Anti-B7-H7 antibody or its antigen-binding fragment, manufacturing method, and application

Abstract

The present invention discloses an anti-B7-H7 antibody or an antigen-binding fragment thereof, and a method for producing and applying the same, the antibody comprising a VL and / or a VH, the VL comprising CDRs LCDR1, LCDR2 and LCDR3 shown in the amino acid sequences of SEQ ID NO:82, SEQ ID NO:94-100, SEQ ID NO:111, 112, 114-116, 120 and 121 or mutations thereof, and the VH comprising CDRs HCDR1, HCDR2 and HCDR3 shown in the amino acid sequences of SEQ ID NO:7, SEQ ID NO:34 or 36, SEQ ID NO:57-68 or mutations thereof. The anti-B7-H7 antibody or its antigen-binding fragment described in the present invention has high affinity and high biological activity for B7-H7, can effectively block the binding of B7-H7 to its receptor CD28H and the binding of B7-H7 to its receptor KIR3DL3, and it specifically binds only to B7-H7, does not cross-react with other member proteins of the B7 family, has excellent stability, and yet exhibits high in vivo anti-tumor activity.

Description

[Technical Field]

[0001] This international patent application claims priority to Chinese Patent Application No. 202210071861.3, filed on 21 January 2022, the contents of which are incorporated herein by reference in their entirety.

[0002] This invention relates to the field of biopharmaceuticals, and more particularly to anti-B7-H7 antibodies or their antigen-binding fragments, as well as methods for producing the same and their applications. [Background technology]

[0003] In the tumor microenvironment, immune checkpoint molecules are often highly expressed, promoting the attack of the tumor-evading immune system by inhibiting T cell activation and inducing T cell depletion. Immune checkpoint inhibition is the most advanced therapeutic approach in current anti-tumor immunotherapy, yielding the best therapeutic effects. For example, anti-PD1, PD-L1, and CTLA-4 immune checkpoint inhibitors have shown clinically potent antitumor activity. Therefore, the 2018 Nobel Prize in Physiology or Medicine honored two scientists who discovered negative immune regulation of PD1 and CTLA-4, making a significant contribution to cancer treatment.

[0004] Clinically, treatment with anti-PD1, PD-L1, and CTLA-4 antibodies has shown good therapeutic effects, but the patient response rate is not high, and the majority of patients are resistant to treatment with these targets or show only moderate therapeutic effects. The tumor microenvironment has proven to be a very complex and comprehensive mechanism, with multiple immunosuppressive molecules, suppressor cells, and specific tumor tissue structures working together to block the development of a normal immune response, making it difficult to achieve good therapeutic effects by simply blocking an immune checkpoint. In addition to these PD1, PD-L1, and CTLA-4 targets, other immune checkpoints, such as Tim3, Lag3, and TIGIT, are also highly expressed in the tumor microenvironment. Current research on these immune checkpoints suggests that inhibiting these targets or combining them with anti-PD1 / PD-L1 antibodies can further enhance the therapeutic effect against tumors.

[0005] The B7 family is an important family of immune system co-stimulatory / inhibitory molecules, and currently comprises 10 molecules: CD80 (B7.1), CD86 (B7.2), B7H1 (PD-L1 / CD274), B7-DC (PD-L2 / CD273), B7H2 (ICOSL), B7H3 (CD276), B7H4 (B7S1 / B7x / Vtcn1), B7H5 (VISTA), B7H6, and B7-H7 (HHLA2). Several members of the B7 family, or their receptors, such as PD-L1 / PD1, CTLA4, B7H4, and VISTA, have been proven to be immune checkpoints.

[0006] B7-H7 is currently the newest molecule in the B7 family and, unlike other molecules in the family, possesses three extracellular Ig domains. The in vitro function of B7-H7 is somewhat controversial and may be related to the different receptors it acts on. One of these receptors is CD28H, and it has been reported that B7-H7 can act on CD28H to promote the function of T cells or NK cells (Nat Commun. 2013;4:2043; Cancer Immunol Res. 2019;7(6):939-951.), while another report suggests that B7-H7 can inhibit T cell function by acting on KIR3DL3 (Cancer Immunol Res. 2020 Nov 23;canimm.0315.2020.).

[0007] In normal tissues, B7-H7 is highly expressed primarily in tissues such as the gastrointestinal tract and bile ducts. Patient sample studies have found that the B7-H7 molecule is highly expressed in many tumor types, including breast cancer, lung cancer, colon cancer, and pancreatic cancer, and that its expression level tends to show a negative correlation with prognosis and survival rate (Clin Cancer Res. 2015 May 15;21(10):2359-2366; Onco Targets Ther. 2018;11:1563-1570). Therefore, in the body, B7-H7 functions as an immune checkpoint, inhibiting the immune response. Blocking the action of B7-H7 and reactivating the immune system by producing neutralizing antibodies is a promising therapeutic approach for tumors with high B7-H7 expression.

[0008] Currently, research on B7-H7 is limited, or all studies are still in preclinical development. Therefore, there is a strong need for the development of human-derived anti-B7-H7 antibodies that exhibit high affinity, high biological activity, and high in vivo antitumor activity. [Overview of the project]

[0009] The technical problem that this invention aims to solve is to provide an anti-B7-H7 antibody or its antigen-binding fragment, as well as a method for producing the same and its applications, in order to overcome the shortage of anti-B7-H7 antibodies in the prior art.

[0010] To solve the above technical problems, a first aspect of the present invention provides an anti-B7-H7 antibody or its antigen-binding fragment, wherein the anti-B7-H7 antibody or its antigen-binding fragment comprises a light chain variable region (VL) and / or a heavy chain variable region (VH), where, The VL includes a complementarity-determining region (CDR) or a mutation thereof, which is LCDR1 shown in the amino acid sequence of SEQ ID NO:82, LCDR2 shown in any one amino acid sequence of SEQ ID NO:94-100, and / or LCDR3 shown in any one amino acid sequence of SEQ ID NO:111, 112, 114-116, 120, and 121. The VH contains a CDR such as HCDR1 shown by the amino acid sequence of SEQ ID NO:7, HCDR2 shown by the amino acid sequence of SEQ ID NO:34 or 36, and / or HCDR3 shown by any one of the amino acid sequences of SEQ ID NOs:57 - 68, or a mutation thereof. Here, the mutation has an insertion, deletion or substitution of 3, 2 or 1 amino acids in the amino acid sequence of the CDR.

[0011] In this application, in a similar "having an insertion, deletion or substitution of 3, 2 or 1 amino acids", the "amino acid mutation" refers to the presence of an amino acid mutation in the mutant sequence compared to the original amino acid sequence, including those where an insertion, deletion or substitution of an amino acid has occurred in the original amino acid sequence. As an exemplary interpretation, the mutation to the CDR may include mutations of 3, 2 or 1 amino acids, and for these CDRs, any optional and same or different number of amino acid residues may be selected for mutation. For example, one amino acid in CDR1 may be mutated and the amino acids in CDR2 and CDR3 may not be mutated.

[0012] In this application, the mutation may currently include mutations known to those skilled in the art. For example, in the process of producing or using an antibody, several mutations may be made to the antibody. For example, mutations may be made to potential post-translational modification (PTMs) sites, especially in the CDR region, including related mutations such as antibody aggregation, asparagine deamidation susceptibility (sites such as NG, NS, NH, etc.), aspartic acid isomerization (DG, DP) susceptibility sites, N-glycosylation (N-{P}S / T) susceptibility sites and oxidation susceptibility sites.

[0013] Preferably, the mutation of LCDR1 has 3, 2 or 1 amino acid substitutions of S5G, I6V / F, S7N, S8N / Y, W9N / Y and L10F in the amino acid sequence shown in SEQ ID NO:82, and the mutant amino acid sequence of the LCDR1 is preferably as shown in any one of SEQ ID NO:81, 83-88.

[0014] Preferably, the mutation of LCDR3 has 1 amino acid substitution of N4Q, S5A and Y8V in the amino acid sequence shown in SEQ ID NO:112, or the mutation of LCDR3 has 2 or 1 amino acid substitutions of Q1H, N4Y, N5I / K and L8Y in the amino acid sequence shown in SEQ ID NO:115, or the mutation of LCDR3 has 1 amino acid substitution of N4Q and S5A in the amino acid sequence shown in SEQ ID NO:116, and the mutant amino acid sequence of the LCDR3 is preferably as shown in any one of SEQ ID NO:113, 117-119, 122-125.

[0015] Preferably, the mutation of HCDR1 has 2 or 1 amino acid substitutions of F2G and D6R / N / S / Y / T in the amino acid sequence shown in SEQ ID NO:7, and the mutant amino acid sequence of the HCDR1 is preferably as shown in any one of SEQ ID NO:8-13.

[0016] Preferably, the mutation of HCDR2 has 2 or 1 amino acid substitutions of Y2F, D3N / E, G4E / A, S5N / T / R and N6E / D / K in the amino acid sequence shown in SEQ ID NO:36, and the mutant amino acid sequence of the HCDR2 is preferably as shown in any one of SEQ ID NO:27-33, 35, 37-40.

[0017] The S5G described above generally refers to a mutation in which the amino acid S at position 5 of the amino acid sequence shown in SEQ ID NO:82 is changed to G. Other amino acid substitutions, such as I6V / F, S7N, S8N / Y, W9N / Y, and L10F, are similar and their meaning should be understandable to those skilled in the art.

[0018] Preferably, the amino acid sequence of LCDR1 is as shown in SEQ ID NO:87, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:97, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:120, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:82, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:94, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:112, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:82, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:94, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:122, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:82, and the amino acid sequence of LCDR2 is as shown in SEQ ID As shown in NO:94, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:123, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:85, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:97, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:116, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:85, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:97, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:124, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:85, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:97, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:125, or the amino acid sequence of LCDR1 is SEQ ID As shown in NO:81, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:94, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:111, or the amino acid sequence of LCDR1 is as shown in SEQ IDAs shown in NO:82, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:94, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:111, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:82, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:94, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:117, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:82, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:96, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:114, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:83, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:95, and the amino acid sequence of LCDR3 is as shown in SEQ ID As shown in NO:113, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:83, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:98, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:113, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:83, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:99, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:119, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:84, the amino acid sequence of LCDR2 is as shown in SEQ ID NO:95, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:115, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:86, and the amino acid sequence of LCDR2 is SEQ ID As shown in NO:95, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:118, or the amino acid sequence of LCDR1 is as shown in SEQ ID NO:88, and the amino acid sequence of LCDR2 is as shown in SEQ IDAs shown in NO:100, and the amino acid sequence of LCDR3 is as shown in SEQ ID NO:121.

[0019] Preferably, the amino acid sequence of HCDR1 is as shown in SEQ ID NO:12, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:34, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:66, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:7, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:28, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:58, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:7, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:37, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:58, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:7, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:38, and the amino acid sequence of HCDR3 is as shown in SEQ ID As shown in NO:58, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:9, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:27, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:63, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:9, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:39, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:63, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:9, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:40, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:63, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:7, and the amino acid sequence of HCDR2 is SEQ ID As shown in NO:27, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:57, or the amino acid sequence of HCDR1 is as shown in SEQ IDAs shown in NO:7, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:28, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:59, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:7, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:36, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:68, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:8, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:29, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:60, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:8, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:30, and the amino acid sequence of HCDR3 is as shown in SEQ ID As shown in NO:62, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:8, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:32, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:62, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:9, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:27, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:61, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:9, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:31, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:64, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:10, and the amino acid sequence of HCDR2 is SEQ ID As shown in NO:29, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:62, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:11, and the amino acid sequence of HCDR2 is as shown in SEQ IDAs shown in NO:33, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:65, or the amino acid sequence of HCDR1 is as shown in SEQ ID NO:13, the amino acid sequence of HCDR2 is as shown in SEQ ID NO:35, and the amino acid sequence of HCDR3 is as shown in SEQ ID NO:67. In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 87, 97, and 120, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 12, 34, and 66, respectively.

[0020] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 94, and 112, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 7, 28, and 58, respectively.

[0021] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 94, and 112, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 7, 37, and 58, respectively.

[0022] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 94, and 122, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 7, 37, and 58, respectively.

[0023] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 94, and 123, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 7, 37, and 58, respectively.

[0024] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 94, and 112, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 7, 38, and 58, respectively.

[0025] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 94, and 122, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 7, 38, and 58, respectively.

[0026] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 94, and 123, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 7, 38, and 58, respectively.

[0027] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 94, and 122, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 7, 28, and 58, respectively.

[0028] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 94, and 123, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 7, 28, and 58, respectively.

[0029] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 85, 97, and 116, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 9, 27, and 63, respectively.

[0030] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 85, 97, and 116, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 9, 39, and 63, respectively.

[0031] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 85, 97, and 124, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 9, 39, and 63, respectively.

[0032] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 85, 97, and 125, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 9, 39, and 63, respectively.

[0033] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 85, 97, and 116, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 9, 40, and 63, respectively.

[0034] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 85, 97, and 124, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 9, 40, and 63, respectively.

[0035] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 85, 97, and 125, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 9, 40, and 63, respectively.

[0036] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 85, 97, and 124, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 9, 27, and 63, respectively.

[0037] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 85, 97, and 125, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 9, 27, and 63, respectively.

[0038] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 81, 94, and 111, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 7, 27, and 57, respectively.

[0039] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 94, and 112, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 7, 28, and 59, respectively.

[0040] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 83, 95, and 113, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 8, 29, and 60, respectively.

[0041] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 96, and 114, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 9, 27, and 61, respectively.

[0042] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 84, 95, and 115, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 10, 29, and 62, respectively.

[0043] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 83, 98, and 113, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 8, 30, and 62, respectively.

[0044] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 94, and 117, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 9, 31, and 64, respectively.

[0045] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 86, 95, and 118, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 8, 32, and 62, respectively.

[0046] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 83, 99, and 119, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 11, 33, and 65, respectively.

[0047] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 88, 100, and 121, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 13, 35, and 67, respectively.

[0048] In one preferred embodiment, the amino acid sequences of LCDR1, LCDR2, and LCDR3 contained in the VL of the anti-B7-H7 antibody or its antigen-binding fragment are as shown in SEQ ID NO: 82, 94, and 111, respectively, and the amino acid sequences of HCDR1, HCDR2, and HCDR3 contained in the VH are as shown in SEQ ID NO: 7, 36, and 68, respectively.

[0049] In this invention, the amino acid sequences of the CDRs listed above are all shown according to the Chothia definition rules. However, as those skilled in the art will know, in the art, the CDRs of antibodies can be defined in various ways, for example, by the Kabat definition rules based on sequence variability (see Kabat et al., Immunological Protein Sequences, Fifth Edition, National Institutes of Health, Bethesda, Maryland (1991)) and by the Chothia definition rules based on the position of the structural loop region (see JMol Biol 273:927-48, 1997). In the technical proposal of this invention, amino acid residues in the variable domain sequence can also be determined using a Combined definition rule that includes both the Kabat and Chothia definitions. Here, the Combined definition rule combines the ranges of the Kabat and Chothia definitions to obtain a larger range, for details, see Table 1-6 in the Examples section. As those skilled in the art will understand, unless otherwise specified, the terms “CDR” and “complementarity-determining region” for a given antibody or region thereof (e.g., variable region) should be understood to cover the complementarity-determining region as defined by any one of the known schemes described in the present invention. While the scope claimed in the present invention is a sequence shown according to the Chothia definition rule, corresponding amino acid sequences according to other CDR definition rules also fall within the scope of protection of the present invention.

[0050] Preferably, the light chain variable region (VL) further comprises a light chain variable region framework region (VL FWR), the VL FWR being a light chain variable region framework region of a human antibody, and the gene encoding the VL FWR is preferably derived from the germline V gene IGKV1-5*03, IGKV3-15*01, IGKV1-27*01, or IGKV1-9*01. More preferably, the VL FWR comprises VL FWR1 whose amino acid sequence is represented by one of SEQ ID NO: 74~79 or a mutant sequence thereof, VL FWR2 whose amino acid sequence is represented by one of SEQ ID NO: 90~92 or a mutant sequence thereof, VL FWR3 whose amino acid sequence is represented by one of SEQ ID NO: 102~109 or a mutant sequence thereof, and VL FWR4 whose amino acid sequence is represented by one of SEQ ID NO: 127~130 or a mutant sequence thereof. Here, the mutations described above involve 3, 2, or 1 amino acid insertions, deletions, substitutions, and duplications in the amino acid sequence of the VL FWR.

[0051] Preferably, the heavy chain variable region (VH) further comprises a heavy chain variable region framework region (VH FWR), the VH FWR being a heavy chain variable region framework region of a human antibody, and the gene encoding the VH FWR is preferably derived from the germline V gene IGHV3-33*01, IGHV3-33*06, or IGHV1-69*01. More preferably, the VH FWR comprises VH FWR1 whose amino acid sequence is represented by one of SEQ ID NO: 2~5 or a mutant sequence thereof, VH FWR2 whose amino acid sequence is represented by one of SEQ ID NO: 15~25 or a mutant sequence thereof, VH FWR3 whose amino acid sequence is represented by one of SEQ ID NO: 42~55 or a mutant sequence thereof, and VH FWR4 whose amino acid sequence is represented by one of SEQ ID NO: 70~72 or a mutant sequence thereof. Here, the mutations described above have 3, 2, or 1 amino acid insertions, deletions, substitutions, and duplications in the amino acid sequence of the VH FWR.

[0052] In one embodiment of the present invention, VL comprises an amino acid sequence represented by any one of SEQ ID NO: 151 to 167 or a mutation thereof. In one embodiment of the present invention, VH comprises an amino acid sequence represented by any one of SEQ ID NO: 132 to 149 or a mutation thereof.

[0053] In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 161, and VH includes the amino acid sequence shown in SEQ ID NO: 143. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 152, and VH includes the amino acid sequence shown in SEQ ID NO: 133. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 152, and VH includes the amino acid sequence shown in SEQ ID NO: 146. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 164, and VH includes the amino acid sequence shown in SEQ ID NO: 146. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 165, and VH includes the amino acid sequence shown in SEQ ID NO: 146. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 152, and VH includes the amino acid sequence shown in SEQ ID NO: 147. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 164, and VH includes the amino acid sequence shown in SEQ ID NO: 147. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 165, and VH includes the amino acid sequence shown in SEQ ID NO: 147. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 164, and VH includes the amino acid sequence shown in SEQ ID NO: 133. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 165, and VH includes the amino acid sequence shown in SEQ ID NO: 133. In one preferred embodiment, VL comprises the amino acid sequence shown in SEQ ID NO:156, and VH comprises the amino acid sequence shown in SEQ ID NO:138.In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 156, and VH includes the amino acid sequence shown in SEQ ID NO: 148. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 166, and VH includes the amino acid sequence shown in SEQ ID NO: 148. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 167, and VH includes the amino acid sequence shown in SEQ ID NO: 148. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 156, and VH includes the amino acid sequence shown in SEQ ID NO: 149. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 166, and VH includes the amino acid sequence shown in SEQ ID NO: 149. In one preferred embodiment, the VL includes the amino acid sequence shown in SEQ ID NO: 167, and the VH includes the amino acid sequence shown in SEQ ID NO: 149. In one preferred embodiment, the VL includes the amino acid sequence shown in SEQ ID NO: 166, and the VH includes the amino acid sequence shown in SEQ ID NO: 138. In one preferred embodiment, the VL includes the amino acid sequence shown in SEQ ID NO: 167, and the VH includes the amino acid sequence shown in SEQ ID NO: 138. In one preferred embodiment, the VL includes the amino acid sequence shown in SEQ ID NO: 151, and the VH includes the amino acid sequence shown in SEQ ID NO: 132. In one preferred embodiment, the VL includes the amino acid sequence shown in SEQ ID NO: 152, and the VH includes the amino acid sequence shown in SEQ ID NO: 134. In one preferred embodiment, VL comprises the amino acid sequence shown in SEQ ID NO:153, and VH comprises the amino acid sequence shown in SEQ ID NO:135.In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 154, and VH includes the amino acid sequence shown in SEQ ID NO: 136. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 155, and VH includes the amino acid sequence shown in SEQ ID NO: 137. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 157, and VH includes the amino acid sequence shown in SEQ ID NO: 139. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 158, and VH includes the amino acid sequence shown in SEQ ID NO: 140. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 159, and VH includes the amino acid sequence shown in SEQ ID NO: 141. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 160, and VH includes the amino acid sequence shown in SEQ ID NO: 142. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 162, and VH includes the amino acid sequence shown in SEQ ID NO: 144. In one preferred embodiment, VL includes the amino acid sequence shown in SEQ ID NO: 163, and VH includes the amino acid sequence shown in SEQ ID NO: 145. The above mutation results in the deletion, substitution, or addition of one or more amino acid residues in the amino acid sequence of VH and / or VL, and the amino acid sequence of the mutation has at least 85% sequence identity with the amino acid sequence of VH and / or VL, maintaining or improving the binding of the antibody to B7-H7, and the at least 85% sequence identity is preferably at least 90%, more preferably at least 95%, 96%, 97%, or 98%, and most preferably at least 99%.

[0054] Preferably, the anti-B7-H7 antibody or its antigen-binding fragment described in the present invention may be a full-length antibody, Fab, Fab', F(ab')2, Fv, preferably scFv, a bispecific antibody, a multispecific antibody, a heavy chain antibody, or a single-domain antibody, or a monoclonal antibody or polyclonal antibody produced from the above antibodies.

[0055] In this application, the "Fab fragment" consists of a light chain and a heavy chain with CH1 and a variable region. The heavy chain of the Fab molecule cannot form a disulfide bond with another heavy chain molecule. The "Fc" region contains two heavy chain fragments containing the CH1 and CH2 domains of the antibody. The two heavy chain fragments consist of two or more disulfide bonds and are held together by the hydrophobicity of the CH3 domain. The "Fab fragment" contains a light chain and a portion of a heavy chain containing a VH domain, a CH1 domain, and a region between the CH1 and CH2 domains, thereby forming an interchain disulfide bond between the two heavy chains of the two Fab' fragments to form an F(ab')2 molecule. The "F(ab')2 fragment" contains two light chains and two heavy chains containing a portion of the constant region between the CH1 and CH2 domains, thereby forming an interchain disulfide bond between the two heavy chains. Therefore, the F(ab')2 fragment consists of two Fab' fragments held together via a disulfide bond between the two heavy chains. The term "Fv" refers to an antibody fragment consisting of the VL and VH domains of a single arm of the antibody, but lacking a constant region.

[0056] In this application, the scFv (single-chain antibody fragment) may be a conventional single-chain antibody of the art, comprising a heavy-chain variable region, a light-chain variable region, and a short peptide of 15 to 20 amino acids. Here, the VL and VH domains pair via a linker that enables them to be generated as a single polypeptide chain to form a monovalent molecule [see, for example, Bird et al., Science 242:423-426 (1988) and Huston et al., Proc. Natl. Acad. Sci. USA 85:5879-5883 (1988)]. Such an scFv molecule may have the common structure NH2-VL-linker-VH-COOH or NH2-VH-linker-VL-COOH. A suitable prior art linker consists of a duplicated G4S amino acid sequence or a variant thereof. For example, a linker having the amino acid sequence (G4S)4 or (G4S)3 may be used, or a variant thereof may be used.

[0057] In this application, the term “multispecific antibody” is used in its broadest sense and covers antibodies having specificity to multiple epitopes. These multispecific antibodies include antibodies comprising a heavy chain variable region (VH) and a light chain variable region (VL), wherein the VH-VL unit comprises an antibody having specificity to multiple epitopes, and an antibody having two or more VL and VH regions, where each VH-VL unit comprises an antibody that binds to a different target or a different epitope of the same target, and an antibody having two or more single variable regions, where each single variable region binds to a different target or a different epitope of the same target, and include, but are not limited to, full-length antibodies, antibody fragments, diabodies, triabodies, and antibody fragments covalently or noncovalently linked together.

[0058] In this application, the monoclonal antibody, mAb, or Ab refers to an antibody obtained from a single clonal cell line, and the cell line is not limited to eukaryotic, prokaryotic, or phage clonal cell lines.

[0059] In this application, the term "heavy chain antibody" refers to an antibody containing only one heavy chain variable region (VHH) and two common CH2 and CH3 regions, and is also called HCAbs.

[0060] A "single-domain antibody," also known as a "nano-antibody," refers to a VHH structure cloned from a heavy-chain antibody and is the smallest known unit capable of binding to a target antigen.

[0061] In one embodiment of the present invention, the anti-B7-H7 antibody or its antigen-binding fragment is a full-length antibody comprising an antibody heavy chain constant region and an antibody light chain constant region. Preferably, the heavy chain constant region is selected from hIgG1, hIgG2, hIgG3, or hIgG4, and the light chain constant region is selected from the κ chain or λ chain of a human-derived antibody. More preferably, the heavy chain constant region is hIgG1 and the light chain constant region is the κ chain of a human-derived antibody.

[0062] In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises an amino acid sequence shown in any one of SEQ ID NO: 169-190 or a mutation thereof, and / or the light chain comprises an amino acid sequence shown in any one of SEQ ID NO: 192-208 or a mutation thereof.

[0063] In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 186, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 202. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 180, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 202. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 184, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 193. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 170, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 193. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 187, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 193. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 187, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 205. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 187, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 206. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 188, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 193. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO:188, and the light chain comprises the amino acid sequence shown in SEQ ID NO:205.In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 188, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 206. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 184, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 205. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 184, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 206. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 185, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 197. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 175, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 197. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 189, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 197. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 189, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 207. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 189, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 208. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO:190, and the light chain comprises the amino acid sequence shown in SEQ ID NO:197.In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 190, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 207. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 190, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 208. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 185, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 207. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 185, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 208. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 169, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 192. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 171, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 193. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 172, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 194. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 173, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 195. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO:174, and the light chain comprises the amino acid sequence shown in SEQ ID NO:196.In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 176, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 198. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 177, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 199. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 178, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 200. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 179, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 201. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO:181, and the light chain comprises the amino acid sequence shown in SEQ ID NO:203. In one preferred embodiment, the full-length antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO:182, and the light chain comprises the amino acid sequence shown in SEQ ID NO:204. The above mutation results in the deletion, substitution, or addition of one or more amino acid residues in the amino acid sequences of the heavy chain and / or light chain, and the amino acid sequence of the mutation has at least 85% sequence identity with the amino acid sequences of the heavy chain and / or light chain, maintaining or improving the binding of the antibody to B7-H7, wherein the at least 85% sequence identity is preferably at least 90%, more preferably at least 95%, and most preferably at least 99%.

[0064] To solve the above technical problems, a second aspect of the present invention provides an isolated nucleic acid which encodes an anti-B7-H7 antibody or an antigen-binding fragment thereof as described in the first aspect of the present invention.

[0065] The nucleic acid production method described above is a conventional production method in the art and preferably includes the step of obtaining a nucleic acid molecule encoding the antibody by gene cloning technology, or by an artificial whole sequence synthesis method. As those skilled in the art know, substitutions, deletions, modifications, insertions, or additions may be appropriately introduced into the base sequence of the amino acid sequence encoding the antibody in order to provide a polynucleotide homolog. In the present invention, a polynucleotide homolog can be produced by substituting, deleting, or adding to one or more bases encoding the antibody sequence gene, within a range that maintains antibody activity.

[0066] To solve the above technical problems, a third aspect of the present invention provides a recombinant expression vector, the recombinant expression vector comprising the isolated nucleic acid described in the second aspect of the present invention.

[0067] The recombinant expression vector can be obtained by conventional methods in the art, that is, by ligating the nucleic acid molecule described in this application to various expression vectors. The expression vector is any conventional vector in the art that can accept the nucleic acid molecule. Preferably, the expression vector includes a eukaryotic cell expression vector and / or a prokaryotic cell expression vector.

[0068] To solve the above technical problems, a fourth aspect of the present invention provides a transformant, the transformant comprising a recombinant expression vector described in the third aspect of the present invention.

[0069] The method for producing the transformant may be a conventional method in the art, for example, by transforming a host cell with the recombinant expression vector. The host cell of the transformant may be any of the conventional host cells in the art, as long as it can stably self-replicate the recombinant expression vector and effectively express the nucleic acid it carries. Preferably, the host cell is a prokaryotic cell and / or a eukaryotic cell, the prokaryotic cell is preferably an E. coli cell, for example TG1, BL21 (expressing a single-chain antibody or a Fab antibody), and the eukaryotic cell is preferably a HEK293 cell or a CHO cell (expressing a full-length IgG antibody). By transforming a host cell with the recombinant expression plasmid described above, a preferred recombinant expression transformant of the present invention can be obtained. Here, the transformation method is a conventional transformation method in the art, preferably a chemical transformation method, a heat treatment method, or an electrical transformation method.

[0070] To solve the above technical problems, a fifth aspect of the present invention provides a chimeric antigen receptor, the chimeric antigen receptor comprising the anti-B7-H7 antibody described in the first aspect of the present invention or its antigen-binding fragment.

[0071] To solve the above technical problems, a sixth aspect of the present invention provides a gene-modified cell comprising a chimeric antigen receptor as described in the fifth aspect of the present invention.

[0072] Preferably, the gene-modified cells are eukaryotic cells, preferably isolated human cells, and more preferably immune cells such as T cells or NK cells.

[0073] To solve the above technical problems, a seventh aspect of the present invention provides a method for producing an anti-B7-H7 antibody or its antigen-binding fragment, the production method comprising the steps of culturing the transformant described in the fourth aspect of the present invention and obtaining an anti-B7-H7 antibody or its antigen-binding fragment from the culture.

[0074] To solve the above technical problems, an eighth aspect of the present invention provides an antibody-drug conjugate comprising an antibody portion and a conjugate portion, wherein the antibody portion comprises the anti-B7-H7 antibody described in the first aspect of the present invention or its antigen-binding fragment, and the conjugate portion comprises, but is not limited to, a detectable marker, drug, toxin, cytokine, radionuclide, enzyme, or a combination thereof, and the antibody portion and the conjugate portion can be conjugated, for example, via a chemical bond or a linker.

[0075] To solve the above technical problems, a ninth aspect of the present invention provides a pharmaceutical composition comprising an anti-B7-H7 antibody or its antigen-binding fragment as described in the first aspect of the present invention, a chimeric antigen receptor as described in the fifth aspect of the present invention, genetically modified cells as described in the sixth aspect of the present invention, and / or an antibody-drug conjugate as described in the eighth aspect of the present invention.

[0076] The pharmaceutical composition of the present invention can be manufactured in various dosage forms as needed, and a physician can determine and administer a dose beneficial to the patient based on factors such as the patient's type, age, weight, general state of the disease, and method of administration. Preferably, the pharmaceutical composition is in liquid, gaseous, solid, or semi-solid dosage forms.

[0077] Preferably, the pharmaceutical composition may be administered orally, by injection, intranasally, transdermally, or via mucosal administration.

[0078] Preferably, the pharmaceutical composition further comprises another antitumor antibody as an active ingredient.

[0079] Preferably, the pharmaceutical composition further comprises a pharmaceutically acceptable carrier. More preferably, the pharmaceutical composition comprises 0.01 to 99.99% of the anti-B7-H7 antibody or its antigen-binding fragment, a chimeric antigen receptor, genetically modified cells, an antibody-drug conjugate, and 0.01 to 99.99% of the pharmaceutical carrier, wherein the percentage is a mass percentage relative to the pharmaceutical composition.

[0080] The dosage level of the pharmaceutical composition described in the present invention can be adjusted according to the amount of composition required to achieve the desired diagnostic or therapeutic effect. The administration plan may be a single injection or multiple injections, or may be modified. The selected dosage level and plan are reasonably adjusted according to various factors, including the activity and stability (half-life) of the pharmaceutical composition, formulation, route of administration, combination with other drugs or treatments, the disease or condition to be detected and / or treated, and the health status and treatment history of the subject being treated.

[0081] The therapeutically effective dose of the pharmaceutical composition of the present invention can first be estimated in cell culture experiments or animal models, such as rodents, rabbits, dogs, pigs, and / or primates. Animal models can also be used to determine appropriate dose ranges and routes. These can then be used to determine effective doses and routes for administration to humans. Generally, the determination and adjustment of effective doses or dosages, and the evaluation of when and how to make such adjustments, are known to those skilled in the art.

[0082] For further guidance on formulations, dosages, administration plans, and measurable therapeutic effects, please refer to works such as Berkow et al. (2000) The Merck Manual of Medical Information and Merck & Co. Inc., Whitehouse Station, New Jersey; Ebadi (1998) CRC Desk Reference of Clinical Pharmacology.

[0083] As those skilled in the art will understand, the above-mentioned pharmaceutical composition may further include a combination therapy agent (i.e., used in the form of combination therapy), which includes, but is not limited to, chemotherapeutic agents, radiotherapy agents, immunosuppressants, cytotoxic drugs, etc. When combination therapy is performed with a combination therapy agent, the above-mentioned antibody or its antigen-binding fragment, chimeric antigen receptor, genetically modified cells, antibody-drug conjugate, etc., and further therapeutic or diagnostic agents may each be used as a single agent within any time range suitable for performing the intended treatment or diagnosis. Therefore, these single agents may be administered substantially simultaneously (i.e., as a single formulation or within a few minutes or hours) or sequentially, depending on the actual needs of the specific application.

[0084] To solve the above technical problems, a tenth aspect of the present invention provides a kit comprising an antibody or antigen-binding fragment thereof as described in the first aspect of the present invention, a chimeric antigen receptor as described in the fifth aspect of the present invention, genetically modified cells as described in the sixth aspect of the present invention, an antibody-drug conjugate as described in the eighth aspect of the present invention, and / or a pharmaceutical composition as described in the ninth aspect of the present invention.

[0085] Preferably, the kit further comprises (i) a device for administering an antibody or its antigen-binding fragment or a chimeric antigen receptor or genetically modified cells or an antibody-drug conjugate or pharmaceutical composition, and / or (ii) instructions for use.

[0086] To solve the above technical problems, an eleventh aspect of the present invention provides applications of the antibody or antigen-binding fragment described in the first aspect of the present invention, the chimeric antigen receptor described in the fifth aspect of the present invention, the gene-modified cell described in the sixth aspect of the present invention, the antibody-drug conjugate described in the eighth aspect of the present invention, the pharmaceutical composition described in the ninth aspect of the present invention, and / or the kit described in the tenth aspect of the present invention in the manufacture of drugs for treating and / or preventing cancer.

[0087] Preferably, the cancer is selected from one or more of the group consisting of lung cancer, breast cancer, gastric cancer, small intestine cancer, colon cancer, rectal cancer, pancreatic cancer, kidney cancer, bladder cancer, and osteosarcoma.

[0088] To solve the above technical problems, a twelfth aspect of the present invention provides an administration device, the administration device comprising an antibody or antigen-binding fragment thereof as described in the first aspect of the present invention, a chimeric antigen receptor as described in the fifth aspect of the present invention, genetically modified cells as described in the sixth aspect of the present invention, an antibody-drug conjugate as described in the eighth aspect of the present invention, a pharmaceutical composition as described in the ninth aspect of the present invention, and / or a kit as described in the tenth aspect of the present invention.

[0089] Preferably, the administration device further includes a component for containing or administering to a subject the anti-B7-H7 antibody or its antigen-binding fragment, the chimeric antigen receptor, the genetically modified cells, the antibody-drug conjugate, the pharmaceutical composition and / or the kit, such as a syringe, an injector, or an implantable administration device.

[0090] To solve the above technical problems, a thirteenth aspect of the present invention provides a method for detecting B7-H7, the method comprising the step of detection using an antibody or antigen-binding fragment thereof as described in the first aspect of the present invention, a chimeric antigen receptor as described in the fifth aspect of the present invention, a genetically modified cell as described in the sixth aspect of the present invention, an antibody-drug conjugate as described in the eighth aspect of the present invention, a pharmaceutical composition as described in the ninth aspect of the present invention, and / or a kit as described in the tenth aspect of the present invention.

[0091] Preferably, the detection is not for the purpose of diagnosis and / or treatment, such as the detection of B7-H7 in basic research.

[0092] To solve the above technical problems, the present invention further provides applications of the antibody or antigen-binding fragment thereof described in the first aspect of the present invention, the chimeric antigen receptor described in the fifth aspect of the present invention, the gene-modified cell described in the sixth aspect of the present invention, the antibody-drug conjugate described in the eighth aspect of the present invention, the pharmaceutical composition described in the ninth aspect of the present invention, and / or the kit described in the tenth aspect of the present invention, in the prevention and / or treatment of cancer. Preferably, the cancer is as described in the eleventh aspect of the present invention.

[0093] To solve the above technical problems, the present invention further provides a method for treating and / or preventing B7-H7 related diseases or conditions (for example, cancer, preferably the cancer described in the 11th aspect of the present invention), the method comprising administering to a patient in need a therapeutically effective amount of the antibody or antigen-binding fragment described in the 1st aspect of the present invention, the chimeric antigen receptor described in the 5th aspect of the present invention, the genetically modified cells described in the 6th aspect of the present invention, the antibody-drug conjugate described in the 8th aspect of the present invention, the pharmaceutical composition described in the 9th aspect of the present invention, and / or the kit described in the 10th aspect of the present invention, thereby treating the patient in need.

[0094] In this application, unless otherwise specified, the scientific and technical terms used herein have meanings that are generally understood by those skilled in the art. Furthermore, the cell culture, molecular biology, nucleic acid chemistry, and immunology laboratory procedure steps used herein are all common steps widely used in their respective fields. In addition, to better understand the present invention, definitions and interpretations of relevant terms are provided below.

[0095] The three-letter and one-letter amino acid codes used in this application are either known to those skilled in the art or are as described in J. Biol. Chem, 243, p3558 (1968).

[0096] As used in this application, the terms “include” or “incorporate” mean that a composition and a method include such elements but does not exclude other elements, and may also include “consisting of…” depending on the context.

[0097] The term "antibody" as used in this application may include immunoglobulins, which are tetrapeptide chain structures consisting of two identical heavy chains and two identical light chains linked by interchain disulfide bonds. The constant regions of immunoglobulin heavy chains differ in their amino acid composition and sequence, and therefore their antigenicity also differs. This allows immunoglobulins to be divided into five classes, or they may be called immunoglobulin isotypes, namely IgM, IgD, IgG, IgA, and IgE, with their corresponding heavy chains being μ, δ, γ, α, and ε chains, respectively. Ig of the same class may be further divided into various subclasses based on differences in the amino acid composition of their hinge region and the number and position of heavy chain disulfide bonds; for example, IgG may be divided into IgG1, IgG2, IgG3, and IgG4. The light chains are divided into κ or λ chains based on their constant region. Each of the five classes of Ig may have either a κ or λ chain.

[0098] In this application, the antibody light chain variable region described herein may further include a light chain constant region, wherein the light chain constant region includes human-derived κ, λ chains or their variants. In this application, the antibody heavy chain variable region described herein may further include a heavy chain constant region, wherein the heavy chain constant region includes human-derived IgG1, 2, 3, 4 or their variants.

[0099] In the light and heavy chains, the variable and constant regions are linked via a "J" region of about 12 or more amino acids, and the heavy chain further includes a "D" region of about 3 or more amino acids. Each heavy chain consists of a heavy chain variable region (VH) and a heavy chain constant region (CH). The heavy chain constant region consists of three domains (CH1, CH2, and CH3). Each light chain consists of a light chain variable region (VL) and a light chain constant region (CL). The light chain constant region consists of one domain CL. The constant region of the antibody can mediate the binding of immunoglobulins to host tissues or factors, including various cells of the immune system (e.g., effector cells) and the first component of the classical complement system (C1q). Approximately 110 amino acids near the N-terminus of the antibody heavy and light chains are highly sequence-variable and constitute the variable region (V region), while other amino acids near the C-terminus have a relatively stable sequence and constitute the constant region (C region). The variable region includes three hypervariable regions (HVRs) and four relatively conserved skeletal regions (FWRs). The three hypervariable regions determine the specificity of the antibody and are also called complementarity-determining regions (CDRs). Each light chain variable region (VL) and heavy chain variable region (VH) consists of three CDR regions and four FWR regions, arranged sequentially from the amino group terminus to the carboxyl group terminus in the order FWR1, CDR1, FWR2, CDR2, FWR3, CDR3, and FWR4. The three CDR regions of the light chain refer to VL CDR1, VL CDR2, and VL CDR3, while the three CDR regions of the heavy chain refer to VH CDR1, VH CDR2, and VH CDR3.

[0100] The term "human antibody" includes antibodies having variable and constant regions that have human germline immunoglobulin sequences. The human antibodies of this application may include amino acid residues not encoded by human germline immunoglobulin sequences (e.g., mutations introduced by random or site-directed induction in vitro or somatic mutation in vivo). However, the term "human antibody" does not include antibodies (i.e., "humanized antibodies") in which a CDR sequence derived from the germline of another mammalian species (e.g., mouse) has already been transplanted into a human framework sequence.

[0101] As used in this application, the term “specificity” in relation to an antibody means an antibody that recognizes a specific antigen but substantially does not recognize or bind to other molecules in a sample. For example, an antibody that specifically binds to an antigen from one species may also bind to that antigen from one or more species. However, such interspecies cross-reactivity itself does not change the classification of antibodies based on specificity. In another example, an antibody that specifically binds to an antigen may also bind to different allele forms of that antigen. However, such cross-reactivity itself does not change the classification of antibodies based on specificity. In some cases, the terms “specificity” or “specific binding” can be used to refer to the interaction between an antibody, protein, or peptide and a second chemical substance, meaning that the interaction depends on the presence of a specific structure (e.g., an antigenic determinant or epitope) in the chemical substance, for example, an antibody generally recognizes and binds to a specific protein structure rather than a protein. If an antibody is specific to epitope “A”, in a reaction involving labeled “A” and the antibody, the presence of a molecule containing epitope A (or free, unlabeled A) reduces the amount of labeled A that binds to the antibody.

[0102] In this application, the term “antigen-binding fragment” refers to antigen-binding fragments and antibody analogs of antibodies, which typically include at least some antigen-binding regions or variable regions (e.g., one or more CDRs) of a parental antibody. The antibody fragment retains at least some binding specificity of the parental antibody. Typically, when expressed in molar terms, the antibody fragment retains at least 10% of the parental binding activity. Preferably, the antibody fragment retains at least 50%, 60%, 70%, 80%, 90%, 95%, 99%, or 100% or more of the binding affinity of the parental antibody to the target. Examples of antigen-binding fragments include, but are not limited to, Fab, Fab', F(ab')2, Fv fragments, linear antibodies, single (heavy) chain antibodies, nano antibodies, domain antibodies, and multispecific antibodies. Manipulated antibody variants are outlined in Holliger and Hudson (2005) Nat. Biotechnol. 23:1126-1136.

[0103] As used herein, the terms “chimeric antigen receptor” or “CAR” refer to an extracellular domain capable of binding to an antigen (extracellular binding domain), a hinge domain, a transmembrane domain (transmembrane region), and a polypeptide that transmits cytoplasmic signals to the domain (i.e., an intracellular signaling domain). The hinge domain may be considered to be a portion that provides flexibility to the extracellular antigen-binding region. The intracellular signaling domain generates signals that can enhance the immune effector function of the CAR in cells (e.g., CAR-T cells) through established signaling pathways, by generating second messengers to transmit information into the cell and modulate cellular activity, or by proteins that function as effectors in response to such messengers. The intracellular signaling domain includes a signaling domain and may further include a costimulatory intracellular domain from a costimulatory molecule.

[0104] "Identity" and "mutation" refer to sequence similarity between two polynucleotide sequences or between two polypeptides. The molecules are homologous at a given position if the positions in both comparison sequences are occupied by the same base or amino acid monomer subunit—for example, if the positions in each of the two DNA molecules are occupied by adenine. The percentage of identity between two sequences is a function of (number of matching or homologous positions shared by the two sequences divided by the number of positions being compared) multiplied by 100. For example, if, in optimal sequence alignment, 6 out of 10 positions in the two sequences match or are homologous, then the two sequences are 60% homologous. Generally, alignment of the two sequences is performed to obtain the highest possible percentage of identity.

[0105] The terms “polypeptide,” “peptide,” and “protein” (in the case of a single chain) are interchangeable in this application. The terms “nucleic acid,” “nucleic acid sequence,” “nucleotide sequence,” or “polynucleotide sequence,” and “polynucleotide” are interchangeable.

[0106] The term "vector" refers to a nucleic acid delivery medium into which polynucleotides can be inserted. If a vector enables the expression of a protein encoded by the inserted polynucleotide, it is called an expression vector. A vector can be introduced into a host cell by means of transformation, transduction, or transtransfer, and the genetic material elements it carries can be expressed in the host cell. Vectors are well known to those skilled in the art and include, but are not limited to, plasmids, phagemids, cosmids, artificial chromosomes, e.g., yeast artificial chromosomes (YACs), bacterial artificial chromosomes (BACs), or P1-derived artificial chromosomes (PACs), λ phages or M13 phages, and phages such as animal viruses. Animal viruses that can be used as vectors include, but are not limited to, retroviruses (including lentiviruses), adenoviruses, adeno-associated viruses, herpesviruses (e.g., herpes simplex virus), poxviruses, baculoviruses, papillomaviruses, and papovaviruses (SV40). The vector may contain multiple elements that control expression, including, but not limited to, a promoter sequence, a transcription initiation sequence, an enhancer sequence, a selection element, and a reporter gene. The vector may also further contain a replication initiation site.

[0107] The terms “cell” and “cell line” as used in this application are interchangeable, and all such names include their offspring. The term “host cell” refers to a cell that can be used to introduce a vector, and includes, but is not limited to, prokaryotic cells such as Escherichia coli, fungal cells such as yeast cells, or animal cells such as fibroblasts, CHO cells, COS cells, NSO cells, HeLa cells, BHK cells, HEK 293 cells, or human cells.

[0108] The term "transfection" refers to the introduction of exogenous nucleic acids into eukaryotic cells. Transfection can be achieved by a variety of means known in this field, including calcium phosphate-DNA coprecipitation, DEAE-dextran-mediated transfection, polybrene-mediated transfection, electroporation, microinjection, liposome fusion, lipofection, protoplast fusion, retroviral infection, and biolytic techniques.

[0109] The term “immune cells” refers to cells capable of inducing an immune response, and “immune cells” and other grammatical forms thereof can refer to immune cells of any origin. “Immune cells” include, for example, leukocytes (white blood cells), lymphocytes (T cells, B cells, natural killer (NK) cells), and cells derived from bone marrow (neutrophils, eosinophils, basophils, monocytes, macrophages, dendritic cells), derived from hematopoietic stem cells (HSCs) produced in the bone marrow. The term “immune cells” may be human or non-human. For example, immune cells may be derived from blood, such as autologous T cells, allogeneic T cells, autologous NK cells, allogeneic NK cells, or from cell lines, such as NK cell lines obtained by EBV virus infection, NK cells induced and differentiated from embryonic stem cells and iPSCs, and NK92 cell lines.

[0110] As used in this application, the term “T cell” refers to a class of lymphocytes that mature in the thymus. T cells play a crucial role in cell-mediated immunity and are distinguished from other lymphocytes (e.g., B cells) by the presence of T cell receptors on their cell surface. “T cells” include all types of CD3-expressing immune cells, including T helper cells (CD4+ cells), cytotoxic T cells (CD8+ cells), natural killer T cells, T regulatory cells (Treg), and γ-δ T cells. “Cytotoxic cells” include CD8+ T cells, natural killer (NK) cells, and neutrophils, which can mediate cytotoxic responses. As used herein, the term “NK cell” refers to a class of lymphocytes that originate in the bone marrow and play a crucial role in the innate immune system. NK cells provide a rapid immune response to virus-infected cells, tumor cells, or other stressed cells, even without the presence of antibodies and major histocompatibility conjugates on their cell surface.

[0111] The terms “optional,” “any one,” “optional,” or “any one” mean that the events or conditions described later may occur but are not required, and the description includes cases where the events or conditions have occurred or not. For example, “optionally containing one antibody heavy chain variable region” means that an antibody heavy chain variable region of a particular sequence may be present but is not necessarily present. As used in this invention, “one” and “one type” refer to one or more grammatical objects. Unless the context explicitly indicates otherwise, the term “or” in this invention means “and / or” and is used interchangeably. “About” and “approximately” are typically used to refer to the degree of error in a measured quantity, depending on the nature or precision of the measurement. The degree of exemplary error is generally within 10%, and more generally within 5%. The methods and compositions disclosed in this invention include polypeptides and nucleic acids having a predetermined sequence, a variant sequence, or a substantially homologous or similar sequence, for example, a sequence that is at least 85%, 90%, 95%, 99%, or more identical to the predetermined sequence. In the case of amino acid sequences, the term “substantially identical” is used in this invention to refer to a first amino acid sequence.

[0112] As used herein, the term “pharmaceutical composition” means a formulation in which the biological activity of the active ingredient is permitted to be effective and which does not contain other ingredients that are unacceptable to the subject to which the composition is administered. The composition is sterile.

[0113] As used in this application, the term “pharmaceutically acceptable vector” refers to a carrier that is pharmacologically and / or physiologically compatible with the subject and the active ingredient, and which is known in the art (see, for example, Remington's Pharmaceutical Sciences, Edited by Gennaro AR, 19th ed. Pennsylvania: Mack Publishing Company, 1995), and which includes, but is not limited to, pH adjusters, surfactants, adjuvants, ionic strength enhancers, diluents, osmotic pressure-maintaining reagents, absorption-delaying reagents, and preservatives. For example, pH adjusters include, but are not limited to, phosphate buffers. Surfactants include, but are not limited to, cationic, anionic, or nonionic surfactants, such as Tween-80. Ionic strength enhancers include, but are not limited to, sodium chloride. Preservatives include, but are not limited to, a variety of antibacterial and antifungal reagents, such as parabens, chlorobutanol, phenol, and sorbic acid. Reagents for maintaining osmotic pressure include, but are not limited to, sugars, NaCl, and their analogues. Reagents for slowing absorption include, but are not limited to, monostearates and gelatin. Diluents include, but are not limited to, water, aqueous buffers (e.g., buffered saline), ols, and polyols (e.g., glycerol). Preservatives include, but are not limited to, various antibacterial and antifungal reagents, such as thimerosal, 2-phenoxyethanol, parabens, chlorobutanol, phenol, and sorbic acid. Stabilizers have a meaning generally understood by those skilled in the art and can stabilize the desired activity of the active ingredient in a pharmaceutical product, and include, but are not limited to, monosodium glutamate, gelatin, SPGA, sugars (e.g., sorbitol, mannitol, starch, sucrose, lactose, dextran, or glucose), amino acids (e.g., glutamic acid, glycine), proteins (e.g., dried whey, albumin, or casein) or their degradation products (e.g., lactalbumin hydrolysate).

[0114] As used herein, EC 50The term refers to the concentration for 50% of the maximal effect, that is, the concentration that can produce 50% of the maximum effect response.

[0115] As used in this invention, “cancer,” “cancer,” and “cancer patient” are intended to include all types of cancerous growths or tumorigenetic processes, metastatic tissues or malignant transformed cells, tissues, or organs, regardless of histopathological type or stage of invasiveness. Examples include, but are not limited to, solid tumors, hematological malignancies, soft tissue tumors, and metastatic lesions.

[0116] As those skilled in the art will understand, products containing the anti-B7-H7 antibody or its antigen-binding fragment as described in the present invention, such as CAR-T, TCR-T, diabody, multibody, ADC, and other product forms, should fall within the scope of protection of the present invention.

[0117] By arbitrarily combining the above preferred conditions while being consistent with common sense in the art, various preferred examples of the present invention can be obtained.

[0118] All reagents and raw materials used in this invention are commercially available.

[0119] The positive effects of the present invention are that the anti-B7-H7 antibody or its antigen-binding fragment described in the present invention has high affinity and high biological activity for B7-H7, and can effectively block the binding of the B7-H7 protein to its receptor CD28H and to its receptor KIR3DL3. Furthermore, the anti-B7-H7 antibody or its antigen-binding fragment of the present invention specifically binds only to the B7-H7 protein, does not cross-react with other member proteins of the B7 family, and has excellent stability. In addition, the anti-B7-H7 antibody or its antigen-binding fragment of the present invention exhibits high in vivo antitumor activity. [Brief explanation of the drawing]

[0120] [Figure 1]This figure shows the results of the B7-H7 primary antibody binding to human, cynomolgus monkey B7H7, and tumor cell HCC827 on the cell surface. [Figure 2] This figure shows the results of the B7-H7 LALA mutant antibody binding to LS180 on tumor cells. [Figure 3] This figure shows the results of binding of the B7-H7 PTM mutant / LALA mutant antibody to LS180 on tumor cells. [Figure 4] This figure shows that the B7-H7 antibody blocks the binding of the B7-H7 protein to CD28H on the surface of HEK-293 cells. [Figure 5] This figure shows that B7-H7 antibodies and LALA mutant antibodies block the binding of the B7-H7 protein to KIR3DL3 on the surface of CHO-K1 cells. [Figure 6] This figure shows that the B7-H7 antibody LALA mutant antibody blocks the binding of the B7-H7 protein to the KIR3DL3 protein. [Figure 7] This figure shows that the B7-H7 antibody activates T cells by blocking the immunosuppressive signal of B7-H7. [Figure 8] This figure shows that the B7-H7 antibody did not act on B7-H7 negative cells and was unable to activate T cells. [Figure 9] This figure shows that the B7-H7 antibody promotes the killing of target cells by NK cells. [Figure 10] This figure shows the results of cross-reactivity between the anti-B7-H7 LALA mutant antibody and other member proteins of the B7 family. [Figure 11] This figure shows the serum stability results for the anti-B7-H7 LALA mutant antibody. [Figure 12] This figure shows the results of the antitumor effect of anti-B7-H7 antibody in a mouse tumor model. [Modes for carrying out the invention]

[0121] The present invention will be further described below using the methods of the examples, but the present invention is not limited to the scope of the above examples. In the following examples, experimental methods for which specific conditions are not specified shall be selected according to conventional methods and conditions or product descriptions.

[0122] Example 1. Acquisition of anti-B7-H7 antibody molecule Experimental animals are immunized with B7-H7 recombinant protein to obtain antibody molecules that specifically bind to B7-H7. These experimental animals may be mice, rats, rabbits, sheep, camels, etc. Typically, the obtained antibody molecules are of non-human origin. After obtaining non-human antibodies, it is necessary to perform humanization operations on these molecules using antibody engineering techniques to reduce immunogenicity and increase drug discovery potential. However, the humanization process of antibodies is technically complex, and humanized molecules often have reduced affinity for antigens. On the other hand, advances in transgenic technology have made it possible to create genetically modified mice that possess an immune repertoire of human immunoglobulins and have a deletion of their endogenous mouse immune repertoire. Harbour H2L2 mice (Harbour Antibodies BV) are transgenic mice that possess an immune repertoire of human immunoglobulins, and antibodies produced from such transgenic mice have a completely human-derived sequence and therefore do not require further humanization operations.

[0123] Example 1.1. Mouse Immunization Harbour H2L2 mice were immunized multiple times with soluble recombinant human B7-H7-ECD-his fusion protein (Sino Biological, #16139-H08H) as the antigen. The antigen protein and immunoadjuvant were mixed to form an immunogen reagent, which was then administered subcutaneously via inguinal injection or intraperitoneally. In each round of immunization, each mouse received a total injection volume of 100 microliters. In the initial immunization, each mouse was immunized with an immunogen reagent prepared by mixing 50 micrograms of antigen protein with complete Freund's adjuvant (Sigma, #F5881) in a 1:1 volume ratio. In subsequent rounds of immunization, each mouse was immunized with an immunogen reagent prepared by mixing 25 micrograms of antigen protein with Sigma Adjuvant System adjuvant (Sigma, #S6322). The interval between each round of immunization was at least two weeks, and typically there were 4-5 rounds of immunization. Immunization times were days 0, 14, 28, 42, 56, 70, 84, and 96, and antibody titers in mouse serum were detected on days 49 and 77. A final booster immunization was performed with a dose of 25 micrograms of antigen protein per mouse, 5 days before isolation of spleen B cells from H2L2 mice.

[0124] Example 1.2. Detection of serum titer At specific time points, mouse serum was collected, and the binding titer of antibodies to the B7-H7 protein in the serum was detected by ELISA, while the binding titer of antibodies to B7-H7 overexpressing cells in the serum was detected by FACS.

[0125] In the ELISA method, ELISA plates (corning, 9018) were coated with 1 μg / mL of hB7-H7-ECD-hFc protein (Sino Biological, #16139-H02H) at a rate of 100 μL / well, incubated overnight at 4°C, rinsed twice, then blocked with 1% BSA-containing PBST at 37°C for 2 hours, incubated with 100 μL / well of serially diluted serum at 37°C for 1 hour, rinsed three times, and then 100 μL / well of anti-rat-HRP (sigma, #A5795) diluted 1:5000 was added, followed by incubation at 37°C for 30 minutes. After rinsing three times, 100 μL / well of TMB substrate was added, incubated for approximately 10 minutes, and 50 μL / well of 1N HCl was added to stop the color development. The absorbance at 450 nm was then read (Molecular Devices, Plus 384).

[0126] In the FACS method, serially diluted mouse serum and HEK293-B7-H7 cells were incubated at 4°C for 1 hour, washed twice, and then the secondary antibody anti-rat IgG(H+L) (Life Technologies, A11006) was added and incubated at 4°C for 1 hour, washed twice, and the cells were resuspended and detected by flow cytometry (BD, Flibur). HEK293 cells were used as a background control.

[0127] Example 1.3. Screening of anti-B7-H7 antibodies using hybridoma technology Immunized mice with high serum titers were selected, and after a single final immunization, the mice were sacrificed. Splenocytes and SP2 / 0 myeloma cells (ATCC, CRL-1581) were taken and electrofusion was performed with a cell ratio of 4:1. The electrofusion parameters were V1:50V, t1:15s, V2:600V, t2:20μs, t3:0.5s, n:1, t4:7s, V+ / -:+, fade:on. The cells were resuspended in a DMEM culture medium containing 20% ​​FBS and HT, and 1 × 10⁶ cells were extracted. 5Cells were seeded at 100 μL / well, and after 24 hours, 100 μL / well of DMEM containing 20% ​​FBS and 2×HT was added and cultured. The supernatant was then collected and antibody titer was detected. Generally, 9-15 days after fusion, the supernatant was collected from protein-immunized mice and preliminary screening was performed with Acumen to detect binding to HEK-293 / huB7-H7 cells. Positive clones were then further confirmed by ELISA and FACS to detect binding ability to HEK-293 cell lines overexpressing human B7-H7 (HEK-293 / huB7-H7) and HEK-293 cell lines overexpressing cynomolgus monkey B7-H7 (HEK-293 / cynoB7-H7). Positive wells were further subcloned using the finite dilution method, and then further cloned using ELISA and FACS. Clones that bound well to human and monkey B7-H7 were selected and sequenced.

[0128] Example 1.4. Sequence analysis and sequence optimization of anti-B7-H7 antibody Conventional sequencing methods were used to obtain the nucleotide sequences encoding the variable domain of the antibody molecule and the corresponding amino acid sequences. Fourteen monoclonal sequences were obtained. In this example, the sequence of the variable domain of the anti-B7-H7 monoclonal antibody molecule obtained from immunized Harbour H2L2 mice is a human-derived antibody sequence, and Table 1-1 lists its germline gene analysis and post-translational modification site (PTM) analysis.

[0129] The amino acid chains of proteins or polypeptides may undergo chemical modifications called post-translational modifications (PTMs) after translation and synthesis within cells. In the case of antibodies, some PTM sites are highly conserved; for example, the conserved amino acid asparagine (Asn) at position 297 (EU number) of the constant domain of human IgG1 antibodies usually undergoes glycosylation modification to form a sugar chain, and this sugar chain structure is quite important for the antibody structure and associated effector function. However, if PTMs are present in the variable domain of the antibody, particularly in the antigen-binding region (e.g., CDR), the presence of these PTMs can significantly affect antigen binding and alter the physicochemical properties of the antibody. For example, glycosylation, deamidation, isomerization, and oxidation can all increase the instability or heterogeneity of the antibody molecule, potentially increasing the difficulty and risk of antibody development. Therefore, avoiding some potential PTMs is crucial for the development of therapeutic antibodies. Through accumulated experience, it has been discovered that some PTMs are highly correlated with the composition of amino acid sequences, particularly the "patterns" of adjacent amino acid compositions, allowing for the prediction of potential PTMs from the primary amino acid sequence of a protein. For example, the N-linked glycosylation site can be predicted from the sequence pattern NxS / T (asparagine at position 1, any non-proline amino acid at position 2, and serine or threonine at position 3). The amino acid sequence patterns that cause PTMs may originate from germline gene sequences, such as the human germline gene fragment IGHV3-33, in which the glycosylation pattern NST naturally exists in the FR3 region, or they may originate from somatic high-frequency mutations.

[0130] By disrupting the amino acid sequence pattern of a PTM through amino acid mutations, the formation of a specific PTM can be reduced or eliminated. The method of designing the mutations varies depending on the antibody sequence and the PTM sequence pattern. One method involves replacing a "hotspot" amino acid (e.g., N or S in an NS pattern) with an amino acid that has similar physicochemical properties (e.g., mutating N to Q). If the PTM sequence pattern originates from somatic high-frequency mutations but is not present in germline gene sequences, another method is to replace the sequence pattern with the corresponding germline gene sequence. In practice, various mutation design methods can be used for the same PTM sequence pattern.

[0131] Table 1-2 lists novel antibody molecular sequences obtained by performing amino acid mutations on the sequences of antibodies PR003249, PR003259, and PR003264. Here, PR003181 is the positive control and is derived from patent WO2014190356.

[0132] [Table 1]

[0133] [Table 2]

[0134] Example 1.5. Production of recombinant antibodies and characterization analysis of their physicochemical properties Example 1.5.1. Antibody Expression and Purification This example describes a general method for producing antibodies using mammalian host cells (e.g., human embryonic kidney cells HEK293 or Chinese hamster ovary cells CHO and cells derived therefrom), transient transfection expression, and affinity capture isolation. This method is suitable for target antibodies containing an Fc region, which may consist of one or more protein polypeptide chains or be derived from one or more expression plasmids.

[0135] The amino acid sequence of the antibody polypeptide chain was converted to a nucleotide sequence using a codon optimization method, the encoded nucleotide sequence was synthesized, and it was cloned into an expression vector compatible with host cells. By simultaneously transfecting mammalian host cells with plasmids encoding the antibody polypeptide chain in a specific proportion, recombinant antibodies with accurate folding and polypeptide chain assembly can be obtained using conventional recombinant protein expression and purification techniques. Specifically, FreeStyle® 293-F cells (Thermo, #R79007) were cultured in FreeStyle® F17 Expression Medium (Thermo, #A1383504). Before transient transfection was initiated, the cell concentration was increased to 6-8 × 10⁶. 5 Adjust the concentration to cells / mL, and culture in a shaker at 37°C and 8% CO2 for 24 hours until the cell concentration reaches 1.2 × 10⁶. 6The cell-to-cell ratio is 1 / mL. 30 mL of cultured cells was prepared. Plasmids encoding antibody polypeptide chains were mixed in a fixed ratio, and a total of 30 μg of plasmid (plasmid-to-cell ratio of 1 μg:1 mL) was dissolved in 1.5 mL of Opti-MEM serum-reduced medium (Thermo, #31985088), filtered through a 0.22 μm filter membrane, and sterilized. Next, 1.5 mL of Opti-MEM was taken and dissolved in 120 μL of 1 mg / mL PEI (Polysciences, #23966-2), and allowed to stand for 5 minutes. PEI was slowly added to the plasmid, incubated at room temperature for 10 minutes, and the plasmid-PEI mixture was slowly added dropwise while gently shaking the culture flask. The culture was then incubated at 37°C in an 8% CO2 shaker for 5 days. Cell viability was observed after 5 days. The culture was collected, centrifuged at 3300 g for 10 minutes, the supernatant was taken, and the supernatant was centrifuged at high speed to remove impurities. A gravity column (Bio-Rad, #7311550) containing MabSelect® (GE Healthcare, #71-5020-91) was equilibrated with PBS pH 7.4 buffer and washed with 2 to 5 times the column volume. The supernatant sample was passed through the column and washed with 5 to 10 times the column volume of PBS buffer. The target protein was then eluted with 0.1 M glycine at pH 3.5, followed by neutralization with Tris-HCl at pH 8.0. Finally, the solution was concentrated in an ultrafiltration tube (Millipore, #UFC901024), replaced with PBS buffer or a buffer containing other components, and a purified recombinant antibody solution was obtained. Finally, the concentration was measured using NanoDrop (Thermo, NanoDrop® One), aliquoted, and stored for awaiting.

[0136] Example 1.5.2. Analysis of protein purity and aggregates by SEC-HPLC In this example, the purity and aggregate form of protein samples were analyzed using analytical size exclusion chromatography (SEC). An analytical chromatography column, TSKgel G3000SWxl (Tosoh Bioscience, #08541, 5 μm, 7.8 mm × 30 cm), was connected to a high-performance liquid chromatography (HPLC) system (Agilent Technologies, Agilent 1260 Infinity II) and equilibrated with PBS buffer at room temperature for at least 1 hour. An appropriate amount of protein sample (at least 10 μg) was filtered through a 0.22 μm filtration membrane and injected into the system. The HPLC procedure was set up, and the sample was passed through the chromatography column at a flow rate of 1.0 mL / min using PBS buffer for a maximum time of 25 minutes. The HPLC generated an analytical report, which reported the retention times of components of different molecular sizes in the sample.

[0137] Example 1.5.3. Analysis of protein purity and hydrophobicity by HIC-HPLC The purity and hydrophobicity of protein samples were analyzed using analytical hydrophobic interaction chromatography (HIC). An analytical chromatography column, TSKge1 Buty1-NPR (Tosoh Bioscience, 14947, 4.6 mm × 3.5 cm), was connected to a high-performance liquid chromatography (HPLC) system (Agilent Technologies, Agilent 1260 Infinity II) and equilibrated with PBS buffer at room temperature for at least 1 hour. The method was set to a 16-minute linear gradient from 100% mobile phase A (20 mm histidine, 1.8 M ammonium sulfate, pH 6.0) to 100% mobile phase B (20 mm histidine, pH 6.0), with a flow rate of 0.7 mL / min, a protein sample concentration of 1 mg / mL, a sample injection volume of 20 μL, and a detection wavelength of 280 nm. After sampling, the chromatogram was integrated using ChemStation software, relevant data were calculated, and an analytical report was prepared, reporting the retention times of components of different molecular sizes in the sample.

[0138] Example 1.5.4. Measurement of the thermal stability of protein molecules using DSF Differential scanning fluorescence (DSF) is a high-throughput method commonly used to measure the thermal stability of proteins. It reflects the process of protein denaturation and thus the thermal stability of the protein molecule by monitoring the change in fluorescence intensity of a dye bound to an unfolded protein molecule using a real-time fluorescence quantitative PCR instrument. In this example, the thermal denaturation temperature (Tm) of a protein molecule was measured using the DSF method. 10 μg of protein was added to a 96-well PCR plate (Thermo, #AB-0700 / W), then 2 μl of 100× diluted dye SYPRO™ (Invitrogen, #2008138) was added, and buffer was added to bring the final volume to 40 μl / well. The PCR plate was sealed and placed in a real-time fluorescence quantitative PCR instrument (Bio-Rad CFX96 PCR System). It was first incubated at 25°C for 5 minutes, then gradually heated from 25°C to 95°C with a gradient of 0.2°C / 0.2 minutes, and finally cooled back down to 25°C at the end of the test. Using FRET scanning mode, the data was analyzed with Bio-Rad CFX Maestro software, and the Tm of the sample was calculated.

[0139] Example 1.6. Production of fully human recombinant anti-B7-H7 antibody Using the method described in Example 1.5, fully human-derived IgG antibodies against anti-B7-H7 obtained in Example 1.6 were prepared and analyzed. Tables 1-3 and 1-4 list the results of transient expression purification in small and large volumes, respectively. In addition, anti-B7-H7 antibody sequences (Table 1-5) were obtained from conventional literature and used as controls in subsequent experiments.

[0140] [Table 3]

[0141] [Table 4]

[0142] [Table 5]

[0143] Example 1.7. Anti-B7-H7 antibody sequence and number The amino acid sequences of the CDRs of the antibodies obtained in this invention are shown in the table below, and all of these CDRs are shown according to the Chothia definition rules.

[0144] [Table 6] Here, Laa-Lbb may refer to the amino acid sequence from position aa (Chothia numbering rule) to position bb (Chothia numbering rule) from the N-terminus of the antibody light chain, and Haa-Hbb may refer to the amino acid sequence from position aa (Chothia numbering rule) to position bb (Chothia numbering rule) from the N-terminus of the antibody heavy chain. For example, L24-L34 may refer to the amino acid sequence from position 24 to 34 according to the Chothia numbering rule from the N-terminus of the antibody light chain, and H26-H35 may refer to the amino acid sequence from position 26 to 35 according to the Chothia numbering rule from the N-terminus of the antibody heavy chain. As those skilled in the art will know, when encoding a CDR with Chothia, there may be insertion sites at several positions (see http: / / bioinf.org.uk / abs / ).

[0145] Tables 1-7-1 and 1-7-2 list the sequence numbers corresponding to the sequences of the anti-B7-H7 antibody and control antibody molecules of the present invention.

[0146] [Table 7-1] [Table 7-2] [Table 7-3]

[0147] [Table 8-1] [Table 8-2]

[0148] Example 2. Detection of B7-H7 antibody binding ability to B7-H7 by FACS This example aims to study the in vitro binding activity of an anti-human B7-H7 H2L2 monoclonal antibody to human / cynomolgus monkey B7-H7. Since B7-H7 homologous molecules are absent in mice, detection was not performed. Antibody binding experiments at the cell level were performed using HEK-293 cell lines overexpressing human B7-H7 (HEK-293 / hu B7-H7, Wahaku Pharmaceutical), HEK-293 cell lines overexpressing cynomolgus monkey B7-H7 (HEK-293 / cyno B7-H7, Wahaku Pharmaceutical), or cell lines highly expressing human B7-H7, such as HCC827 (ATCC® CRL-2868) and LS180 (Nanjing Kebai, CBP60034). In short, HEK-293 / hu B7-H7 cells, HEK-293 / cyno B7-H7 cells, HCC827 cells, or LS180 cells were digested and resuspended in PBS containing 2% BSA. The cell density was set to 1 × 10⁶ for each cell type. 6The solution was adjusted to cells / mL. 100 μL of cells / well was inoculated into a 96-well V-bottom plate (Corning, #3894), and then 100 μL / well of the target antibody, serially diluted to a 3-fold concentration (twice the final concentration), was added. The cells were incubated at 4°C for 2 hours in the dark. Then, 100 μL / well of pre-cooled 2% BSA-containing PBS was added, the cells were rinsed twice, and the mixture was centrifuged at 500 g at 4°C for 5 minutes, discarding the supernatant. Next, 100 μL / well of the fluorescent secondary antibody (Alexa Fluor 488-conjugated AffiniPure Goat Anti-Human IgG, Fcγ Fragment Specific, Jackson, #109-545-098, 1:500 dilution) was added, and the mixture was incubated at 4°C for 1 hour in the dark. The cells were washed twice with 100 μL / well of pre-cooled PBS containing 2% BSA, centrifuged at 500 g at 4°C for 5 minutes, and the supernatant was discarded. Finally, the cells were resuspended in 200 μL / well of pre-cooled PBS containing 2% BSA, and the fluorescence signal values ​​were read using ACEA Novocyte3000 flow cytometry.

[0149] The binding of antibodies to human B7-H7, cynomolgus monkey B7-H7, and tumor cells HCC827 and LS180 on the cell surface is summarized below (Tables 2-1, 2-2, and 2-3).

[0150] [Table 9] ~ indicates that the coupling is weak, making it impossible to fit the curve and calculate the maximum MFI and EC50.

[0151] [Table 10] ~ indicates that the coupling is weak, making it impossible to fit the curve and calculate the maximum MFI and EC50.

[0152] [Table 11] The results for human B7-H7 on the surface of primary antibodies are shown in AF of Figure 1. The results indicate that these primary antibodies have excellent binding activity to human and cynomolgus monkey B7-H7 and can bind to B7-H7 on the surface of tumor cells. By performing LALA mutations on the Fc terminus of PR003181, PR003249, PR003259, and PR003264 to remove the ADCC effect, the modified antibodies PR004260, PR004261, PR004262, and PR004263 were shown to have cell binding activity consistent with the primary antibodies (Figure 2). Furthermore, by removing PTM from PR004261 and PR004262, antibodies PR004479-PR004494 were obtained, and FACS results showed that their binding activity was substantially consistent with that of the primary antibodies (Figure 3).

[0153] Example 3. Antibody-mediated blockade of the binding of human B7-H7 protein to HEK293 cells overexpressing human CD28H. This study aims to investigate the in vitro blocking activity of human anti-B7-H7 antibodies in blocking the binding of human B7-H7 to its receptor, CD28H. Using the HEK-293 cell line (HEK-293 / CD28H, Wahaku Pharmaceutical), which overexpresses human CD28H, experiments were conducted to block human B7-H7 / human CD28H binding at the cellular level. Simply put, HEK-293 / CD28H cells were digested and resuspended in PBS containing 2% BSA. The cell density was set to 1 × 10⁻⁶. 6The solution was adjusted to cells / mL. 100 μL of cells / well was inoculated into a 96-well V-bottom plate (Corning, Cat#:3894). Subsequently, 100 μL / well of the target antigen-binding protein, serially diluted to a 3-fold concentration (twice the final concentration), was added and mixed uniformly. The maximum concentration of the antigen-binding protein was 100 nM, with a total concentration of 8 cells. hIgG was used as a control. The cells were incubated at 4°C for 1 hour in the dark. Then, the cells were centrifuged at 4°C for 5 minutes, the supernatant discarded, and 50 μL / well of biotin-labeled human B7-H7 protein (Acro Biosystems, B77-H82F5) at a concentration of 1 μg / mL was added. The cells were incubated at 4°C for 30 minutes in the dark. 100 μL / well of pre-cooled PBS containing 2% BSA was added, the cells were rinsed twice, and the cells were centrifuged at 500 g at 4°C for 5 minutes. The supernatant was discarded. Fluorescent secondary antibody (PE Streptavidin, BD, Cat#:554061, 1:200) was added at 100 μL / well and incubated at 4°C in the dark for 30 minutes. Cells were washed twice with 200 μL / well of pre-cooled PBS, centrifuged at 500 g at 4°C for 5 minutes, and the supernatant was discarded. Finally, cells were resuspended in 200 μL / well of pre-cooled PBS, and fluorescence signal values ​​were read using ACEA Novocyte3000 flow cytometry. IC50 was calculated.

[0154] The results are shown in Figure 4 and Table 3. The blocking efficiency of PR003251, PR003254, PR003260, PR003262, PR003263, and PR003181 was not poor, and the other antibodies were able to completely block the binding of the B7-H7 protein to its receptor CD28H, all of which performed better than the positive control PR003181.

[0155] [Table 12]

[0156] Example 4. Antibody-mediated blockade of the binding of human B7-H7 protein to human KIR3DL3 protein and CHO-K1 cells overexpressing KIR3DL3. Example 4.1. Antibody-mediated blockade of the binding of human B7-H7 protein to KIR3DL3 expressed on the cell surface. This study aims to investigate the in vitro blocking activity of human anti-B7-H7 antibodies against the binding of human B7-H7 to its receptor, KIR3DL3. Using CHO-K1 cells (CHO-K1 / KIR3DL3, Wahaku Pharmaceutical) overexpressing human KIR3DL3, cell-level human B7-H7 / human KIR3DL3 binding blocking experiments were performed. Simply put, CHO-K1 / KIR3DL3 cells were digested and resuspended in PBS containing 2% BSA. The cell density was set to 1x10⁻⁶. 6 The solution was adjusted to cells / mL. 100 μL of cells / well was inoculated into a 96-well V-bottom plate (Corning, Cat#:3894). Subsequently, 100 μL / well of the target antigen-binding protein, serially diluted to a 3-fold concentration (twice the final concentration), was added and mixed uniformly. The maximum concentration of the antigen-binding protein was 100 nM, with a total concentration of 8 cells. hIgG was used as a control. The cells were incubated at 4°C for 1 hour in the dark. Then, the cells were centrifuged at 4°C for 5 minutes, the supernatant discarded, and 50 μL / well of biotin-labeled human B7-H7 protein (Acro Biosystems, B77-H82F5) at a concentration of 1 μg / mL was added. The cells were incubated at 4°C for 30 minutes in the dark. 100 μL / well of pre-cooled PBS containing 2% BSA was added, the cells were rinsed twice, and the cells were centrifuged at 500 g at 4°C for 5 minutes. The supernatant was discarded. Fluorescent secondary antibody (PE Streptavidin, BD, Cat#:554061, 1:200) was added at 100 μL / well and incubated at 4°C in the dark for 30 minutes. Cells were washed twice with 200 μL / well of pre-cooled PBS, centrifuged at 500 g at 4°C for 5 minutes, and the supernatant was discarded. Finally, cells were resuspended in 200 μL / well of pre-cooled PBS, and fluorescence signal values ​​were read using ACEA Novocyte3000 flow cytometry. IC50 was calculated.

[0157] The results are shown in Figure 5 and Table 4, demonstrating that, with the exception of the control IgG, all antibodies were able to completely block the binding of the B7-H7 protein to its receptor KIR3DL3.

[0158] [Table 13]

[0159] Example 4.2. Antibody-mediated blockade of the binding of human B7-H7 protein to human KIR3DL3 protein. Human KIR3DL3 (Sino Biological, Cat# 16055-H08H) was diluted to 5 μg / ml in PBS and added to a 96-well plate (Corning, cat# 9018) at a rate of 100 μl / well. The plate was incubated overnight at 4°C. After discarding the liquid, the plate was washed three times with PBS buffer. 200 μl of PBS mounting medium containing 1% BSA was added, and the plate was incubated at room temperature for 1 hour. The mounting medium was discarded, and the plate was washed three times with PBS buffer. Different concentrations of target antibodies and 6 μg / ml biotin-B7H7 protein (Acro Biosystems, Cat# B77-H82F5) or Biotin-B7H4 protein (Acro Biosystems, Cat# B74-H82E2) were added. Biotin-B7H4 protein is a negative control protein and does not bind to KIR3DL3. The target antibody was sequentially diluted 3-fold in a total of eight concentration gradients, starting from a 100 nM concentration. 100 μl was added to each well and incubated overnight at 4°C. After washing three times with PBS buffer, 500-fold diluted StrepTactin-HRP Conjugate (Bio-rad, Cat# 161-0380) was added, and incubated at 37°C in the dark for 1 hour. After washing four times with PBS buffer, 100 μL / well of TMB (KPL SureBlue, Cat# 5120-0077) was added, and the mixture was left at room temperature in the dark for approximately 10 minutes. The reaction was stopped by adding 100 μL / well of stop solution (BBI life sciences, Cat# E661006-0200) to each well, and the absorbance values ​​at 450 nm were measured using a plate reader (PerkinElemer #Enspire).

[0160] The results are as shown in Fig. 6. The B7-H7 protein can bind to the KIR3DL3 protein in the absence of antibodies, while the B7-H4 protein cannot bind. The detection target antibodies PR004261, PR004262, and PR004263 can dose-dependently block the binding between the B7-H7 protein and the KIR3DL3 protein.

[0161] Example 5. Detection of T cell activation activity To detect the function of anti-B7-H7 antibodies to activate T cells by blocking T cell immune checkpoints, this experiment used anti-human CD3 antibody OKT3 overexpressing full-length B7-H7 and scFv forms in CHO-K1 cells as artificial antigen-presenting cells (CHO-K1 / OS8 / hB7-H7, Beijing Kangyuan) or negative control cells (CHO-K1 / OS8, Beijing Kangyuan). Using a human T cell isolation kit (Miltenyi, #130-096-535), T cells were isolated according to the method in the instruction manual, and the artificial antigen-presenting cells and T cells were co-cultured to detect the effect of anti-B7-H7 antibodies on T cell activation. Specifically, CHO-K1-OS8-hB7-H7 or the control cell CHO-K1-OS8 was seeded at a density of 1×10 4 / well and cultured overnight. Human primary T cells were isolated and 2×10 5The solution was added to CHO-K1-OS8-hB7-H7 cells at a density of 100 μl / well. Subsequently, 100 μL / well of the target antibody, serially diluted to 3 times the final concentration (2×), was added. Here, the maximum final antibody concentration was 10 nm, with a total of 6 concentrations for each antibody, and 2 duplicates were set. After culturing for 3 days, the supernatant was collected and the concentration of IFN-γ was detected by ELISA. The results are shown in Figure 7. Figures 7A to 7H show that antibodies PR003248, PR003249, PR003250, PR003252, PR003259, PR003261, PR003264, PR003266 and the control antibody have high activity in promoting T cell activation and IFN-γ secretion (where A to D are from donor 1 and E to H are from donor 2). Figure 7I also shows that PR004260, PR004261, PR004262, and PR004263 also have high activity in promoting IFN-γ secretion from T cells. If artificial antigen-presenting cells do not express B7-H7, the antibody does not show activity that promotes T cell activation, suggesting that the antibody's action is specific to B7-H7 (Figure 8 shows the result that the B7-H7 antibody does not act on B7-H7-negative cells and is unable to activate T cells).

[0162] Example 6. Detection of NK cell-killing activity To detect the function of anti-B7-H7 antibody in activating NK cells, this experiment used MDA-MB-231 cells overexpressing full-length B7-H7 as target cells (MDA-MB-231 / hB7-H7, Wahaku Pharmaceutical). NK cells were isolated using a human NK cell isolation kit (Miltenyi, #130-092-657) according to the instructions in the user manual. The isolated and purified NK cells were activated with 100 IU / ml interleukin-2 for 2 days. The target cells MDA-MB-231 / hB7-H7 were digested with pancreatin and stained with the cell tracking dye CFSE 1uM for 10 minutes at room temperature in the dark. The activated NK cells were co-cultured with target cells, the B7H7 antibody was added, and incubated in a 37°C incubator for 4 hours. After incubation was complete, 2 μl of 7AAD dead cell dye was added to each well, the cells were uniformly mixed using a pipette, and the data was analyzed within 10 minutes using a BD Canto II flow cytometer to detect target cell euthanasia. (Target cell euthanasia (%) = 7AAD + CFSE + double-positive cells / CFSE + positive cells) The results are shown in Figure 9, where antibody PR004263 significantly and dose-dependently enhanced NK cell-mediated target cell killing compared to isotype controls.

[0163] Example 7. Measurement of affinity between anti-B7-H7 antibody and human B7-H7 recombinant protein. Affinity measurement using the BLI method A 10× dose of dynamic buffer (ForteBio, #18-1105) was diluted to 1× and used for affinity testing and dilution of antigens and antibodies. Dynamic analysis of antigen-antibody binding was performed using an Octet Red 96e (Fortebio) molecular interaction analyzer with biolayer interference (BLI) technology.

[0164] When measuring the affinity between antigen and antibody, the sensor rotation speed was set to 1000 revolutions per minute. First, a single row of AHC sensors (Fortebio, #18-5060) was equilibrated in the test buffer for 10 minutes. Then, B7-H7 antibody was captured with the AHC sensor, with a capture height of 0.7 nm. After equilibrating the AHC sensor in the buffer for 120 seconds, it was bound to 2-fold serially diluted human B7-H7 (with concentrations of 50-3.125 nm and 0 nm) for 180 seconds and dissociated for 300 seconds. Finally, the AHC sensor was regenerated by immersion in 10 mm of glycine-hydrochloride pH 1.5 solution to elute the protein bound to the sensor.

[0165] When analyzing data with Octet Data Analysis software (Fortebio, version 11.0), use 0nm as the reference well, remove the reference signal (reference subtraction), select the "1:1 Global fitting" method for data fitting, calculate the dynamic parameters of antigen-antigen binding, and k on (1 / Ms) value, k dis (1 / s) value and K D The (M) value was obtained. The results are shown in Table 5.

[0166] [Table 14]

[0167] Example 8. Measurement of epitope competition for binding of anti-B7-H7 antibody to B7-H7 by BLI method Epitope competition experiments were performed on B7-H7 antibody using the ForteBio Octet Red96e platform, with the same experimental buffer as above. Step 1, acquisition of 100% antibody signal: B7-H7 (Acro Biosystems, B77-H82F5) was captured using an SA sensor (Fortebio, #18-5019) with a capture height of 0.25 nm. After equilibrating the sensor in buffer for 120 s, it was subjected to 240 s with each antibody diluted to 100 nm, and the final signal of antibody-B7-H7 binding was recorded as the 100% signal of the antibody. Step 2, epitope competition experiment: B7-H7 was captured with an SA sensor with a capture height of 0.25 nm. The sensor was immersed in the first antibody (with a concentration of 100 nm) for 240 seconds, and then the SA sensor was immersed in a mixture of the first antibody and the second antibody (both antibodies having a final concentration of 100 nm) for 240 seconds. The signal difference after immersion of the sensor in the antibody mixture was recorded as the signal of the second antibody. The inhibition rate was calculated using the following formula. Inhibition rate (%) = (AB) / A * 100 A is the 100% signal of a certain antibody (obtained from step 1), B is the signal of the same antibody as a second antibody (obtained from step 2).

[0168] If the obtained inhibition rate is greater than 85%, it means that the epitopes of the two antibodies completely overlap. If the inhibition rate is less than 85%, it means that the epitopes to which the two antibodies bind do not completely overlap.

[0169] First, PR003249 was designated as the first antibody, and the other antibodies as the second antibody, and their competitiveness was detected (PR003249 in the second antibody group included three overlaps). According to the results in Table 6-1, the second antibodies PR003248, PR003250, PR003252, PR003259, PR003261, PR003264, PR003265, and PR003266 and the first antibody PR003249 completely competed with each other, suggesting they belonged to the same first binding epitope, while the control antibody PR003181 partially overlapped with them. For the remaining other different epitope antibodies, PR003251 was designated as the first antibody and the other antibodies as second antibodies, competing with it. According to the results in Table 6-2, PR003251, PR003254, PR003260, PR003262, and PR003263 completely competed, suggesting they belong to two different identical binding epitopes, while the control antibody PR003181 did not overlap with them. A summary of the epitopes for antibody binding to B7-H7 is shown in Table 6-3.

[0170] [Table 15]

[0171] [Table 16]

[0172] [Table 17]

[0173] Example 9. Cross-reactivity with other members of the B7 family Proteins from the B7 family (see Table 7 for details) were each diluted to 1 μg / mL in PBS and added to a 96-well plate (Corning, #9018) at a rate of 100 μl / well. The plate was incubated overnight at 4°C. After discarding the liquid, the plate was washed three times with PBST buffer (pH 7.4, containing 0.05% tween-20), 250 μl of 2% BSA mounting medium was added, and the plate was incubated at 37°C for 1 hour. The mounting medium was discarded, the plate was washed three times with PBST buffer (pH 7.4, containing 0.05% tween-20), the target antigen-binding protein was diluted to two concentrations (10 nm and 1 nm), 100 μl was added to each well, and the plates were incubated at 37°C for 1 hour. Isotyped antibodies were used as controls. After washing three times with PBST buffer (pH 7.4, containing 0.05% tween-20), a 5000-fold diluted sheep anti-human HRP secondary antibody (Invitrogen, #A18805) was added, and the mixture was incubated at 37°C in the dark for 1 hour. After washing three times with PBST buffer (pH 7.4, containing 0.05% tween-20), 100 μl / well of TMB (Biopanda, #TMB-S-003) was added, and the mixture was left at room temperature in the dark for approximately 30 minutes. 50 μl / well of stop solution (BBI life sciences, #E661006-0200) was added to each well to stop the reaction, and the plates were placed in a plate reader (PerkinElemer, #Enspire) to measure the absorbance at 450 nm (OD450). Figure 10 shows that the antibody of the present invention specifically binds only to the B7-H7 protein and does not cross-react with other member proteins of the B7 family.

[0174] [Table 18]

[0175] Example 10. Serum stability analysis 30 μl of antibody was taken and diluted in 270 μl of normal human serum (serum concentration 90%). The antibody was divided into 5 parts and incubated at 37°C for 0, 1, 4, 7, and 14 days respectively. The parts were removed, rapidly frozen in liquid nitrogen, and stored at -80°C. Binding of the antibody to B7-H7 in HEK-293 / hB7-H7 cells was detected by flow cytometry. HEK-293 / hB7-H7 cells were digested and resuspended in PBS containing 2% BSA. Cell density was set to 1 × 10⁶. 6 The solution was adjusted to cells / mL. 100 μL of cells / well was inoculated into a 96-well V-bottom plate (Corning, #3894), and then 100 μL / well of the target antibody, serially diluted to a 3-fold concentration (twice the final concentration), was added. The cells were incubated at 4°C for 2 hours in the dark. Then, 100 μL / well of pre-cooled 2% BSA-containing PBS was added, the cells were rinsed twice, and the mixture was centrifuged at 500 g at 4°C for 5 minutes, discarding the supernatant. Next, 100 μL / well of the fluorescent secondary antibody (Alexa Fluor 488-conjugated AffiniPure Goat Anti-Human IgG, Fcγ Fragment Specific, Jackson, #109-545-098, 1:500 dilution) was added, and the mixture was incubated at 4°C for 60 minutes in the dark. Cells were washed twice with 100 μL / well of pre-cooled 2% BSA-containing PBS, centrifuged at 500 g at 4°C for 5 minutes, and the supernatant was discarded. Finally, cells were resuspended in 200 μL / well of pre-cooled 2% BSA-containing PBS, and fluorescence signal values ​​were read using ACEA Novocyte3000 flow cytometry. The results in Figure 11 showed that PR004261, PR004262, and PR004263 exhibited excellent stability for 14 days in human serum at 37°C.

[0176] Example 11. Antitumor effect of anti-B7-H7 antibody NCG mouse reconstituted human PBMC immune system MDA-MB-231 tumor model On the day of cell inoculation, each NCG mouse was inoculated with 5 × 10⁶ MDA-MB-231 tumor cells (MDA-MB-231 / hB7-H7 cells) that overexpress human B7-H7. 6The cells were subcutaneously inoculated, then resuspended in a mixture of PBS and Matrigel (1:1) (0.1 mL / mouse) and subcutaneously inoculated again. The average tumor volume of mice was approximately 90 mm². 3 If this occurs, the mice will be divided into groups, with the 24 mice divided into 4 groups and each mouse given 5 x 10 6 Human PBMCs were inoculated intravenously, and the cells were resuspended in 200 μl of PBS. Administration was started the following day, with a dosing cycle of twice a week for a total of 4 weeks. The efficacy of PR004261, PR004262, and PR004263 antibodies at a dose of 20 MPK was tested via tail vein administration. After the start of administration, body weight and tumor volume were weighed twice a week. The formula for calculating tumor volume was: tumor volume (mm²). 3 ) = 0.5 × Tumor length × Tumor width 2 The experimental observation was concluded on the 36th day after administration, and all mice were subsequently euthanized.

[0177] For the in vivo antitumor effect of the MDA-MB-231 / hB7-H7 tumor model of the NCG mouse-reconstituted human PBMC immune system, please refer to A in Figure 12. Specifically, the vehicle control group mice had an average tumor volume of 339 mm² at day 32 after administration. 3 The group treated with the investigational drug PR004261 (20 mg / kg) had an average tumor volume of 192 mm on day 32 after administration. 3 This showed a significant difference compared to the vehicle control group (p<0.0001), with a tumor inhibition rate (TGI) of 43.43%. In the group treated with the investigational drug PR004262 (20 mg / kg), the mean tumor volume was 229 mm on day 32 after administration. 3 This showed a significant difference compared to the vehicle control group (p-value 0.0049), with a tumor inhibition rate (TGI) of 32.52%. In the group treated with the investigational drug PR004263 (20 mg / kg), the average tumor volume was 86 mm on day 32 after administration. 3 This showed a significant difference compared to the vehicle control group (p<0.0001), with a tumor inhibition rate (TGI) of 74.57%.

[0178] In the second experiment, a similar tumor inoculation plan was used, with administration twice a week for a total of three weeks. The drug was administered intraperitoneally, and the efficacy of PR004263 antibody at three doses: 5 MPK, 10 MPK, and 20 MPK was tested. After the start of administration, body weight and tumor volume were weighed twice a week. The formula for calculating tumor volume was: tumor volume (mm²). 3 ) = 0.5 × Tumor length × Tumor width 2 The experimental observation was concluded on the 36th day after administration, and all mice were subsequently euthanized.

[0179] For the in vivo antitumor effect in the tumor model, please refer to B in Figure 12. Specifically, the vehicle control group of mice had an average tumor volume of 618 mm² on day 26 after inoculation. 3 The group treated with the investigational drug PR004263 (5 mg / kg) showed an average tumor volume of 420 mm² on day 26 after vaccination. 3 This showed a significant difference compared to the vehicle control group (p<0.0198), with a tumor inhibition rate (TGI) of 32.1%. In the group treated with the investigational drug PR004263 (10 mg / kg), the average tumor volume was 243 mm² on day 26 after vaccination. 3 This showed a significant difference compared to the vehicle control group (p-value 0.0001), with a tumor inhibition rate (TGI) of 60.65%. In the group treated with the investigational drug PR004263 (20 mg / kg), the average tumor volume was 219 mm² on day 26 after vaccination. 3 This showed a significant difference compared to the vehicle control group (p<0.0001), with a tumor inhibition rate (TGI) of 64.52%.

[0180] NCG mouse reconstituted human PBMC immune system NUGC-4 tumor model and HCC-827 tumor model Both NUGC-4 and HCC-827 tumor cells endogenously express B7-H7. In vivo pharmacodynamic studies were conducted using a NUGC-4 tumor model of the NCG mouse-reconstituted human PBMC immune system. The specific method was as follows: on the day of cell inoculation, a total of 5 × 10⁶ cells were administered to each NCG mouse. 6 NUGC-4 tumor cells and 1 × 10 6 Human PBMCs were subcutaneously inoculated and mixed before subcutaneous inoculation. The average tumor volume of mice in each group was 70 mm². 3If necessary, the patients will be divided into groups and administered a total of six times, administered intraperitoneally. After the start of administration, body weight and tumor volume will be weighed twice a week, and the formula for calculating tumor volume is: tumor volume (mm 3 ) = 0.5 × Tumor length × Tumor width 2 Data analysis was performed using a t-test. For the in vivo antitumor effect of the NUGC-4 tumor model of the NCG mouse-reconstituted human PBMC immune system, please refer to C in Figure 12. Specifically, the antibody control group mice had an average tumor volume of 1140.62 mm² on day 26 after administration. 3 The group treated with the investigational drug PR004263 (10 mg / kg) had an average tumor volume of 491.38 mm² on day 26 after administration. 3 Compared to the vehicle control group, there was a significant difference (p<0.05), and the tumor inhibition rate (TGI) was 56.92%. In the 20 mg / kg treatment group, the mean tumor volume on day 26 after administration was 191.99 mm². 3 Compared to the vehicle control group, there was a significant difference (p<0.01), with a tumor inhibition rate (TGI) of 83.17%.

[0181] We conducted in vivo pharmacodynamic studies using an HCC-827 tumor model of the NCG mouse-reconstituted human PBMC immune system. The specific method was as follows: on the day of cell inoculation, 1 × 10⁶ cells were administered to each NCG mouse. 7 HCC-827 cells were subcutaneously inoculated. The average tumor volume in mice was approximately 110 mm². 3 If this occurs, the mice will be divided into groups and placed in a 5x10 grid. 6 Human PBMCs were administered intravenously, and treatment began the following day. The treatment cycle was twice a week, for a total of five doses, administered by intraperitoneal injection. After the start of treatment, body weight and tumor volume were weighed twice a week, and the formula for calculating tumor volume was: tumor volume (mm²). 3 ) = 0.5 × Tumor length × Tumor width 2 The experimental observation was completed on day 26 after administration, and all mice were subsequently euthanized. For the in vivo antitumor effect of the NCG mouse-reconstituted human PBMC immune system HCC-827 tumor model, please refer to D in Figure 12. Specifically, the antibody control group mice had an average tumor volume of 1020.74 mm² on day 26 after administration. 3The group treated with the investigational drug PR004263 (10 mg / kg) had an average tumor volume of 778.35 mm² on day 26 after administration. 3 Compared to the vehicle control group, there was a significant difference (p<0.05), and the tumor inhibition rate (TGI) was 23.75%. In the 20 mg / kg treatment group, the mean tumor volume on day 26 after administration was 597.69 mm². 3 This showed a significant difference (p<0.01) compared to the vehicle control group, with a tumor inhibition rate (TGI) of 41.45%.

Claims

1. An anti-B7-H7 antibody or its antigen-binding fragment, comprising a light chain variable region (VL) and a heavy chain variable region (VH), wherein, The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 87, 97, and 120, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 12, 34, and 66, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 82, 94, and 112, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 7, 28, and 58, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 82, 94, and 112, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 7, 37, and 58, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 82, 94, and 122, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 7, 37, and 58, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 82, 94, and 123, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 7, 37, and 58, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 82, 94, and 112, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 7, 38, and 58, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 82, 94, and 122, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 7, 38, and 58, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 82, 94, and 123, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 7, 38, and 58, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 82, 94, and 122, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 7, 28, and 58, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 82, 94, and 123, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 7, 28, and 58, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 85, 97, and 116, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 9, 27, and 63, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 85, 97, and 116, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 9, 39, and 63, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 85, 97, and 124, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 9, 39, and 63, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 85, 97, and 125, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 9, 39, and 63, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 85, 97, and 116, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 9, 40, and 63, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 85, 97, and 124, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 9, 40, and 63, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 85, 97, and 125, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 9, 40, and 63, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 85, 97, and 124, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 9, 27, and 63, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 85, 97, and 125, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 9, 27, and 63, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 81, 94, and 111, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 7, 27, and 57, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 82, 94, and 112, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 7, 28, and 59, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 83, 95, and 113, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 8, 29, and 60, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 82, 96, and 114, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 9, 27, and 61, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs: 84, 95, and 115, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs: 10, 29, and 62, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 83, 98, and 113, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 8, 30, and 62, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 82, 94, and 117, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 9, 31, and 64, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 86, 95, and 118, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 8, 32, and 62, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 83, 99, and 119, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 11, 33, and 65, respectively, or The VL comprises LCDR1, LCDR2, and LCDR3 having the amino acid sequences shown in SEQ ID NOs. 88, 100, and 121, respectively, and the VH comprises HCDR1, HCDR2, and HCDR3 having the amino acid sequences shown in SEQ ID NOs. 13, 35, and 67, respectively, or An anti-B7-H7 antibody or its antigen-binding fragment, characterized in that VL comprises LCDR1, LCDR2, and LCDR3 having amino acid sequences shown in SEQ ID NOs. 82, 94, and 111, respectively, and VH comprises HCDR1, HCDR2, and HCDR3 having amino acid sequences shown in SEQ ID NOs. 7, 36, and 68, respectively.

2. The VL comprises the amino acid sequence shown in SEQ ID NO: 161, and the VH comprises the amino acid sequence shown in SEQ ID NO: 143, or The VL comprises the amino acid sequence shown in SEQ ID NO: 152, and the VH comprises the amino acid sequence shown in SEQ ID NO: 133, or The VL comprises the amino acid sequence shown in SEQ ID NO: 152, and the VH comprises the amino acid sequence shown in SEQ ID NO: 146, or The VL comprises the amino acid sequence shown in SEQ ID NO: 164, and the VH comprises the amino acid sequence shown in SEQ ID NO: 146, or The VL comprises the amino acid sequence shown in SEQ ID NO: 165, and the VH comprises the amino acid sequence shown in SEQ ID NO: 146, or The VL comprises the amino acid sequence shown in SEQ ID NO: 152, and the VH comprises the amino acid sequence shown in SEQ ID NO: 147, or The VL comprises the amino acid sequence shown in SEQ ID NO: 164, and the VH comprises the amino acid sequence shown in SEQ ID NO: 147, or The VL comprises the amino acid sequence shown in SEQ ID NO: 165, and the VH comprises the amino acid sequence shown in SEQ ID NO: 147, or The VL comprises the amino acid sequence shown in SEQ ID NO: 164, and the VH comprises the amino acid sequence shown in SEQ ID NO: 133, or The VL comprises the amino acid sequence shown in SEQ ID NO: 165, and the VH comprises the amino acid sequence shown in SEQ ID NO: 133, or The VL comprises the amino acid sequence shown in SEQ ID NO: 156, and the VH comprises the amino acid sequence shown in SEQ ID NO: 138, or The VL comprises the amino acid sequence shown in SEQ ID NO: 156, and the VH comprises the amino acid sequence shown in SEQ ID NO: 148, or The VL comprises the amino acid sequence shown in SEQ ID NO: 166, and the VH comprises the amino acid sequence shown in SEQ ID NO: 148, or The VL comprises the amino acid sequence shown in SEQ ID NO: 167, and the VH comprises the amino acid sequence shown in SEQ ID NO: 148, or The VL comprises the amino acid sequence shown in SEQ ID NO: 156, and the VH comprises the amino acid sequence shown in SEQ ID NO: 149, or The VL comprises the amino acid sequence shown in SEQ ID NO: 166, and the VH comprises the amino acid sequence shown in SEQ ID NO: 149, or The VL comprises the amino acid sequence shown in SEQ ID NO: 167, and the VH comprises the amino acid sequence shown in SEQ ID NO: 149, or The VL comprises the amino acid sequence shown in SEQ ID NO: 166, and the VH comprises the amino acid sequence shown in SEQ ID NO: 138, or The VL comprises the amino acid sequence shown in SEQ ID NO: 167, and the VH comprises the amino acid sequence shown in SEQ ID NO: 138, or The VL comprises the amino acid sequence shown in SEQ ID NO: 151, and the VH comprises the amino acid sequence shown in SEQ ID NO: 132, or The VL comprises the amino acid sequence shown in SEQ ID NO: 152, and the VH comprises the amino acid sequence shown in SEQ ID NO: 134, or The VL comprises the amino acid sequence shown in SEQ ID NO: 153, and the VH comprises the amino acid sequence shown in SEQ ID NO: 135, or The VL comprises the amino acid sequence shown in SEQ ID NO: 154, and the VH comprises the amino acid sequence shown in SEQ ID NO: 136, or The VL comprises the amino acid sequence shown in SEQ ID NO: 155, and the VH comprises the amino acid sequence shown in SEQ ID NO: 137, or The VL comprises the amino acid sequence shown in SEQ ID NO: 157, and the VH comprises the amino acid sequence shown in SEQ ID NO: 139, or The VL comprises the amino acid sequence shown in SEQ ID NO: 158, and the VH comprises the amino acid sequence shown in SEQ ID NO: 140, or The VL comprises the amino acid sequence shown in SEQ ID NO: 159, and the VH comprises the amino acid sequence shown in SEQ ID NO: 141, or The VL comprises the amino acid sequence shown in SEQ ID NO: 160, and the VH comprises the amino acid sequence shown in SEQ ID NO: 142, or The VL comprises the amino acid sequence shown in SEQ ID NO: 162, and the VH comprises the amino acid sequence shown in SEQ ID NO: 144, or The anti-B7-H7 antibody or antigen-binding fragment thereof according to claim 1, wherein VL comprises the amino acid sequence shown in SEQ ID NO: 163, and VH comprises the amino acid sequence shown in SEQ ID NO:

145.

3. Full-length antibody, Fab, Fab', F(ab') ２ The anti-B7-H7 antibody or antigen-binding fragment thereof according to claim 1, which is Fv, scFv, a bispecific antibody, a multispecific antibody, or a monoclonal antibody.

4. This is a full-length antibody containing both a constant region of the antibody heavy chain and a constant region of the antibody light chain. The heavy chain constant region is selected from IgG1, IgG2, IgG3, or IgG4, and / or the light chain constant region is selected from the κ chain or λ chain of a human antibody. The anti-B7-H7 antibody or its antigen-binding fragment according to claim 3.

5. The full-length antibody comprises a heavy chain and a light chain, where, The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 186, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 202, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 180, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 202, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 184, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 193, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 170, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 193, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 187, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 193, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 187, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 205, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 187, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 206, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 188, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 193, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 188, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 205, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 188, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 206, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 184, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 205, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 184, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 206, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 185, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 197, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 175, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 197, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 189, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 197, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 189, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 207, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 189, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 208, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 190, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 197, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 190, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 207, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 190, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 208, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 185, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 207, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 185, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 208, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 169, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 192, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 171, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 193, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 172, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 194, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 173, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 195, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 174, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 196, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 176, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 198, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 177, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 199, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 178, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 200, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 179, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 201, or The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 181, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 203, or The anti-B7-H7 antibody or antigen-binding fragment thereof according to claim 4, wherein the heavy chain comprises the amino acid sequence shown in SEQ ID NO: 182, and the light chain comprises the amino acid sequence shown in SEQ ID NO:

204.

6. An isolated nucleic acid encoding an anti-B7-H7 antibody or an antigen-binding fragment thereof according to any one of claims 1 to 5.

7. A recombinant expression vector comprising the isolated nucleic acid described in claim 6.

8. A transformant comprising the recombinant expression vector described in claim 7.

9. A chimeric antigen receptor comprising the anti-B7-H7 antibody or its antigen-binding fragment as described in claim 1.

10. Genetically modified cells comprising the chimeric antigen receptor described in claim 9.

11. A genetically modified cell according to claim 10, which is an immune cell.

12. A method for producing an anti-B7-H7 antibody or an antigen-binding fragment thereof, the method comprising the step of culturing the transformant described in claim 8 and obtaining an anti-B7-H7 antibody or an antigen-binding fragment thereof from the culture.

13. An antibody-drug conjugate comprising an antibody portion and a conjugate portion, wherein the antibody portion comprises the anti-B7-H7 antibody described in claim 1 or an antigen-binding fragment thereof, the conjugate portion comprises a detectable marker, drug, toxin, cytokine, radionuclide, enzyme, or a combination thereof, and the antibody portion and the conjugate portion are conjugated via a chemical bond or a linker.

14. A composition comprising an anti-B7-H7 antibody or its antigen-binding fragment according to any one of claims 1 to 5, a chimeric antigen receptor according to claim 9, a gene-modified cell according to any one of claims 10 to 11, and / or an antibody-drug conjugate according to claim 13.

15. The composition according to claim 14, further comprising a combination therapy agent, wherein the combination therapy agent comprises a chemotherapeutic agent, a radiotherapy agent, an immunosuppressant, and / or a cytotoxic drug.

16. A kit comprising an antibody or antigen-binding fragment thereof according to any one of claims 1 to 5, a chimeric antigen receptor according to claim 9, a gene-modified cell according to any one of claims 10 to 11, and / or an antibody-drug conjugate according to claim 13.

17. (i) a device for administering the antibody or its antigen-binding fragment or the chimeric antigen receptor or the gene-modified cell or the antibody-drug conjugate, and / or (ii) an instruction manual, further comprising the kit according to claim 16.

18. A pharmaceutical composition for treating and / or preventing cancer, comprising an anti-B7-H7 antibody or its antigen-binding fragment according to any one of claims 1 to 5, a chimeric antigen receptor according to claim 9, a gene-modified cell according to any one of claims 10 to 11, and / or an antibody-drug conjugate according to claim 13.

19. The pharmaceutical composition according to claim 18, wherein the cancer is selected from the group consisting of lung cancer, breast cancer, gastric cancer, small intestine cancer, colon cancer, rectal cancer, pancreatic cancer, kidney cancer, bladder cancer, and osteosarcoma.

20. An administration device comprising an anti-B7-H7 antibody or its antigen-binding fragment according to any one of claims 1 to 5, a chimeric antigen receptor according to claim 9, a gene-modified cell according to any one of claims 10 to 11, and / or an antibody-drug conjugate according to claim 13.

21. The administration device according to claim 20, further comprising a syringe, injection device, or implantable administration device for containing or administering to a subject the anti-B7-H7 antibody or its antigen-binding fragment, the chimeric antigen receptor, the genetically modified cells, and / or the antibody-drug conjugate.

22. A method for detecting B7-H7, comprising the step of detecting it using an anti-B7-H7 antibody or an antigen-binding fragment thereof as described in any one of claims 1 to 5, a chimeric antigen receptor as described in claim 9, a genetically modified cell as described in any one of claims 10 to 11, and / or an antibody-drug conjugate as described in claim 13, wherein the detection is not for the purpose of diagnosis and / or treatment.

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