from the following group: recombinant antibody, single-domain antibody, heavy chain antibody, chimeric antibody and bispecific antibody.

30. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain antigen-binding fragment is selected from one or more fragments from the group consisting of: Fab, Fab', Fv fragment, F(ab')2, F(ab)2, scFv, di-scFv, VHH and dAb.

31. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain can bind to one or more of the targets shown in the following group: PD-L1, PD-L2, VEGF, VEGFR, FGFR, HER2, HGFR, PIP-LAR, CD44, CD147, TfR, CDCP1, α6β4, α6β3, Trop2, HHLA2, GCC, 5T4, EpCAM, GPRC5D, BCMA, CD19, CD20, HER-2neu, DLL1, DLL3, B7H3, HER-3, HER-4, EGFR, PSMA, CEA, MUC-1 (mucin), MUC2, MUC3, MUC4, MUC5AC, MUC5B, MUC7, CD123, CD33, CD30, CD38, PTK7, EphA2, NKG2A, Nkp36, Tim3, CD20, Her2.

32. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain includes a single-chain immunoglobulin domain.

33. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain contains a single-chain immunoglobulin IgG antibody.

34. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

35. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain contains a single-chain immunoglobulin Fc domain.

36. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain contains the Fc domain of a single-chain immunoglobulin IgG antibody.

37. The fusion polypeptide as claimed in any of the preceding claims, wherein, The Fc domain of the single-chain immunoglobulin IgG antibody includes human IgG1 Fc domain, human IgG2 Fc domain, human IgG3 Fc domain, human IgG4 Fc domain, mouse IgG1 Fc domain, mouse IgG2a Fc domain, mouse IgG2b Fc domain, or mouse IgG3 Fc domain.

38. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences, with the CH2 domain located between the variable region and the CH3 domain; preferably, the Fc fragment contains any amino acid sequence selected from the group shown below: SEQ ID NO: 3, SEQ ID NO:

4.

39. The fusion polypeptide as claimed in any of the preceding claims, wherein, The HCDR1, HCDR2, and / or HCDR3 amino acid sequences or variant sequences thereof in the heavy chain variable region, comprising any amino acid sequence selected from the group shown below: SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 64, SEQ ID NO: 65, SEQ ID NO: 66, SEQ ID NO: 69, SEQ ID NO: 70, SEQ ID NO: 71, SEQ ID NO: 74, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 79, SEQ ID NO: 80, SEQ ID NO: 81, SEQ ID NO: 84, SEQ ID NO: 85, SEQ ID NO: 86, SEQ ID NO: 94, SEQ ID NO: 95, SEQ ID NO: 96, SEQ ID NO: 1002, SEQ ID NO: 1003, SEQ ID NO: 1004, SEQ ID NO: 1011, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 64, SEQ ID NO: 65, SEQ ID NO: 86, SEQ ID NO: 1002, SEQ ID NO: 1003, SEQ ID NO: 1004, SEQ ID NO: 1011, SEQ ID NO: 49, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 64, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 1002 SEQ ID NO: 1012, SEQ ID NO: 1013, SEQ ID NO: 2007, SEQ ID NO: 2008, SEQ ID NO: 2009, SEQ ID NO: 2012, SEQ ID NO: 2013, SEQ ID NO: 2014; the light chain variable region's LCDR1, LCDR2 and / or LCDR3 amino acid sequences or variant sequences thereof, comprising any amino acid sequence selected from the following group: SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 89, SEQ ID NO: 90, SEQ ID NO: 91, SEQ ID NO: 1015, SEQ ID NO: 1016, SEQ ID NO: 1017, SEQ ID NO: 2003, SEQ ID NO: 2004, SEQ ID NO: 2005.

40. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structure includes a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain variable region VH comprising any amino acid sequence selected from the group shown below: SEQ ID NO: 47, SEQ ID NO: 58, SEQ ID NO: 63, SEQ ID NO: 68, SEQ ID NO: 73, SEQ ID NO: 78, SEQ ID NO: 83, SEQ ID NO: 93, SEQ ID NO: 1001, SEQ ID NO: 1010, SEQ ID NO: 2006, SEQ ID NO: 2011.

41. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structure comprises an antibody heavy chain, the antibody heavy chain comprising any amino acid sequence selected from the group consisting of: SEQ ID NO: 46, SEQ ID NO: 57, SEQ ID NO: 62, SEQ ID NO: 67, SEQ ID NO: 72, SEQ ID NO: 77, SEQ ID NO: 82, SEQ ID NO: 92, SEQ ID NO: 1000, SEQ ID NO: 1005, SEQ ID NO: 1018, SEQ ID NO: 2000, SEQ ID NO: 2010.

42. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structure includes a light chain variable region VL of an antibody light chain, the antibody light chain comprising any amino acid sequence selected from the group shown below: SEQ ID NO: 53, SEQ ID NO: 88, SEQ ID NO: 1014, SEQ ID NO: 2002.

43. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain comprises an antibody light chain, the antibody light chain comprising any one of the amino acid sequences selected from the group shown below: SEQ ID NO: 52, SEQ ID NO:

87.

44. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may include HCDR1, HCDR2, and HCDR3 of the antibody heavy chain and LCDR1, LCDR2, and LCDR3 of the antibody light chain, wherein HCDR1, HCDR2, and HCDR3 may each contain amino acid sequences as shown in SEQ ID NO: 59, SEQ ID NO: 60, and SEQ ID NO: 61, and LCDR1, LCDR2, and LCDR3 may each contain amino acid sequences as shown in SEQ ID NO: 54, SEQ ID NO: 55, and SEQ ID NO: 56, respectively.

45. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may include a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain VH may include an amino acid sequence as shown in SEQ ID NO: 58, and the second domain may include a light chain variable region VL of the antibody light chain, the antibody light chain VL may include an amino acid sequence as shown in SEQ ID NO:

53.

46. ​​The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain an antibody heavy chain and / or an antibody light chain, wherein the antibody heavy chain may contain an amino acid sequence as shown in SEQ ID NO: 57, and the antibody light chain may contain an amino acid sequence as shown in SEQ ID NO:

52.

47. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 48, SEQ ID NO: 49, and SEQ ID NO: 50, respectively.

48. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO:

47.

49. The fusion polypeptide according to any of the preceding claims, wherein, The second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO:

46.

50. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 64, SEQ ID NO: 65, and SEQ ID NO: 66, respectively.

51. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO:

63.

52. The fusion polypeptide according to any of the preceding claims, wherein, The second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO:

62.

53. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 69, SEQ ID NO: 70, and SEQ ID NO: 71, respectively.

54. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may include the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO:

68.

55. The fusion polypeptide according to any of the preceding claims, wherein, The second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO:

67.

56. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may contain amino acid sequences as shown in SEQ ID NO: 74, SEQ ID NO: 75, and SEQ ID NO: 76, respectively.

57. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO:

73.

58. The fusion polypeptide according to any of the preceding claims, wherein, The second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO:

72.

59. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may contain amino acid sequences as shown in SEQ ID NO: 79, SEQ ID NO: 80, and SEQ ID NO: 81, respectively.

60. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO:

78.

61. The fusion polypeptide according to any of the preceding claims, wherein, The second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO:

77.

62. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may contain amino acid sequences as shown in SEQ ID NO: 84, SEQ ID NO: 85, and SEQ ID NO: 86, respectively.

63. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO:

83.

64. The fusion polypeptide according to any of the preceding claims, wherein, The second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO:

82.

65. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may include HCDR1, HCDR2, and HCDR3 of the antibody heavy chain and LCDR1, LCDR2, and LCDR3 of the antibody light chain, wherein HCDR1, HCDR2, and HCDR3 may each contain amino acid sequences as shown in SEQ ID NO: 94, SEQ ID NO: 95, and SEQ ID NO: 96, and LCDR1, LCDR2, and LCDR3 may each contain amino acid sequences as shown in SEQ ID NO: 89, SEQ ID NO: 90, and SEQ ID NO: 91, respectively.

66. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may include a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain VH may include an amino acid sequence as shown in SEQ ID NO: 93, and the second domain may include a light chain variable region VL of the antibody light chain, the antibody light chain VL may include an amino acid sequence as shown in SEQ ID NO:

88.

67. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain an antibody heavy chain and / or an antibody light chain, wherein the antibody heavy chain may contain an amino acid sequence as shown in SEQ ID NO: 92, and the antibody light chain may contain an amino acid sequence as shown in SEQ ID NO:

87.

68. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 1002, SEQ ID NO: 1003, and SEQ ID NO: 1004, respectively.

69. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO: 1001.

70. The fusion polypeptide according to any of the preceding claims, wherein, The second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 1000 or SEQ ID NO: 1005.

71. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may comprise the heavy chains HCDR1, HCDR2, and HCDR3 and the light chains LCDR1, LCDR2, and LCDR3 of the scFv antibody, wherein HCDR1, HCDR2, and HCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 1011, SEQ ID NO: 1012, and SEQ ID NO: 1013, respectively, and LDR1, LCDR2, and LCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 1015, SEQ ID NO: 1016, and SEQ ID NO: 1017, respectively.

72. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may include the heavy chain variable region VH and the light chain variable region VL of the scFv antibody. The VH may contain the amino acid sequence shown in SEQ ID NO: 1010, and the VL may contain the amino acid sequence shown in SEQ ID NO: 1014.

73. The fusion polypeptide according to any of the preceding claims, wherein, The second domain may contain an scFv antibody, which may contain an amino acid sequence as shown in SEQ ID NO: 1009 or SEQ ID NO: 1018.

74. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may comprise the heavy chains HCDR1, HCDR2, and HCDR3 and the light chains LCDR1, LCDR2, and LCDR3 of the scFv antibody, wherein HCDR1, HCDR2, and HCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 2007, SEQ ID NO: 2008, and SEQ ID NO: 2009, respectively, and LDR1, LCDR2, and LCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 2003, SEQ ID NO: 2004, and SEQ ID NO: 2005, respectively.

75. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may include the heavy chain variable region VH and the light chain variable region VL of the scFv antibody. The VH may contain the amino acid sequence shown in SEQ ID NO: 2006, and the VL may contain the amino acid sequence shown in SEQ ID NO: 2002.

76. The fusion polypeptide according to any of the preceding claims, wherein, The second domain may contain an scFv antibody, which may contain an amino acid sequence as shown in SEQ ID NO: 2001 or SEQ ID NO: 2000.

77. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain CDR1, CDR2 and CDR3 of a single-domain antibody, wherein CDR1, CDR2 and CDR3 may contain amino acid sequences as shown in SEQ ID NO: 2012, SEQ ID NO: 2013 and SEQ ID NO: 2014, respectively.

78. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain may contain the heavy chain variable region VHH of a single-domain antibody, wherein the VHH may contain an amino acid sequence as shown in SEQ ID NO: 2011.

79. The fusion polypeptide according to any of the preceding claims, wherein, The second domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 2010.

80. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structural domain does not contain light chains.

81. The fusion polypeptide as claimed in any of the preceding claims, wherein, The aforementioned second-domain fusion peptide does not contain a CH1 domain.

82. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain can combine CD28 and / or CTLA4.

83. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain contains CD86 or CD80 or their functionally active fragments, or variants thereof.

84. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain is selected from the following group: CD86 or CD80 derived from humans or mice, or their functionally active fragments or variants thereof.

85. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain contains the extracellular domain of CD86 or CD80, or a functionally active fragment thereof, or a variant thereof.

86. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain contains the IgV of CD86 or CD80, or a functionally active fragment thereof, or a variant thereof.

87. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain contains a CD86 variant polypeptide, which contains an amino acid substitution mutation of human CD86.

88. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain comprises a CD86 variant polypeptide, which comprises an IgV domain amino acid substitution mutant of CD86 and / or an extracellular domain amino acid substitution mutant of human CD86.

89. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain comprises a CD86 variant polypeptide, which comprises an IgV domain amino acid substitution mutant of CD86, wherein the mutation site of the IgV domain amino acid substitution mutant of CD86 comprises one, two, three, four, five or more amino acid site mutations selected from the group consisting of: A13I, A13L, A13F, A13M, Q25A, Q25I, Q25V, Q25F, Q25M, F33A, F33L, F33V, F33M, M60R, I89A, I89L, I89V, I89F, I89M, H90I, H90V, H90M, H90F.

90. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain comprises a CD86 variant polypeptide, which contains an IgV domain amino acid substitution mutant of CD86, wherein the amino acid substitution mutant comprises the combination shown below: Q25I / F33L / H90I, Q25V / F33L / H90I, Q25I / F33V / H90I, Q25V / F33V / H90I, Q25I / F33L / H90V, Q25V / F33L / H90V, Q25I / F33V / H90V, Q25V / F33V / H90V, A13L / Q25I / F33L / H90I, A13I / Q25I / F33L / H90I, A 13L / Q25V / F33L / H90I, A13I / Q25V / F33L / H90I, Q25I / F33L / I89L / H90I, Q25I / F33L / M60R / H90 I. Q25V / F33L / I89L / H90I, Q25V / F33L / M60R / H90I, Q25F / F33L / H90I, Q25I / F33L / H90F, Q25I / F33A / H90I, Q25I / H90I, Q25I, H90I, Q25V / H90V, Q25V / H90I, Q25F / H90I, Q25F / H90V, A13F / Q 25I / F33L / H90I, A13M / Q25I / F33L / H90I, Q25A / F33L / H90I, Q25M / F33L / H90I, Q25I / F33M / H90I, Q25I / F33L / I89V / H90I, Q25I / F33L / I89F / H90I, Q25I / F33L / I89M / H90I and Q25I / F33L / H90M.

91. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain comprises a CD86 variant polypeptide, which contains the CD86 IgV domain amino acid substitution mutant Q25I / F33L / H90I.

92. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain comprises a CD86 variant polypeptide, which comprises an extracellular domain amino acid substitution mutant of CD86, wherein the extracellular domain amino acid substitution mutant of CD86 comprises one, two, three, four, five or more amino acid site mutations selected from the group consisting of: A13I, A13L, A13F, A13M, Q25A, Q25I, Q25V, Q25F, Q25M, F33A, F33L, F33V, F33M, M60R, I89A, I89L, I89V, I89F, I89M, H90I, H90V, H90M, H90F.

93. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain comprises an extracellular domain amino acid substitution mutant of CD86, wherein the amino acid substitution mutant comprises the following combinations: Q25I / F33L / H90I, 25V / F33L / H90I, Q25I / F33V / H90I, Q25V / F33V / H90I, Q25I / F33L / H90V, Q25V / F33L / H90V, Q25I / F33V / H 90V, Q25V / F33V / H90V, A13L / Q25I / F33L / H90I, A13I / Q25I / F33L / H90I, A13L / Q25V / F33L / H90I, A13I / Q25V / F33L / H90I, Q25I / F33L / I89L / H90I, Q25I / F33L / M60R / H90I, Q25V / F33L / I89L / H90I, Q25V / F33L / M60R / H90I, Q25F / F33L / H90I, Q25I / F33L / H90F, Q25I / F33A / H90 I, Q25I / H90I, Q25I, H90I, Q25V / H90V, Q25V / H90I, Q25F / H90I, Q25F / H90V, A13F / Q25I / F3 3L / H90I, A13M / Q25I / F33L / H90I, Q25A / F33L / H90I, Q25M / F33L / H90I, Q25I / F33M / H90I, Q 25I / F33L / I89V / H90I, Q25I / F33L / I89F / H90I, Q25I / F33L / I89M / H90I and Q25I / F33L / H90M.

94. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain comprises an extracellular domain amino acid substitution mutant of CD86, the amino acid substitution mutant comprising the combination shown below: Q25I / F33L / H90I.

95. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain comprises an amino acid sequence selected from SEQ ID NO: 97 to SEQ ID NO:

165.

96. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain contains a CD80 variant polypeptide, and the mutant contains an amino acid substitution mutation of human CD80.

97. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third domain comprises a CD80 variant polypeptide, which comprises an IgV domain amino acid substitution mutant of CD80 and / or an extracellular domain amino acid substitution mutant of human CD80.

98. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain is directly or indirectly connected to the second structural domain.

99. The fusion polypeptide as claimed in any of the preceding claims, wherein, The heavy chain Fc of the first structural domain is directly or indirectly connected to the heavy chain Fc of the second structural domain.

100. The fusion polypeptide of claim 99, wherein, The heavy chain Fc segment of the first structural domain is connected to the heavy chain Fc of the second structural domain via disulfide bonds.

101. The fusion polypeptide of claim 99, wherein, The heavy chain of the first structural domain forms a heterodimer with the heavy chain of the second structural domain.

102. The fusion polypeptide of claim 101, wherein, The heavy chain Fc segments of the first structural domain and the heavy chain Fc segments of the second structural domain are paired and connected through a pestle-mortar structure.

103. The fusion polypeptide of claim 102, wherein, Knob-into-hole pairing involves one or more substitutions in the Fc segment of the heavy chain, which form a heterodimer pairing between the two heavy chains.

104. The fusion polypeptide according to any one of claims 102-103, wherein, CH3 in the first domain and CH3 in the second domain form a pestle-mortar structure substitution pair.

105. The fusion polypeptide of claim 104, wherein, The T366 and / or Y407 amino acid residues in one of the CH3 domains of the first and second domains are replaced, and the L368 amino acid residue in the other CH3 domain is replaced.

106. The fusion polypeptide of claim 105, wherein, T366 is replaced by tyrosine (Y) or tryptophan (W); and / or Y407 is replaced by threonine (T), alanine (A) or valine (V); and / or L368 is replaced by alanine (A).

107. The fusion polypeptide according to any one of claims 1-98, wherein, The antigen-binding fragment of the first domain is directly or indirectly linked to the second domain.

108. The fusion polypeptide of claim 107, wherein, The N-terminus of the antigen-binding fragment of the first domain is directly or indirectly connected to the C-terminus of the second domain; or the C-terminus of the antigen-binding fragment of the first domain is directly or indirectly connected to the N-terminus of the second domain.

109. The fusion polypeptide according to any one of claims 107-108, wherein, The heavy chain of the antigen-binding fragment of the first domain is directly or indirectly connected to the heavy chain of the second domain; or the light chain of the antigen-binding fragment of the first domain is directly or indirectly connected to the heavy chain of the second domain; or the heavy chain of the antigen-binding fragment of the first domain is directly or indirectly connected to the light chain of the second domain; or the light chain of the antigen-binding fragment of the first domain is directly or indirectly connected to the light chain of the second domain.

110. The fusion polypeptide according to any one of claims 107-109, wherein, The C-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the second domain; or the C-terminus of the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the second domain; or the C-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the second domain; or the N-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the second domain; or the N-terminus of the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the second domain; or the N-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the second domain; or the N-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the second domain; or the N-terminus of the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the second domain.

111. The fusion polypeptide according to any one of claims 1-98, wherein, The first domain is directly or indirectly linked to the antigen-binding fragment of the second domain.

112. The fusion polypeptide of claim 111, wherein, The N-terminus of the first domain is directly or indirectly connected to the C-terminus of the antigen-binding fragment of the second domain; or the C-terminus of the first domain is directly or indirectly connected to the N-terminus of the antigen-binding fragment of the second domain.

113. The fusion polypeptide according to any one of claims 111-112, wherein, The heavy chain of the first domain is directly or indirectly connected to the heavy chain of the antigen-binding fragment of the second domain; or the light chain of the first domain is directly or indirectly connected to the heavy chain of the antigen-binding fragment of the second domain; or the heavy chain of the first domain is directly or indirectly connected to the light chain of the antigen-binding fragment of the second domain; or the light chain of the first domain is directly or indirectly connected to the light chain of the antigen-binding fragment of the second domain.

114. The fusion polypeptide according to any one of claims 111-113, wherein, The C-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the first domain; or the C-terminus of the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the first domain; or the C-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the first domain; or the N-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the first domain; or the N-terminus of the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the first domain; or the N-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the first domain; or the N-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the first domain; or the N-terminus of the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the first domain.

115. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first and third structural domains are directly or indirectly connected.

116. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain heavy chain is directly or indirectly connected to the third structural domain. For example, the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, or the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the third structural domain.

117. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain light chain is directly or indirectly connected to the third structural domain. For example, the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the third structural domain, or the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the third structural domain.

118. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second and third structural domains are directly or indirectly connected.

119. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structural domain heavy chain is directly or indirectly connected to the third structural domain. For example, the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, or the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the third structural domain.

120. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structural domain light chain is directly or indirectly connected to the third structural domain. For example, the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the third structural domain, or the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the third structural domain.

121. The fusion polypeptide according to any one of claims 99-106 or 115-120, wherein, The N-terminus of the first structural domain is directly or indirectly connected to the C-terminus of the third structural domain, and the second structural domain is not directly or indirectly connected to the third structural domain; or the C-terminus of the first structural domain is directly or indirectly connected to the N-terminus of the third structural domain, and the second structural domain is not directly or indirectly connected to the third structural domain; or the N-terminus of the second structural domain is directly or indirectly connected to the C-terminus of the third structural domain, and the first structural domain is not directly or indirectly connected to the third structural domain; or the C-terminus of the second structural domain is directly or indirectly connected to the N-terminus of the third structural domain, and the first structural domain is not directly or indirectly connected to the third structural domain.

122. The fusion polypeptide according to any one of claims 107-114 or 115-120, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain.

123. The fusion polypeptide of claim 122, wherein, The heavy chain of the first structural domain is directly or indirectly connected to the heavy chain of the second structural domain; and the first structural domain is directly or indirectly connected to the third structural domain.

124. The fusion polypeptide of claim 123, wherein, The C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain.

125. The fusion polypeptide of claim 124, wherein, The C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain.

126. The fusion polypeptide of claim 123, wherein, The N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the first structure is directly or indirectly connected to the third structural domain.

127. The fusion polypeptide of claim 126, wherein, The N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain.

128. The fusion polypeptide of claim 122, wherein, The heavy chain of the first structural domain is directly or indirectly connected to the light chain of the second structural domain; and the first structural domain is directly or indirectly connected to the third structural domain.

129. The fusion polypeptide of claim 128, wherein, The C-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the N-terminus of the light chain of the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain.

130. The fusion polypeptide of claim 129, wherein, The C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain.

131. The fusion polypeptide as claimed in claim 128, wherein, The N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the first structure is directly or indirectly connected to the third structural domain.

132. The fusion polypeptide of claim 131, wherein, The N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain.

133. The fusion polypeptide of claim 122, wherein, The light chain of the first structural domain is directly or indirectly connected to the heavy chain of the second structural domain; and the first structural domain is directly or indirectly connected to the third structural domain.

134. The fusion polypeptide of claim 133, wherein, The C-terminus of the light chain of the first structural domain is directly or indirectly connected to the N-terminus of the heavy chain of the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain.

135. The fusion polypeptide of claim 134, wherein, The C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain.

136. The fusion polypeptide of claim 133, wherein, The N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the heavy chain of the second structural domain, and the first structure is directly or indirectly connected to the third structural domain.

137. The fusion polypeptide of claim 136, wherein, The N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain.

138. The fusion polypeptide of claim 122, wherein, The light chain of the first structural domain is directly or indirectly connected to the light chain of the second structural domain; and the first structural domain is directly or indirectly connected to the third structural domain.

139. The fusion polypeptide of claim 138, wherein, The C-terminus of the light chain of the first structural domain is directly or indirectly connected to the N-terminus of the light chain of the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain.

140. The fusion polypeptide of claim 139, wherein, The C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain.

141. The fusion polypeptide of claim 138, wherein, The N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the light chain of the second structural domain, and the first structure is directly or indirectly connected to the third structural domain.

142. The fusion polypeptide of claim 141, wherein, The N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain; or the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the third structural domain.

143. The fusion polypeptide according to any one of claims 107-114 or 115-120, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

144. The fusion polypeptide of claim 143, wherein, The heavy chain of the first structural domain is directly or indirectly connected to the heavy chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

145. The fusion polypeptide of claim 144, wherein, The N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

146. The fusion polypeptide of claim 145, wherein, The N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the N-end of the heavy chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain.

147. The fusion polypeptide of claim 144, wherein, The C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

148. The fusion polypeptide of claim 147, wherein, The C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain.

149. The fusion polypeptide of claim 143, wherein, The heavy chain of the first structural domain is directly or indirectly connected to the light chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

150. The fusion polypeptide of claim 149, wherein, The N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

151. The fusion polypeptide of claim 150, wherein, The N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the N-end of the heavy chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the heavy chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain.

152. The fusion polypeptide of claim 149, wherein, The C-terminus of the heavy chain of the first structural domain is directly or indirectly connected to the N-terminus of the light chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

153. The fusion polypeptide of claim 152, wherein, The C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the N-end of the heavy chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain.

154. The fusion polypeptide of claim 143, wherein, The light chain of the first structural domain is directly or indirectly connected to the heavy chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

155. The fusion polypeptide of claim 154, wherein, The N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the heavy chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

156. The fusion polypeptide of claim 155, wherein, The N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the N-end of the heavy chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the heavy chain of the second structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain.

157. The fusion polypeptide of claim 154, wherein, The C-terminus of the light chain of the first structural domain is directly or indirectly connected to the N-terminus of the heavy chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

158. The fusion polypeptide of claim 157, wherein, The C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the heavy chain of the second structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain.

159. The fusion polypeptide of claim 143, wherein, The light chain of the first structural domain is directly or indirectly connected to the light chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

160. The fusion polypeptide of claim 159, wherein, The N-terminus of the light chain of the first structural domain is directly or indirectly connected to the C-terminus of the light chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

161. The fusion polypeptide of claim 160, wherein, The N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain; or the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the light chain of the second structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain.

162. The fusion polypeptide of claim 159, wherein, The C-terminus of the light chain of the first structural domain is directly or indirectly connected to the N-terminus of the light chain of the second structural domain, and the second structural domain is directly or indirectly connected to the third structural domain.

163. The fusion polypeptide of claim 162, wherein, The C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the third structural domain; or the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the light chain of the second structural domain, and the N-end of the heavy chain of the second structural domain is directly or indirectly connected to the C-end of the third structural domain.

164. The fusion polypeptide of any of the preceding claims further comprises a fourth domain, which is capable of binding a tumor-associated antigen (TAA), or the fourth domain may be absent.

165. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain can bind to proteins or tumor-associated antigens that are overexpressed on tumor cells relative to the corresponding non-tumor cells.

166. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain contains an antibody or an antigen-binding fragment thereof.

167. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain antibody is selected from the following group: recombinant antibodies, single-domain antibodies, heavy chain antibodies, chimeric antibodies, and bispecific antibodies.

168. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain antigen-binding fragment is selected from one or more fragments from the group consisting of: Fab, Fab', Fv fragment, F(ab')2, F(ab)2, scFv, di-scFv, VHH, and dAb.

169. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain can bind to one or more of the following targets: PD-L1, PD-L2, VEGF, VEGFR, FGFR, HER2, HGFR, PIP-LAR, CD44, CD147, TfR, CDCP1, α6β4, α6β3, Trop2, HHLA2, GCC, 5T4, EpCAM, GPRC5D, BCMA, CD19, CD20, HER-2neu, DLL1, DLL3, B7H3. HER-3, HER-4, EGFR, PSMA, CEA, MUC-1 (mucin), MUC2, MUC3, MUC4, MUC5AC, MUC5B, MUC7, CD123, CD33, CD30, CD38, PTK7, EphA2, NKG2A, Nkp36, Tim3, CD20, Her2, HHLA2, PD-L1, GCC, EGFR, DLL3 and / or B7H3, 5T4 and / or CEA.

170. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain includes a single-chain immunoglobulin domain.

171. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain contains a single-chain immunoglobulin IgG antibody.

172. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain single-chain immunoglobulin IgG antibody comprises one or more selected from human IgG1, human IgG2, human IgG3, human IgG4, mouse IgG1, mouse IgG2a, mouse IgG2b and mouse IgG3.

173. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain includes the single-chain immunoglobulin Fc domain.

174. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain includes the Fc domain of a single-chain immunoglobulin IgG antibody.

175. The fusion polypeptide as claimed in any of the preceding claims, wherein, The Fc domain of the single-chain immunoglobulin IgG antibody includes human IgG1 Fc domain, human IgG2 Fc domain, human IgG3 Fc domain, human IgG4 Fc domain, mouse IgG1 Fc domain, mouse IgG2a Fc domain, mouse IgG2b Fc domain, or mouse IgG3 Fc domain.

176. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain single-chain immunoglobulin Fc fragment contains CH2 and / or CH3 sequences, with the first domain CH2 located between the variable region and the CH3 domain; preferably, the Fc fragment contains any one of the amino acid sequences selected from the group shown: SEQ ID NO: 3, SEQ ID NO:

4.

177. The fusion polypeptide as claimed in any of the preceding claims, wherein, The HCDR1, HCDR2, and / or HCDR3 amino acid sequences or variant sequences thereof in the heavy chain variable region, containing any amino acid sequence selected from the group shown below: SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 64, SEQ ID NO: 65, SEQ ID NO: 66, SEQ ID NO: 69, SEQ ID NO: 70, SEQ ID NO: 71, SEQ ID NO: 74, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 79, SEQ ID NO: 80, SEQ ID NO: 81, SEQ ID NO: 84, SEQ ID NO: 85, SEQ ID NO: 86, SEQ ID NO: 94, SEQ ID NO: 95, SEQ ID NO: 96, SEQ ID NO: 1002, SEQ ID NO: 1003, SEQ ID NO: 1004, SEQ ID NO: 1011, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 64, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 1002, SEQ ID NO: 1003, SEQ ID NO: 1004, SEQ ID NO: 1011, SEQ ID NO: 49, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 79, SEQ ID NO: 70, SEQ ID NO: 71, SEQ ID NO: 74, SEQ ID NO: 1012, SEQ ID NO: 1013, SEQ ID NO: 2007, SEQ ID NO: 2008, SEQ ID NO: 2009, SEQ ID NO: 2012, SEQ ID NO: 2013, SEQ ID NO: 2014; the amino acid sequences or variant sequences of the LCDR1, LCDR2 and / or LCDR3 of the light chain variable region, containing any amino acid sequence selected from the following group: SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 89, SEQ ID NO: 90, SEQ ID NO: 91, SEQ ID NO: 1015, SEQ ID NO: 1016, SEQ ID NO: 1017, SEQ ID NO: 2003, SEQ ID NO: 2004, SEQ ID NO: 2005.

178. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth structure includes a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain variable region VH comprising any amino acid sequence selected from the group consisting of: SEQ ID NO: 47, SEQ ID NO: 58, SEQ ID NO: 63, SEQ ID NO: 68, SEQ ID NO: 73, SEQ ID NO: 78, SEQ ID NO: 83, SEQ ID NO: 93, SEQ ID NO: 1001, SEQ ID NO: 1010, SEQ ID NO: 2006, SEQ ID NO: 2011.

179. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth structure comprises an antibody heavy chain, which comprises an amino acid sequence selected from any of the following groups: SEQ ID NO: 46, SEQ ID NO: 57, SEQ ID NO: 62, SEQ ID NO: 67, SEQ ID NO: 72, SEQ ID NO: 77, SEQ ID NO: 82, SEQ ID NO: 92, SEQ ID NO: 1000, SEQ ID NO: 1005, SEQ ID NO: 1018, SEQ ID NO: 2000, SEQ ID NO: 2010.

180. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth structure includes a light chain variable region VL of an antibody light chain, the antibody light chain comprising any amino acid sequence selected from the group consisting of: SEQ ID NO: 53, SEQ ID NO: 88, SEQ ID NO: 1014, SEQ ID NO: 2002.

181. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain comprises an antibody light chain, which contains an amino acid sequence selected from any of the following groups: SEQ ID NO: 52, SEQ ID NO:

87.

182. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include HCDR1, HCDR2, and HCDR3 of the antibody heavy chain, and LCDR1, LCDR2, and LCDR3 of the antibody light chain, wherein HCDR1, HCDR2, and HCDR3 may each contain amino acid sequences as shown in SEQ ID NO: 59, SEQ ID NO: 60, and SEQ ID NO: 61, respectively, and LCDR1, LCDR2, and LCDR3 may each contain amino acid sequences as shown in SEQ ID NO: 54, SEQ ID NO: 55, and SEQ ID NO: 56, respectively.

183. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth structural domain may include a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain VH may include an amino acid sequence as shown in SEQ ID NO: 58, and the fourth structural domain may include a light chain variable region VL of the antibody light chain, the antibody light chain VL may include an amino acid sequence as shown in SEQ ID NO:

53.

184. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may contain an antibody heavy chain and / or an antibody light chain, wherein the antibody heavy chain may contain an amino acid sequence as shown in SEQ ID NO: 57, and the antibody light chain may contain an amino acid sequence as shown in SEQ ID NO:

52.

185. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include CDR1, CDR2 and CDR3 of a single-domain antibody, wherein CDR1, CDR2 and CDR3 may respectively include the amino acid sequences shown in SEQ ID NO: 48, SEQ ID NO: 49 and SEQ ID NO:

50.

186. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include the heavy chain variable region VHH of a single-domain antibody, and the VHH may contain an amino acid sequence as shown in SEQ ID NO:

47.

187. The fusion polypeptide according to any of the preceding claims, wherein, The fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO:

46.

188. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include CDR1, CDR2 and CDR3 of a single-domain antibody, wherein CDR1, CDR2 and CDR3 may respectively include the amino acid sequences shown in SEQ ID NO: 64, SEQ ID NO: 65 and SEQ ID NO:

66.

189. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include the heavy chain variable region VHH of a single-domain antibody, and the VHH may contain an amino acid sequence as shown in SEQ ID NO:

63.

190. The fusion polypeptide according to any of the preceding claims, wherein, The fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO:

62.

191. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include CDR1, CDR2 and CDR3 of a single-domain antibody, wherein CDR1, CDR2 and CDR3 may respectively include the amino acid sequences shown in SEQ ID NO: 69, SEQ ID NO: 70 and SEQ ID NO:

71.

192. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include the heavy chain variable region VHH of a single-domain antibody, and the VHH may contain an amino acid sequence as shown in SEQ ID NO:

68.

193. The fusion polypeptide according to any of the preceding claims, wherein, The fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO:

67.

194. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may comprise CDR1, CDR2, and CDR3 of a single-domain antibody, wherein CDR1, CDR2, and CDR3 may comprise amino acid sequences as shown in SEQ ID NO: 74, SEQ ID NO: 75, and SEQ ID NO: 76, respectively.

195. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include the heavy chain variable region VHH of a single-domain antibody, and the VHH may contain an amino acid sequence as shown in SEQ ID NO:

73.

196. The fusion polypeptide according to any of the preceding claims, wherein, The fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO:

72.

197. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include CDR1, CDR2 and CDR3 of a single-domain antibody, wherein CDR1, CDR2 and CDR3 may respectively include the amino acid sequences shown in SEQ ID NO: 79, SEQ ID NO: 80 and SEQ ID NO:

81.

198. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include the heavy chain variable region VHH of a single-domain antibody, and the VHH may contain an amino acid sequence as shown in SEQ ID NO:

78.

199. The fusion polypeptide according to any of the preceding claims, wherein, The fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO:

77.

200. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include CDR1, CDR2 and CDR3 of a single-domain antibody, wherein CDR1, CDR2 and CDR3 may respectively include the amino acid sequences shown in SEQ ID NO: 84, SEQ ID NO: 85 and SEQ ID NO:

86.

201. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include the heavy chain variable region VHH of a single-domain antibody, and the VHH may contain an amino acid sequence as shown in SEQ ID NO:

83.

202. The fusion polypeptide according to any of the preceding claims, wherein, The fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO:

82.

203. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include HCDR1, HCDR2, and HCDR3 of the antibody heavy chain, and LCDR1, LCDR2, and LCDR3 of the antibody light chain, wherein HCDR1, HCDR2, and HCDR3 may each contain amino acid sequences as shown in SEQ ID NO: 94, SEQ ID NO: 95, and SEQ ID NO: 96, and LCDR1, LCDR2, and LCDR3 may each contain amino acid sequences as shown in SEQ ID NO: 89, SEQ ID NO: 90, and SEQ ID NO: 91, respectively.

204. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth structural domain may include a heavy chain variable region VH of the antibody heavy chain, the antibody heavy chain VH may include an amino acid sequence as shown in SEQ ID NO: 93, and the fourth structural domain may include a light chain variable region VL of the antibody light chain, the antibody light chain VL may include an amino acid sequence as shown in SEQ ID NO:

88.

205. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may contain an antibody heavy chain and / or an antibody light chain, wherein the antibody heavy chain may contain an amino acid sequence as shown in SEQ ID NO: 92, and the antibody light chain may contain an amino acid sequence as shown in SEQ ID NO:

87.

206. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include CDR1, CDR2 and CDR3 of a single-domain antibody, wherein CDR1, CDR2 and CDR3 may respectively include the amino acid sequences shown in SEQ ID NO: 1002, SEQ ID NO: 1003 and SEQ ID NO: 1004.

207. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include the heavy chain variable region VHH of a single-domain antibody, and the VHH may contain an amino acid sequence as shown in SEQ ID NO: 1001.

208. The fusion polypeptide according to any of the preceding claims, wherein, The fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 1000 or SEQ ID NO: 1005.

209. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may comprise the heavy chains HCDR1, HCDR2, and HCDR3 and the light chains LCDR1, LCDR2, and LCDR3 of the scFv antibody, wherein HCDR1, HCDR2, and HCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 1011, SEQ ID NO: 1012, and SEQ ID NO: 1013, respectively, and LDR1, LCDR2, and LCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 1015, SEQ ID NO: 1016, and SEQ ID NO: 1017, respectively.

210. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include the heavy chain variable region VH and the light chain variable region VL of the scFv antibody. The VH may contain the amino acid sequence shown in SEQ ID NO: 1010, and the VL may contain the amino acid sequence shown in SEQ ID NO: 1014.

211. The fusion polypeptide according to any of the preceding claims, wherein, The fourth domain may contain an scFv antibody, which may contain an amino acid sequence as shown in SEQ ID NO: 1009 or SEQ ID NO: 1018.

212. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may comprise the heavy chains HCDR1, HCDR2, and HCDR3 and the light chains LCDR1, LCDR2, and LCDR3 of the scFv antibody, wherein HCDR1, HCDR2, and HCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 2007, SEQ ID NO: 2008, and SEQ ID NO: 2009, respectively, and LDR1, LCDR2, and LCDR3 may comprise the amino acid sequences shown in SEQ ID NO: 2003, SEQ ID NO: 2004, and SEQ ID NO: 2005, respectively.

213. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include the heavy chain variable region VH and the light chain variable region VL of the scFv antibody. The VH may contain the amino acid sequence shown in SEQ ID NO: 2006, and the VL may contain the amino acid sequence shown in SEQ ID NO: 2002.

214. The fusion polypeptide according to any of the preceding claims, wherein, The fourth domain may contain an scFv antibody, which may contain an amino acid sequence as shown in SEQ ID NO: 2001 or SEQ ID NO: 2000.

215. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include CDR1, CDR2 and CDR3 of a single-domain antibody, wherein CDR1, CDR2 and CDR3 may respectively include the amino acid sequences shown in SEQ ID NO: 2012, SEQ ID NO: 2013 and SEQ ID NO: 2014.

216. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth domain may include the heavy chain variable region VHH of a single-domain antibody, and the VHH may contain an amino acid sequence as shown in SEQ ID NO: 2011.

217. The fusion polypeptide according to any of the preceding claims, wherein, The fourth domain may comprise a heavy chain of a single-domain antibody, the heavy chain comprising an amino acid sequence as shown in SEQ ID NO: 2010.

218. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth structural domain does not contain light chains.

219. The fusion polypeptide as claimed in any of the preceding claims, wherein, The aforementioned fourth domain fusion peptide does not contain the CH1 domain.

220. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain and the fourth structural domain are directly or indirectly connected.

221. The fusion polypeptide as claimed in any of the preceding claims, wherein, The heavy chain Fc of the first structural domain is directly or indirectly connected to the heavy chain Fc of the fourth structural domain.

222. The fusion polypeptide of claim 221, wherein, The heavy chain Fc segment of the first structural domain is connected to the heavy chain Fc of the fourth structural domain by a disulfide bond.

223. The fusion polypeptide according to any one of claims 221-222, wherein, The heavy chain of the first structural domain forms a heterodimer with the heavy chain of the fourth structural domain.

224. The fusion polypeptide according to claims 221-223, wherein, The heavy chain Fc segment of the first structural domain and the heavy chain Fc segment of the fourth structural domain are paired and connected by a pestle-mortar structure.

225. The fusion polypeptide of claim 224, wherein, Knob-into-hole pairing involves one or more substitutions in the Fc segment of the heavy chain, which form heterodimer pairings between heavy chains.

226. The fusion polypeptide according to any one of claims 223-225, wherein, CH3 in the first structural domain and CH3 in the fourth structural domain form a pestle-mortar substitution pair.

227. The fusion polypeptide of claim 226, wherein, The T366 and / or Y407 amino acid residues in one of the CH3 domains of the first and fourth domains are replaced, and the L368 amino acid residue in the other CH3 domain is replaced.

228. The fusion polypeptide according to any one of claims 1-220, wherein, The antigen-binding fragment of the first domain is directly or indirectly connected to the fourth domain.

229. The fusion polypeptide of claim 228, wherein, The N-terminus of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the fourth domain; or the C-terminus of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the fourth domain.

230. The fusion polypeptide according to any one of claims 228-229, wherein, The heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the heavy chain of the fourth domain; or the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the heavy chain of the fourth domain; or the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the light chain of the fourth domain; or the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the light chain of the fourth domain.

231. The fusion polypeptide according to claims 228-230, wherein, The C-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the fourth domain; or the C-terminus of the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the fourth domain; or the C-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the fourth domain; or the N-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the fourth domain; or the N-terminus of the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the fourth domain; or the N-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the fourth domain; or the N-terminus of the heavy chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the fourth domain; or the N-terminus of the light chain of the first domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the fourth domain.

232. The fusion polypeptide according to any one of claims 1-220, wherein, The first domain is directly or indirectly connected to the antigen-binding fragment of the fourth domain.

233. The fusion polypeptide of claim 232, wherein, The N-terminus of the first domain is directly or indirectly connected to the C-terminus of the antigen-binding fragment of the fourth domain; or the C-terminus of the first domain is directly or indirectly connected to the N-terminus of the antigen-binding fragment of the fourth domain.

234. The fusion polypeptide according to any one of claims 232-233, wherein, The heavy chain of the first domain is directly or indirectly connected to the heavy chain of the antigen-binding fragment of the fourth domain; or the light chain of the first domain is directly or indirectly connected to the heavy chain of the antigen-binding fragment of the fourth domain; or the heavy chain of the first domain is directly or indirectly connected to the light chain of the antigen-binding fragment of the fourth domain; or the light chain of the first domain is directly or indirectly connected to the light chain of the antigen-binding fragment of the fourth domain.

235. The fusion polypeptide according to any one of claims 232-234, wherein, The C-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the first domain; or the C-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the first domain; or the C-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the first domain; or the C-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the first domain; or the N-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the first domain; or the N-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the first domain; or the N-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the first domain; or the N-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the first domain.

236. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth structural domain is directly or indirectly connected to the third structural domain.

237. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth structural domain heavy chain is directly or indirectly connected to the third structural domain. For example, the C-end of the fourth structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, or the N-end of the fourth structural domain heavy chain is directly or indirectly connected to the C-end of the third structural domain.

238. The fusion polypeptide as claimed in any of the preceding claims, wherein, The light chain of the fourth structural domain is directly or indirectly connected to the third structural domain. For example, the C-end of the light chain of the fourth structural domain is directly or indirectly connected to the N-end of the third structural domain, or the N-end of the light chain of the fourth structural domain is directly or indirectly connected to the C-end of the third structural domain.

239. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second and fourth structural domains are directly or indirectly connected.

240. The fusion polypeptide as claimed in any of the preceding claims, wherein, The heavy chain Fc of the second structural domain is directly or indirectly connected to the heavy chain Fc of the fourth structural domain.

241. The fusion polypeptide of claim 240, wherein, The heavy chain Fc segment of the second structural domain is connected to the heavy chain Fc of the fourth structural domain by a disulfide bond.

242. The fusion polypeptide of claim 240, wherein, The heavy chain of the second structural domain forms a heterodimer with the heavy chain of the fourth structural domain.

243. The fusion polypeptide of claim 242, wherein, The heavy chain Fc segment of the second structural domain and the heavy chain Fc segment of the fourth structural domain are paired and connected by a pestle-mortar structure.

244. The fusion polypeptide according to any one of claims 242-243, wherein, Knob-into-hole pairing involves one or more substitutions in the Fc segment of the heavy chain, which form heterodimer pairings between heavy chains.

245. The fusion polypeptide according to any one of claims 242-244, wherein, The CH3 in the second domain and the CH3 in the fourth domain form a pestle-mortar substitution pair.

246. The fusion polypeptide of claim 245, wherein, The T366 and / or Y407 amino acid residues in one of the CH3 domains of the second and fourth domains are replaced, and the L368 amino acid residue in the other CH3 domain is replaced.

247. The fusion polypeptide as claimed in any of the preceding claims, wherein, The antigen-binding fragment of the second domain is directly or indirectly linked to the fourth domain.

248. The fusion polypeptide of claim 247, wherein, The N-terminus of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the fourth domain; or the C-terminus of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the fourth domain.

249. The fusion polypeptide according to any one of claims 247-248, wherein, The heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the heavy chain of the fourth domain; or the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the heavy chain of the fourth domain; or the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the light chain of the fourth domain; or the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the light chain of the fourth domain.

250. The fusion polypeptide according to claims 247-249, wherein, The C-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the fourth domain; or the C-terminus of the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the fourth domain; or the C-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the fourth domain; or the N-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the fourth domain; or the N-terminus of the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the fourth domain; or the N-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the fourth domain; or the N-terminus of the heavy chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the fourth domain; or the N-terminus of the light chain of the second domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the fourth domain.

251. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second domain is directly or indirectly connected to the antigen-binding fragment of the fourth domain.

252. The fusion polypeptide of claim 251, wherein, The N-terminus of the second domain is directly or indirectly connected to the C-terminus of the antigen-binding fragment of the fourth domain; or the C-terminus of the second domain is directly or indirectly connected to the N-terminus of the antigen-binding fragment of the fourth domain.

253. The fusion polypeptide according to any one of claims 251-252, wherein, The heavy chain of the second domain is directly or indirectly connected to the heavy chain of the antigen-binding fragment of the fourth domain; or the light chain of the second domain is directly or indirectly connected to the heavy chain of the antigen-binding fragment of the fourth domain; or the heavy chain of the second domain is directly or indirectly connected to the light chain of the antigen-binding fragment of the fourth domain; or the light chain of the second domain is directly or indirectly connected to the light chain of the antigen-binding fragment of the fourth domain.

254. The fusion polypeptide according to any one of claims 251-253, wherein, The C-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the second domain; or the C-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the heavy chain of the second domain; or the C-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the N-terminus of the light chain of the second domain; or the N-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the second domain; or the N-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the second domain; or the N-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the heavy chain of the second domain; or the N-terminus of the heavy chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the second domain; or the N-terminus of the light chain of the fourth domain antigen-binding fragment is directly or indirectly connected to the C-terminus of the light chain of the second domain.

255. The fusion polypeptide according to any one of claims 164-254, wherein the fourth structural domain may be absent.

256. The fusion polypeptide of any of the preceding claims further comprises a fifth domain, which is capable of conditionally masking the CD3 binding domain in the first domain, or the fifth domain may be absent.

257. The fusion polypeptide of claim 256, wherein, The fifth domain includes a masking peptide fragment that can alter the affinity of the first domain for binding to CD3.

258. The fusion polypeptide according to any one of claims 256-257, wherein, The fifth domain masking peptide fragment comprises a polypeptide sequence selected from the following: SEQ ID No:404, SEQ ID No:406, SEQ ID No:407, SEQ ID No:408, SEQ ID No:409, SEQ ID No:410, SEQ ID No:412, SEQ ID No:414, SEQ ID No:415, SEQ ID No:424, SEQ ID No:425, SEQ ID No:426, SEQ ID No:427, SEQ ID No:428, SEQ ID No:403, SEQ ID No:405, SEQ ID No:411, SEQ ID No:413, SEQ ID No:416, SEQ ID No:417, SEQ ID No:418, SEQ ID No:432, SEQ ID No:433, SEQ ID No:434, SEQ ID No:419, SEQ ID No:420, SEQ ID No:421, SEQ ID No:422, SEQ ID No:404, SEQ ID No:405, SEQ ID No:416, SEQ ID No:417, SEQ ID No:418, SEQ ID No:432, SEQ ID No:433, SEQ ID No:434, SEQ ID No:419, SEQ ID No:420, SEQ ID No:421, SEQ ID No:422, SEQ ID No:423, SEQ ID No:42 ...25, No:423, SEQ ID No:401, SEQ ID No:402, SEQ ID No:429, SEQ ID No:430, SEQ ID No:

431.

259. The fusion polypeptide according to any one of claims 256-258, wherein, The fifth domain further includes an enzyme cleavage linker, through which the masking peptide fragment of the fifth domain is linked to the first domain, the second domain, or the fourth domain.

260. The fusion polypeptide of claim 259, wherein, The enzyme-ligand contains a protease cleavage site fragment.

261. The fusion polypeptide according to any one of claims 259-260, wherein, The enzyme cleavage linker contains one, two, three, four, five or more protease cleavage site fragments selected from SEQ ID NO:3000-3036.

262. The fusion polypeptide according to any one of claims 259-261, wherein, The enzyme-ligand further includes 0, 1, 2, 3, 4, 5, or more linker amino acid sequences selected from the following: GS, GGS, GSGS, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO:

10. The linker amino acid sequence is located between two protease cleavage sites, between a masking peptide fragment and a protease cleavage site fragment, or between a protease cleavage site fragment and a first, second, or fourth domain.

263. The fusion polypeptide according to any one of claims 259-262, wherein, The masking peptide fragment of the fifth structural domain is directly or indirectly linked to the enzyme-ligating linker; preferably, the C-terminus of the masking peptide fragment of the fifth structural domain is directly or indirectly linked to the N-terminus of the enzyme-ligating linker, or the N-terminus of the masking peptide fragment of the fifth structural domain is directly or indirectly linked to the C-terminus of the enzyme-ligating linker.

264. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first and fifth structural domains are directly or indirectly connected.

265. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain heavy chain is directly or indirectly connected to the fifth structural domain; preferably, the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the fifth structural domain, or the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain.

266. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain light chain is directly or indirectly connected to the fifth structural domain; preferably, the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the fifth structural domain, or the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the fifth structural domain.

267. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second and fifth structural domains are directly or indirectly connected.

268. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structural domain heavy chain is directly or indirectly connected to the fifth structural domain; preferably, the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the fifth structural domain, or the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain.

269. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structural domain light chain is directly or indirectly connected to the fifth structural domain. Preferably, the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the fifth structural domain, or the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the fifth structural domain.

270. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth and fifth structural domains are directly or indirectly connected.

271. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth structural domain heavy chain is directly or indirectly connected to the fifth structural domain; preferably, the C-end of the fourth structural domain heavy chain is directly or indirectly connected to the N-end of the fifth structural domain, or the N-end of the fourth structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain.

272. The fusion polypeptide as claimed in any of the preceding claims, wherein, The light chain of the fourth structural domain is directly or indirectly connected to the fifth structural domain; preferably, the C-end of the light chain of the fourth structural domain is directly or indirectly connected to the N-end of the fifth structural domain, or the N-end of the light chain of the fourth structural domain is directly or indirectly connected to the C-end of the fifth structural domain.

273. The fusion polypeptide of any of the preceding claims further comprises a sixth domain: the sixth domain is capable of binding CD28 and / or CTLA4, or the sixth domain may be absent.

274. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain contains CD86 or CD80 or their functionally active fragments, or variants thereof.

275. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain is selected from the group consisting of CD86 or CD80 derived from humans or mice, or their functionally active fragments or variants thereof.

276. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain contains the extracellular domain of CD86 or CD80, or a functionally active fragment thereof, or a variant thereof.

277. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain contains the IgV of CD86 or CD80, or a functionally active fragment thereof, or a variant thereof.

278. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain contains a CD86 variant polypeptide, which contains an amino acid substitution mutation of human CD86.

279. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain comprises a CD86 variant polypeptide, which comprises an IgV domain amino acid substitution mutant of CD86 and / or an extracellular domain amino acid substitution mutant of human CD86.

280. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain comprises a CD86 variant polypeptide, which comprises an IgV domain amino acid substitution mutant of CD86. The mutation site of the CD86 IgV domain amino acid substitution mutant comprises one, two, three, four, five, or more amino acid site mutations selected from the group consisting of: A13I, A13L, A13F, A13M, Q25A, Q25I, Q25V, Q25F, Q25M, F33A, F33L, F33V, F33M, M60R, I89A, I89L, I89V, I89F, I89M, H90I, H90V, H90M, H90F.

281. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain comprises a CD86 variant polypeptide, which contains an IgV domain amino acid substitution mutant of CD86, wherein the amino acid substitution mutant comprises the combination shown below: Q25I / F33L / H90I, Q25V / F33L / H90I, Q25I / F33V / H90I, Q25V / F33V / H90I, Q25I / F33L / H90V, Q25V / F33L / H90V, Q25I / F33V / H90V, Q25V / F33V / H90V, A13L / Q25I / F33L / H90I, A13I / Q25I / F33L / H90I, A 13L / Q25V / F33L / H90I, A13I / Q25V / F33L / H90I, Q25I / F33L / I89L / H90I, Q25I / F33L / M60R / H90 I. Q25V / F33L / I89L / H90I, Q25V / F33L / M60R / H90I, Q25F / F33L / H90I, Q25I / F33L / H90F, Q25I / F33A / H90I, Q25I / H90I, Q25I, H90I, Q25V / H90V, Q25V / H90I, Q25F / H90I, Q25F / H90V, A13F / Q 25I / F33L / H90I, A13M / Q25I / F33L / H90I, Q25A / F33L / H90I, Q25M / F33L / H90I, Q25I / F33M / H90I, Q25I / F33L / I89V / H90I, Q25I / F33L / I89F / H90I, Q25I / F33L / I89M / H90I and Q25I / F33L / H90M.

282. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain comprises a CD86 variant polypeptide, which contains the CD86 IgV domain amino acid substitution mutant Q25I / F33L / H90I.

283. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain comprises a CD86 variant polypeptide, which comprises an extracellular domain amino acid substitution mutant of CD86, wherein the extracellular domain amino acid substitution mutant of CD86 comprises one, two, three, four, five or more amino acid site mutations selected from the group consisting of: A13I, A13L, A13F, A13M, Q25A, Q25I, Q25V, Q25F, Q25M, F33A, F33L, F33V, F33M, M60R, I89A, I89L, I89V, I89F, I89M, H90I, H90V, H90M, H90F.

284. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain comprises an extracellular domain amino acid substitution mutant of CD86, wherein the amino acid substitution mutant comprises the following combinations: Q25I / F33L / H90I, 25V / F33L / H90I, Q25I / F33V / H90I, Q25V / F33V / H90I, Q25I / F33L / H90V, Q25V / F33L / H90V, Q25I / F33V / H 90V, Q25V / F33V / H90V, A13L / Q25I / F33L / H90I, A13I / Q25I / F33L / H90I, A13L / Q25V / F33L / H90I, A13I / Q25V / F33L / H90I, Q25I / F33L / I89L / H90I, Q25I / F33L / M60R / H90I, Q25V / F33L / I89L / H90I, Q25V / F33L / M60R / H90I, Q25F / F33L / H90I, Q25I / F33L / H90F, Q25I / F33A / H90 I, Q25I / H90I, Q25I, H90I, Q25V / H90V, Q25V / H90I, Q25F / H90I, Q25F / H90V, A13F / Q25I / F3 3L / H90I, A13M / Q25I / F33L / H90I, Q25A / F33L / H90I, Q25M / F33L / H90I, Q25I / F33M / H90I, Q 25I / F33L / I89V / H90I, Q25I / F33L / I89F / H90I, Q25I / F33L / I89M / H90I and Q25I / F33L / H90M.

285. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain comprises an extracellular domain amino acid substitution mutant of CD86, wherein the amino acid substitution mutant comprises the combination shown below: Q25I / F33L / H90I.

286. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain comprises an amino acid sequence selected from SEQ ID NO: 97 to SEQ ID NO:

165.

287. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain contains a CD80 variant polypeptide, and the mutant contains an amino acid substitution mutation of human CD80.

288. The fusion polypeptide as claimed in any of the preceding claims, wherein, The sixth domain comprises a CD80 variant polypeptide, which comprises an IgV domain amino acid substitution mutant of CD80 and / or an extracellular domain amino acid substitution mutant of human CD80.

289. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain and the sixth structural domain are directly or indirectly connected.

290. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain heavy chain is directly or indirectly connected to the sixth structural domain. For example, the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain, or the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the sixth structural domain.

291. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain light chain is directly or indirectly connected to the sixth structural domain. For example, the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the sixth structural domain, or the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the sixth structural domain.

292. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second and sixth structural domains are directly or indirectly connected.

293. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structural domain heavy chain is directly or indirectly connected to the sixth structural domain. For example, the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain, or the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the sixth structural domain.

294. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structural domain light chain is directly or indirectly connected to the sixth structural domain. For example, the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the sixth structural domain, or the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the sixth structural domain.

295. The fusion polypeptide as claimed in any of the preceding claims, wherein, The fourth and sixth structural domains are directly or indirectly connected.

296. The fusion polypeptide as claimed in any of the preceding claims, wherein, The heavy chain of the fourth structural domain is directly or indirectly connected to the sixth structural domain. For example, the C-end of the heavy chain of the fourth structural domain is directly or indirectly connected to the N-end of the sixth structural domain, or the N-end of the heavy chain of the fourth structural domain is directly or indirectly connected to the C-end of the sixth structural domain.

297. The fusion polypeptide as claimed in any of the preceding claims, wherein, The light chain of the fourth structural domain is directly or indirectly connected to the sixth structural domain. For example, the C-end of the light chain of the fourth structural domain is directly or indirectly connected to the N-end of the sixth structural domain, or the N-end of the light chain of the fourth structural domain is directly or indirectly connected to the C-end of the sixth structural domain.

298. The fusion polypeptide as claimed in any of the preceding claims, wherein, The third and sixth structural domains are directly or indirectly connected.

299. The fusion polypeptide as claimed in any of the preceding claims, wherein the fusion polypeptide comprises a first domain, a second domain, a third domain, and a sixth domain, wherein: The first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

300. The fusion polypeptide of claim 299, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain.

301. The fusion polypeptide of claim 300, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the third structural domain, and the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the third structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain; or Alternatively, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the sixth structural domain.

302. The fusion polypeptide of claim 299, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain; and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the second structural domain light chain is directly or indirectly connected to the sixth structural domain.

303. The fusion polypeptide of claim 302, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the third structural domain, and the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the third structural domain, and the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the sixth structural domain; or Alternatively, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the sixth structural domain.

304. The fusion polypeptide of claim 299, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain; and the first structural domain light chain is directly or indirectly connected to the third structural domain, and the second structural domain light chain is directly or indirectly connected to the sixth structural domain.

305. The fusion polypeptide of claim 304, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the third structural domain, and the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the third structural domain, and the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the sixth structural domain; or Alternatively, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the sixth structural domain.

306. The fusion polypeptide of claim 299, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain; and the first structural domain light chain is directly or indirectly connected to the third structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain.

307. The fusion polypeptide of claim 306, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the third structural domain, and the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the third structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain; or Alternatively, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain; or, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the sixth structural domain.

308. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain is directly or indirectly connected to the fourth structural domain, and the fourth structural domain is directly or indirectly connected to the third structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

309. The fusion polypeptide of claim 308, wherein, The second structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fourth structural domain; the fourth structural domain heavy chain is directly or indirectly connected to the third structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain.

310. The fusion polypeptide of claim 309, wherein, The second structural domain is directly or indirectly connected to the fourth structural domain; and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the fourth structural domain; and the C-end of the heavy chain of the fourth structural domain is directly or indirectly connected to the N-end of the third structural domain; and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the sixth structural domain.

311. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain is directly or indirectly connected to the third structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

312. The fusion polypeptide of claim 311, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain.

313. The fusion polypeptide of claim 312, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the N end of the heavy chain of the first structural domain is directly or indirectly connected to the C end of the fourth structural domain, and the C end of the heavy chain of the first structural domain is directly or indirectly connected to the N end of the third structural domain, and the C end of the heavy chain of the second structural domain is directly or indirectly connected to the N end of the sixth structural domain.

314. The fusion polypeptide of claim 311, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the light chain of the first structural domain is directly or indirectly connected to the fourth structural domain, and the heavy chain of the first structural domain is directly or indirectly connected to the third structural domain, and the heavy chain of the second structural domain is directly or indirectly connected to the sixth structural domain.

315. The fusion polypeptide of claim 314, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the N-end of the light chain of the first structural domain is directly or indirectly connected to the C-end of the fourth structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the third structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the sixth structural domain; or, the first structural domain is directly or indirectly connected to the second structural domain, and the C-end of the light chain of the first structural domain is directly or indirectly connected to the N-end of the fourth structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the third structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the sixth structural domain.

316. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain is directly or indirectly connected to the second structural domain; and the first structural domain is directly or indirectly connected to the third structural domain; and the second structural domain is directly or indirectly connected to the fourth structural domain; and the second structural domain is directly or indirectly connected to the sixth structural domain.

317. The fusion polypeptide of claim 316, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain.

318. The fusion polypeptide of claim 317, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the heavy chain of the second structural domain is directly or indirectly connected to the C-end of the fourth structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the sixth structural domain.

319. The fusion polypeptide of claim 316, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the heavy chain of the first structural domain is directly or indirectly connected to the third structural domain, and the light chain of the second structural domain is directly or indirectly connected to the fourth structural domain, and the heavy chain of the second structural domain is directly or indirectly connected to the sixth structural domain.

320. The fusion polypeptide of claim 319, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the light chain of the second structural domain is directly or indirectly connected to the C-end of the fourth structural domain, and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the sixth structural domain; or, the first structural domain is directly or indirectly connected to the second structural domain; and the C-end of the heavy chain of the first structural domain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the light chain of the second structural domain is directly or indirectly connected to the N-end of the fourth structural domain; and the C-end of the heavy chain of the second structural domain is directly or indirectly connected to the N-end of the sixth structural domain.

321. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain is directly or indirectly connected to the second structural domain; and the first structural domain or the second structural domain is directly or indirectly connected to the fifth structural domain.

322. The fusion polypeptide of claim 321, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain or the second structural domain heavy chain is directly or indirectly connected to the fifth structural domain.

323. The fusion polypeptide of claim 322, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N end of the first structural domain heavy chain or the N end of the second structural domain heavy chain is directly or indirectly connected to the C end of the fifth structural domain.

324. The fusion polypeptide of claim 321, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain light chain or the second structural domain light chain is directly or indirectly connected to the fifth structural domain.

325. The fusion polypeptide of claim 324, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N end of the first structural domain light chain or the N end of the second structural domain light chain is directly or indirectly connected to the C end of the fifth structural domain.

326. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structural domain is directly or indirectly connected to the fourth structural domain; and the first structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain is directly or indirectly connected to the fifth structural domain.

327. The fusion polypeptide of claim 326, wherein, The second structural domain heavy chain is directly or indirectly connected to the fourth structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain; preferably, the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the fourth structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain.

328. The fusion polypeptide of claim 326, wherein, The second structural domain heavy chain is directly or indirectly connected to the fourth structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain; preferably, the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the fourth structural domain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the fifth structural domain.

329. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain is directly or indirectly connected to the fifth structural domain.

330. The fusion polypeptide of claim 329, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain light chain is directly or indirectly connected to the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the fourth structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain; or preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the fourth structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain.

331. The fusion polypeptide of claim 329, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain light chain is directly or indirectly connected to the fourth structural domain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the fourth structural domain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the fifth structural domain.

332. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain is directly or indirectly connected to the second structural domain; and the first structural domain is directly or indirectly connected to the fifth structural domain, and the second structural domain is directly or indirectly connected to the fourth structural domain.

333. The fusion polypeptide of claim 332, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end domain of the fifth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the fourth structural domain.

334. The fusion polypeptide of claim 332, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end domain of the fifth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the fourth structural domain.

335. The fusion polypeptide of claim 332, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, and the second structural domain light chain is directly or indirectly connected to the fourth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end domain of the fifth structural domain, and the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the fourth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end domain of the fifth structural domain, and the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the fourth structural domain.

336. The fusion polypeptide of claim 332, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain, and the second structural light chain is directly or indirectly connected to the fourth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end domain of the fifth structural domain, and the C-end of the second structural domain light chain is directly or indirectly connected to the N-end of the fourth structural domain; or preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain light chain is directly or indirectly connected to the N-end domain of the fifth structural domain, and the N-end of the second structural domain light chain is directly or indirectly connected to the C-end of the fourth structural domain.

337. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain is directly or indirectly connected to the second structural domain; and the first structural domain is directly or indirectly connected to the third structural domain, and the first structural domain is directly or indirectly connected to the fifth structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

338. The fusion polypeptide of claim 337, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

339. The fusion polypeptide of claim 337, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the fifth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

340. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain, and the first structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain is directly or indirectly connected to the fifth structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

341. The fusion polypeptide of claim 340, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the first structural domain light chain is directly or indirectly connected to the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the fourth structural domain, the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

342. The fusion polypeptide of claim 340, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the first structural domain light chain is directly or indirectly connected to the fourth structural domain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, the C-end of the first structural domain light chain is directly or indirectly connected to the N-end of the fourth structural domain, the N-end of the first structural domain light chain is directly or indirectly connected to the C-end of the fifth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

343. The fusion polypeptide as claimed in any of the preceding claims, wherein, The second structural domain is directly or indirectly connected to the fourth structural domain; and the first structural domain is directly or indirectly connected to the fourth structural domain, and the first structural domain is directly or indirectly connected to the fifth structural domain, and the second structural domain is directly or indirectly connected to the third structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

344. The fusion polypeptide of claim 343, wherein, The second structural domain is directly or indirectly connected to the fourth structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, the second structural domain heavy chain is directly or indirectly connected to the third structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the second structural domain is directly or indirectly connected to the fourth structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the fourth structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

345. The fusion polypeptide of claim 343, wherein, The second structural domain is directly or indirectly connected to the heavy chain of the fourth structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the first structural domain light chain is directly or indirectly connected to the fifth structural domain, the second structural domain heavy chain is directly or indirectly connected to the third structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the second structural domain is directly or indirectly connected to the heavy chain of the fourth structural domain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the fourth structural domain, and the N-end of the first structural domain light chain is directly or indirectly connected to the fifth structural domain, the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

346. The fusion polypeptide as claimed in any of the preceding claims, wherein, The first structural domain is directly or indirectly connected to the second structural domain, and the first structural domain is directly or indirectly connected to the third structural domain, and the first structural domain is directly or indirectly connected to the fifth structural domain, and the second structural domain is directly or indirectly connected to the fourth structural domain, and the second structural domain is directly or indirectly connected to the sixth structural domain.

347. The fusion polypeptide of claim 346, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the fourth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain, and the N-end of the second structural domain heavy chain is directly or indirectly connected to the C-end of the fourth structural domain, and the C-end of the second structural domain heavy chain is directly or indirectly connected to the N-end of the sixth structural domain.

348. The fusion polypeptide of claim 346, wherein, The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the third structural domain, and the first structural domain heavy chain is directly or indirectly connected to the fifth structural domain, and the second structural domain light chain is directly or indirectly connected to the fourth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the sixth structural domain; preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the C-end of the first structural domain heavy chain is directly or indirectly connected to the N-end of the third structural domain, and the N-end of the first structural domain heavy chain is directly or indirectly connected to the C-end of the fifth structural domain. The first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the second structural domain heavy chain is directly or indirectly connected to the N end of the sixth structural domain; or preferably, the first structural domain heavy chain is directly or indirectly connected to the second structural domain heavy chain, and the first structural domain heavy chain is directly or indirectly connected to the N end of the third structural domain, and the first structural domain heavy chain is directly or indirectly connected to the C end of the fifth structural domain, and the second structural domain light chain is directly or indirectly connected to the N end of the fourth structural domain, and the second structural domain heavy chain is directly or indirectly connected to the N end of the sixth structural domain.

349. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes a heavy chain with a first structural domain from its N-terminus to its C-terminus; the third polypeptide includes a heavy chain with a second structural domain from its N-terminus to its C-terminus; and the fourth polypeptide includes a light chain with a second structural domain from its N-terminus to its C-terminus. The first polypeptide and the fourth polypeptide may or may not be present.

350. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes a heavy chain with a structural domain, a linker, and a third structural domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a heavy chain with a second structural domain from its N-terminus to its C-terminus; and the fourth polypeptide includes a light chain with a second structural domain from its N-terminus to its C-terminus; wherein the first polypeptide and the fourth polypeptide may or may not be present.

351. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes a heavy chain with a structural domain from its N-terminus to its C-terminus; the third polypeptide includes, sequentially from its N-terminus to its C-terminus, a heavy chain with a second structural domain, a linker, and a sixth structural domain; the fourth polypeptide includes a light chain with a second structural domain from its N-terminus to its C-terminus; wherein the first polypeptide and the fourth polypeptide may or may not be present.

352. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes a heavy chain with a first structural domain, a linker, and a third structural domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a heavy chain with a second structural domain, a linker, and a sixth structural domain sequentially from its N-terminus to its C-terminus; and the fourth polypeptide includes a light chain with a second structural domain from its N-terminus to its C-terminus; wherein the first polypeptide and the fourth polypeptide may or may not be present.

353. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes, from its N-terminus to its C-terminus, a heavy chain with a first structural domain, a CD3 antigen-binding fragment, a linker, a heavy chain with a fourth structural domain, a linker, and a third structural domain; the third polypeptide includes, from its N-terminus to its C-terminus, a heavy chain with a second structural domain, a linker, and a sixth structural domain; the fourth polypeptide includes a light chain with a second structural domain from its N-terminus to its C-terminus; and the fifth polypeptide includes a light chain with a fourth structural domain from its N-terminus to its C-terminus. The first, fourth, and fifth polypeptides may or may not be present.

354. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a light chain with a first structural domain, a linker, and a heavy chain with a fourth structural domain; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain with a first structural domain, a linker, and a third structural domain; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain with a second structural domain, a linker, and a sixth structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain with a second structural domain; and the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain with a fourth structural domain; wherein the fourth and fifth polypeptides may or may not be present.

355. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fourth domain heavy chain, a TAA antigen-binding fragment, a linker, a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide, the fourth polypeptide, and the fifth polypeptide may or may not be present.

356. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a fourth structural domain (TAA antigen-binding fragment), a linker, and a light chain of the first structural domain; the second polypeptide comprises, from N-terminus to C-terminus, a first structural domain (heavy chain), a linker, and a third structural domain; the third polypeptide comprises, from N-terminus to C-terminus, a second structural domain (heavy chain), a linker, and a sixth structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a second structural domain (light chain); and the fifth polypeptide comprises, from N-terminus to C-terminus, a fourth structural domain (light chain); wherein the fourth and fifth polypeptides may or may not be present.

357. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes a heavy chain with a first structural domain, a linker, and a third structural domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a TAA antigen-binding fragment with a fourth structural domain, a linker, a heavy chain with a second structural domain, a linker, and a sixth structural domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a light chain with a second structural domain from its N-terminus to its C-terminus; and the fifth polypeptide includes a light chain with a fourth structural domain from its N-terminus to its C-terminus; wherein the first polypeptide, the fourth polypeptide, and the fifth polypeptide may or may not be present.

358. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes a heavy chain with a first structural domain, a linker, and a third structural domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a heavy chain with a second structural domain, a linker, and a sixth structural domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a light chain with a second structural domain, a linker, and a TAA antigen-binding fragment with a fourth structural domain from its N-terminus to its C-terminus; and the fifth polypeptide includes a light chain with a fourth structural domain from its N-terminus to its C-terminus; wherein the first polypeptide and the fifth polypeptide may or may not be present.

359. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus; the third polypeptide includes a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a fourth domain TAA antigen-binding fragment, a linker, and a second domain light chain linker from its N-terminus to its C-terminus; the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fifth polypeptide may or may not be present.

360. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes a fifth structural domain, a linker, and a heavy chain with the first structural domain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a heavy chain with a second structural domain from its N-terminus to its C-terminus; the fourth polypeptide includes a light chain with a second structural domain from its N-terminus to its C-terminus; wherein the first polypeptide and the fourth polypeptide may or may not be present.

361. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, and a light chain of the first structural domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first structural domain; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain of the second structural domain; wherein the fourth polypeptide may or may not be present.

362. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes, from its N-terminus to its C-terminus, a fifth domain, a linker, a first domain heavy chain CD3 antigen-binding fragment, a linker, and a fourth domain heavy chain, wherein the linker may be absent; the third polypeptide includes a second domain heavy chain from its N-terminus to its C-terminus; the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; and the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide, the fourth polypeptide, and the fifth polypeptide may or may not be present.

363. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, and a light chain of the first structural domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first structural domain, a CD3 antigen-binding fragment, a linker, and a heavy chain of the fourth structural domain; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain of the second structural domain; and the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth structural domain; wherein the fourth and fifth polypeptides may or may not be present.

364. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide, from its N-terminus to its C-terminus, sequentially comprises a light chain with a first structural domain, a linker, and a heavy chain with a fourth structural domain; the second polypeptide, from its N-terminus to its C-terminus, sequentially comprises a fifth structural domain, a linker, and a heavy chain with a first structural domain. The linker may be absent; the third polypeptide includes a heavy chain with a second structural domain from the N-terminus to the C-terminus; the fourth polypeptide includes a light chain with a second structural domain from the N-terminus to the C-terminus; the fifth polypeptide includes a light chain with a fourth structural domain from the N-terminus to the C-terminus; wherein, the fourth polypeptide and the fifth polypeptide may be present or absent.

365. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, a light chain of the first structural domain, a linker, and a heavy chain of the fourth structural domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first structural domain, wherein the linker may be absent; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain of the second structural domain; and the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth structural domain; wherein the fourth and fifth polypeptides may or may not be present.

366. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes a fifth structural domain, a linker, and a heavy chain with the first structural domain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a fourth structural domain (TAA antigen-binding fragment), a linker, and a heavy chain with the second structural domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a light chain with the second structural domain from its N-terminus to its C-terminus; and the fifth polypeptide includes a light chain with the fourth structural domain from its N-terminus to its C-terminus; wherein the first polypeptide, the fourth polypeptide, and the fifth polypeptide may or may not be present.

367. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, and a light chain of the first structural domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first structural domain; the third polypeptide comprises, from N-terminus to C-terminus, a fourth structural domain (TAA antigen-binding fragment), a linker, and a heavy chain of the second structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain of the second structural domain; and the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth structural domain; wherein the fourth and fifth polypeptides may or may not be present.

368. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes a fifth structural domain, a linker, and a heavy chain with the first structural domain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a heavy chain with a second structural domain from its N-terminus to its C-terminus; the fourth polypeptide includes a TAA antigen-binding fragment with a fourth structural domain, a linker, and a light chain linker with the second structural domain sequentially from its N-terminus to its C-terminus; the fifth polypeptide includes a light chain with a fourth structural domain from its N-terminus to its C-terminus; wherein the first polypeptide and the fifth polypeptide may or may not be present.

369. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, and a light chain of the first structural domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first structural domain; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a fourth structural domain TAA antigen-binding fragment, a linker, and a light chain linker of the second structural domain; the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth structural domain; wherein the fifth polypeptide may or may not be present.

370. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes a fifth structural domain, a linker, and a heavy chain with the first structural domain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a heavy chain with a second structural domain from its N-terminus to its C-terminus; the fourth polypeptide includes a light chain with a second structural domain, a linker, and a TAA antigen-binding fragment with a fourth structural domain sequentially from its N-terminus to its C-terminus; the fifth polypeptide includes a light chain with a fourth structural domain from its N-terminus to its C-terminus; wherein the first polypeptide and the fifth polypeptide may or may not be present.

371. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, and a light chain of the first structural domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first structural domain; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain of the second structural domain, a linker, and a TAA antigen-binding fragment of the fourth structural domain; the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth structural domain; wherein the fifth polypeptide may or may not be present.

372. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes, from its N-terminus to its C-terminus, a fifth structural domain, a linker, a heavy chain with the first structural domain, a linker, and a third structural domain, wherein the linker may be absent; the third polypeptide includes, from its N-terminus to its C-terminus, a heavy chain with the second structural domain, a linker, and a sixth structural domain; the fourth polypeptide includes a light chain with the second structural domain from its N-terminus to its C-terminus; wherein the first polypeptide and the fourth polypeptide may or may not be present.

373. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, and a light chain of the first structural domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first structural domain, a linker, and a third structural domain; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second structural domain, a linker, and a sixth structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain of the second structural domain; wherein the fourth polypeptide may or may not be present.

374. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes, from its N-terminus to its C-terminus, a fifth domain, a linker, a first domain heavy chain CD3 antigen-binding fragment, a linker, a fourth domain heavy chain, a linker, and a third domain, wherein the linker may be absent; the third polypeptide includes, from its N-terminus to its C-terminus, a second domain heavy chain, a linker, and a sixth domain; the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide, the fourth polypeptide, and the fifth polypeptide may or may not be present.

375. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, and a light chain of the first structural domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first structural domain, a CD3 antigen-binding fragment, a linker, a heavy chain of the fourth structural domain, a linker, and a third structural domain; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second structural domain, a linker, and a sixth structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain of the second structural domain; and the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth structural domain; wherein the fourth and fifth polypeptides may or may not be present.

376. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a first structural domain light chain, a linker, and a fourth structural domain heavy chain; the second polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, a first structural domain heavy chain, a linker, and a third structural domain, wherein the linker may be absent; the third polypeptide comprises, from N-terminus to C-terminus, a second structural domain heavy chain, a linker, and a sixth structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a second structural domain light chain; the fifth polypeptide comprises, from N-terminus to C-terminus, a fourth structural domain light chain; wherein the fourth and fifth polypeptides may or may not be present.

377. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide, from its N-terminus to its C-terminus, sequentially comprises a fifth structural domain, a linker, a light chain of the first structural domain, a linker, and a heavy chain of the fourth structural domain, wherein the linker may be absent; the second polypeptide, from its N-terminus to its C-terminus, sequentially comprises a heavy chain of the first structural domain, a linker, and a third structural domain; the third polypeptide, from its N-terminus to its C-terminus, sequentially comprises a heavy chain of the second structural domain, a linker, and a sixth structural domain; the fourth polypeptide, from its N-terminus to its C-terminus, comprises a light chain of the second structural domain; the fifth polypeptide, from its N-terminus to its C-terminus, comprises a light chain of the fourth structural domain; wherein the fourth and fifth polypeptides may or may not be present.

378. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fifth domain, a linker, a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a fourth domain TAA antigen-binding fragment, a linker, a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a second domain light chain from its N-terminus to its C-terminus; the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide, the fourth polypeptide, and the fifth polypeptide may or may not be present.

379. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, and a light chain of the first structural domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first structural domain, a linker, and a third structural domain, wherein the linker may be absent; the third polypeptide comprises, from N-terminus to C-terminus, a fourth structural domain (TAA antigen-binding fragment), a linker, a heavy chain of the second structural domain, a linker, and a sixth structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain of the second structural domain; the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth structural domain; wherein the fourth and fifth polypeptides may or may not be present.

380. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a light chain with a first structural domain from its N-terminus to its C-terminus; the second polypeptide includes, from its N-terminus to its C-terminus, a fifth structural domain, a linker, a heavy chain with the first structural domain, a linker, and a third structural domain, wherein the linker may or may not be present; the third polypeptide includes, from its N-terminus to its C-terminus, a heavy chain with the second structural domain, a linker, and a sixth structural domain; the fourth polypeptide includes, from its N-terminus to its C-terminus, a light chain with the second structural domain, a linker, and a TAA antigen-binding fragment with the fourth structural domain; the fifth polypeptide includes, from its N-terminus to its C-terminus, a light chain with the fourth structural domain; wherein the first polypeptide and the fifth polypeptide may or may not be present.

381. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, and a light chain of the first structural domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first structural domain, a linker, and a third structural domain; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second structural domain, a linker, and a sixth structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a light chain of the second structural domain, a linker, and a TAA antigen-binding fragment of the fourth structural domain; the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth structural domain; wherein the fifth polypeptide may or may not be present.

382. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide includes a first domain light chain from its N-terminus to its C-terminus; the second polypeptide includes a fifth domain, a linker, a first domain heavy chain, a linker, and a third domain sequentially from its N-terminus to its C-terminus, wherein the linker may be absent; the third polypeptide includes a second domain heavy chain, a linker, and a sixth domain sequentially from its N-terminus to its C-terminus; the fourth polypeptide includes a fourth domain TAA antigen-binding fragment, a linker, and a second domain light chain linker from its N-terminus to its C-terminus; the fifth polypeptide includes a fourth domain light chain from its N-terminus to its C-terminus; wherein the first polypeptide and the fifth polypeptide may or may not be present.

383. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, and a light chain of the first structural domain, wherein the linker may be absent; the second polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the first structural domain, a linker, and a third structural domain, wherein the linker may be absent; the third polypeptide comprises, from N-terminus to C-terminus, a heavy chain of the second structural domain, a linker, and a sixth structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a fourth structural domain TAA antigen-binding fragment, a linker, and a light chain linker of the second structural domain; the fifth polypeptide comprises, from N-terminus to C-terminus, a light chain of the fourth structural domain; wherein the fifth polypeptide may or may not be present.

384. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, and / or a fourth polypeptide, and / or a fifth polypeptide, wherein, The first polypeptide comprises, from N-terminus to C-terminus, a first structural domain light chain, a linker, and a fourth structural domain heavy chain; the second polypeptide comprises, from N-terminus to C-terminus, a fifth structural domain, a linker, a first structural domain heavy chain, a linker, and a third structural domain, wherein the linker may be absent; the third polypeptide comprises, from N-terminus to C-terminus, a second structural domain heavy chain, a linker, and a sixth structural domain; the fourth polypeptide comprises, from N-terminus to C-terminus, a second structural domain light chain; the fifth polypeptide comprises, from N-terminus to C-terminus, a fourth structural domain light chain; wherein the fourth and fifth polypeptides may or may not be present.

385. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 46, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

386. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 167, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 177, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

387. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 77, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

388. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 167, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 190, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

389. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3227, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 46, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

390. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3232, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 177, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

391. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3230, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 46, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

392. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3231, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 46, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

393. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 62, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

394. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3225, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3222, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

395. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3226, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3223, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

396. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3225, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3216, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

397. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3226, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3217, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

398. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3227, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 77, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

399. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3228, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 77, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

400. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3229, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 77, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

401. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3230, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 77, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

402. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3231, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 77, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

403. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3233, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3216, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

404. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3234, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3217, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

405. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3235, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 177, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

406. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3236, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 177, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

407. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3237, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 177, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

408. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3238, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 177, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

409. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3232, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 190, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

410. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3232, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 184, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

411. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1007, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1005, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

412. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1020, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1008, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1006, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

413. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1005, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

414. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3232, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1006, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

415. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1018, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

416. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 3232, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 1019, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

417. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2000, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

418. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 167, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2015, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

419. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 342, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2016, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

420. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 168, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2017, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

421. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2021, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2000, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

422. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2024, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2000, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

423. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2027, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2000, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

424. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2022, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2000, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

425. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2023, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2000, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

426. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2030, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2015, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

427. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2010, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

428. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 167, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2018, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

429. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2030, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 2018, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

430. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 21, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO: 46, wherein the second polypeptide and the third polypeptide are linked by disulfide bonds in the heavy chain Fc structure or form a heterodimer (e.g., by pestle-mortar pairing in the heavy chain Fc domain).

431. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 440, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

432. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 443, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

433. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 444, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

434. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 445, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

435. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 446, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

436. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 447, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

437. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 448, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

438. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 449, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

439. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 450, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

440. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 451, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

441. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 452, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

442. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 453, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

443. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 454, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

444. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 455, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

445. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 456, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

446. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 457, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

447. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 458, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

448. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 459, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

449. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 460, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

450. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 461, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

451. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 462, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

452. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 463, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

453. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 464, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

454. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 465, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

455. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 466, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

456. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 467, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

457. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 468, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

458. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 469, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

459. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 470, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

460. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 471, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

461. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 472, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

462. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 473, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

463. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 474, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

464. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 475, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

465. The fusion polypeptide according to any one of claims 1-348, comprising a first polypeptide, and / or a second polypeptide, and / or a third polypeptide, wherein, The first polypeptide comprises the amino acid sequence shown in SEQ ID NO: 11, the second polypeptide comprises the amino acid sequence shown in SEQ ID NO: 476, and the third polypeptide comprises the amino acid sequence shown in SEQ ID NO:

46.

466. The fusion polypeptide as claimed in any of the preceding claims, wherein, The indirect connection includes connections via connector sub-connections.

467. The fusion polypeptide as claimed in any of the preceding claims, wherein, The linker comprises an amino acid sequence selected from the group consisting of: SS, GS, GGS, GSGS, SEQ ID NO: 5 to SEQ ID NO:

10.

468. An immunoconjugate comprising the fusion polypeptide of any one of claims 1-467.

469. A nucleic acid molecule encoding a fusion polypeptide as described in any one of claims 1-467.

470. A carrier comprising the nucleic acid molecule of claim 469.

471. A cell comprising and / or expressing the fusion polypeptide of any one of claims 1-467, the immunoconjugate of claim 468, the nucleic acid molecule of claim 469, and / or the vector of claim 470.

472. A composition comprising a fusion polypeptide of any one of claims 1-467, an immunoconjugate of claim 468, a nucleic acid molecule of claim 469, and / or a carrier of claim 470, and / or a cell of claim 471, and optionally a pharmaceutically acceptable carrier.

473. A method for preparing a fusion polypeptide according to any one of claims 1-467, comprising culturing cells according to claim 471 under conditions that enable the fusion polypeptide to be expressed.

474. A method for inhibiting the growth and / or proliferation of tumors or tumor cells, comprising administering an effective amount of any of the fusion polypeptides of claims 1-467, the immunoconjugate of claim 468, the nucleic acid molecule of claim 469, and / or the carrier of claim 470, the cell of claim 471, and / or the composition of claim 472.

475. Use of the fusion polypeptide of any one of claims 1-467, the immunoconjugate of claim 468, the nucleic acid molecule of claim 469, and / or the carrier of claim 470, the cell of claim 471, and / or the composition of claim 472 in the preparation of a medicament, wherein the medicament is used for the prevention, improvement and / or treatment of tumors.

476. The use according to claim 475, wherein the tumor comprises a solid tumor and / or a hematoma.

477. The use according to any one of claims 475, wherein the tumor is selected from the group consisting of: colon tumors, breast tumors, lung tumors, gastric tumors, melanoma, head and neck tumors, lymphoma, nasopharyngeal tumors, cervical tumors, esophageal tumors, kidney tumors, squamous cell carcinoma of the skin, endometrial tumors, liver tumors, bladder tumors, urothelial tumors, and skin tumors.

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