High-affinity b7h7 antibody or antigen-binding fragment thereof and use thereof

Abstract

The invention provides a high-affinity B7H7 antibody or an antigen binding fragment thereof and application thereof, and relates to the field of antibodies. Wherein the antibody or the antigen binding fragment thereof comprises a heavy chain complementarity determining region HCDR and a light chain complementarity determining region LCDR, and the HCDR comprises at least one selected from SEQ ID NO: 1-3 or an amino acid sequence having at least 80% homology with the HCDR; the LCDR comprises at least one of SEQ ID NO: 4-6 or an amino acid sequence having at least 80% homology with the at least one of SEQ ID NO: 4-6. The antibody or the antigen binding fragment has high specificity and high affinity, can bind to human and cynomolgus monkey B7H7, specifically blocks binding of B7H7 and its receptor KIR3DL3, promotes killing of immune cells to tumor cells, and effectively treats and / or prevents B7H7-mediated related diseases, such as tumors.

Description

(19) State Intellectual Property Office (12) Invention Patent Application (10) Application Publication Number (43) Application Publication Date (21) Application Number 202410656861.9 (22) Application Date 2024.05.24 (71) Applicant Hefei Tiangang Immunotherapy Co., Ltd. Address 2001, 2nd Floor, Building 1, Hefei Innovation and Entrepreneurship Park, No. 268 Furong Road, Economic and Technological Development Zone, Hefei City, Anhui Province, 230001 (72) Inventors Li Yangyang, Cao Guoshuai, Cheng Ying, Wu Yuwei (74) Patent Agency Beijing Qingyihua Intellectual Property Agency (General Partnership) 11201 Patent Attorney Zhang Wei (51) Int.Cl. C07K 16 / 28 (2006.01) A61K 39 / 395 (2006.01) A61K 47 / 68 (2017.01) A61P 35 / 00(2006.01) A61P 35 / 02(2006.01) G01N 33 / 574(2006.01) G01N 33 / 577(2006.01) (54) Invention Title: High Affinity B7H7 Antibody or Antigen-Binding Fragment thereof and Its Use (57) Abstract: This application discloses a high affinity B7H7 antibody or its antigen-binding fragment thereof and its use, relating to the field of antibodies. The aforementioned antibody or its antigen-binding fragment comprises: a heavy chain complementarity-determining region (HCDR) and a light chain complementarity-determining region (LCDR), wherein the HCDR contains an amino acid sequence selected from at least one of SEQ ID NO:1-3 or having at least 80% homology with it; and the LCDR contains an amino acid sequence selected from at least one of SEQ ID NO:4-6 or having at least 80% homology with it. The aforementioned antibody or antigen-binding fragment has high specificity and high affinity, and can bind to human and cynomolgus monkey B7H7, and specifically block the binding of B7H7 to its receptor KIR3DL3, promoting the killing of tumor cells by immune cells, and effectively treating and / or preventing B7H7-mediated related diseases, such as tumors. Claims 3 pages, Description 16 pages, Sequence Listing (electronic publication), Drawings 2 pages. CN 121005781 A 2025.11.25 CN 1 21 00 57 81 A 1. An antibody or its antigen-binding fragment, characterized in that it comprises: a heavy chain complementarity-determining region (HCDR) and a light chain complementarity-determining region (LCDR); wherein, the HCDR comprises at least one of SEQ ID NO:1-3 or an amino acid sequence having at least 80% homology thereto; the LCDR comprises at least one of SEQ ID NO:4-6 or an amino acid sequence having at least 80% homology thereto. 2. The antibody or its antigen-binding fragment according to claim 1, characterized in that, the HCDR comprises: HCDR1,HCDR2 and HCDR3, wherein: HCDR1 comprises an amino acid sequence as shown in SEQ ID NO:1 or having at least 80% homology with SEQ ID NO:1; HCDR2 comprises an amino acid sequence as shown in SEQ ID NO:2 or having at least 80% homology with SEQ ID NO:2; and HCDR3 comprises an amino acid sequence selected from those shown in SEQ ID NO:3 or having at least 80% homology with SEQ ID NO:3; preferably, the HCDR comprises: HCDR1 with an amino acid sequence as shown in SEQ ID NO:1; preferably, the HCDR comprises: HCDR2 with an amino acid sequence as shown in SEQ ID NO:2; preferably, the HCDR comprises: HCDR3 with an amino acid sequence as shown in SEQ ID NO:3. 3. The antibody or antigen-binding fragment thereof according to claim 1, characterized in that the LCDR comprises: LCDR1, LCDR2 and LCDR3, wherein: LCDR1 comprises an amino acid sequence as shown in SEQ ID NO:4 or having at least 80% homology with SEQ ID NO:4; LCDR2 comprises an amino acid sequence as shown in SEQ ID NO:5 or having at least 80% homology with SEQ ID NO:5; and LCDR3 comprises an amino acid sequence as shown in SEQ ID NO:6 or having at least 80% homology with SEQ ID NO:6; preferably, the LCDR comprises: LCDR1 with an amino acid sequence as shown in SEQ ID NO:4; preferably, the LCDR comprises: LCDR2 with an amino acid sequence as shown in SEQ ID NO:5; preferably, the LCDR comprises: LCDR3 with an amino acid sequence as shown in SEQ ID NO:6. 4. The antibody or antigen-binding fragment thereof according to claim 2 or 3, characterized in that the antibody or antigen-binding fragment thereof further comprises: a heavy chain framework region; optionally, the antibody or antigen-binding fragment thereof further comprises: a light chain framework region; optionally, at least a portion of the heavy chain framework region and the light chain framework region are independently derived from at least one of rabbit-derived antibodies, mouse-derived antibodies, sheep-derived antibodies, goat-derived antibodies, primate-derived antibodies or mutants thereof; preferably, the heavy chain variable region of the antibody or antigen-binding fragment thereof comprises an amino acid sequence selected from or having at least 80% homology with SEQ ID NO:7; preferably, the amino acid sequence of the heavy chain variable region of the antibody or antigen-binding fragment thereof is as shown in SEQ ID NO:7; preferably, the light chain variable region of the antibody or antigen-binding fragment thereof comprises an amino acid sequence selected from or having at least 80% homology with SEQ ID NO:7;NO:8 has an amino acid sequence with at least 80% homology; preferably, the light chain of the antibody or its antigen-binding fragment may have a variable region amino acid sequence as shown in SEQ ID NO:8. (Claim 1 / 3 page 2 CN 121005781 A) 5. The antibody or antigen-binding fragment thereof according to claim 4, characterized in that the antibody or antigen-binding fragment thereof further comprises: a heavy chain constant region; optionally, the antibody or antigen-binding fragment thereof further comprises: a light chain constant region; optionally, at least a portion of the heavy chain constant region and the light chain constant region are independently derived from at least one of rabbit-derived antibodies, mouse-derived antibodies, sheep-derived antibodies, goat-derived antibodies, primate-derived antibodies or mutants thereof; preferably, at least a portion of the heavy chain constant region and the light chain constant region are derived from human antibodies; preferably, the heavy chain constant region is selected from the human IgG1 constant region; more preferably, the human IgG1 constant region has an L234A / L235A mutation; preferably, the light chain constant region is selected from the human Ig kappa constant region; preferably, the heavy chain of the antibody or antigen-binding fragment thereof comprises an amino acid sequence selected from or having at least 80% homology with SEQ ID NO:9; preferably, the amino acid sequence of the heavy chain of the antibody or antigen-binding fragment thereof is as shown in SEQ ID NO:9; Preferably, the light chain of the antibody or its antigen-binding fragment comprises an amino acid sequence selected from or having at least 80% homology with SEQ ID NO:10; preferably, the amino acid sequence of the light chain of the antibody or its antigen-binding fragment is as shown in SEQ ID NO:10. 6. The antibody or its antigen-binding fragment according to claim 1, characterized in that the antibody comprises at least one selected from polyclonal antibodies and monoclonal antibodies; or the antigen-binding fragment comprises at least one selected from F(ab')2 fragment, Fab' fragment, Fab fragment, F(ab)2 fragment, Fv fragment, scFv fragment, scFv-Fc fusion protein, scFv-Fv fusion protein and minimum recognition unit; preferably, the antibody is a monoclonal antibody. 7. A nucleic acid molecule, characterized in that the nucleic acid molecule encodes the antibody or its antigen-binding fragment according to any one of claims 1 to 6; optionally, the nucleic acid molecule is DNA. 8. An expression vector, characterized in that it carries the nucleic acid molecule according to claim 7. 9. A method for preparing the antibody or antigen-binding fragment thereof according to any one of claims 1 to 6, characterized in that it comprises: introducing the expression vector according to claim 8 into a cell; culturing the cell under conditions suitable for protein expression and secretion to obtain the antibody or antigen-binding fragment thereof; optionally, the cell is a eukaryotic cell.10. A recombinant cell, characterized in that the recombinant cell carries the nucleic acid molecule of claim 7 or the expression vector of claim 8. 11. An immunoconjugate, characterized in that it comprises: an antibody or antigen-binding fragment thereof of any one of claims 1-6, the nucleic acid molecule of claim 7, the expression vector of claim 8, or the recombinant cell of claim 10; optionally, the immunoconjugate further comprises a therapeutic agent. 12. A composition, characterized in that it comprises: an antibody or antigen-binding fragment thereof of any one of claims 1-6, a nucleic acid molecule carrying the nucleic acid molecule of claim 7, the expression vector of claim 8, the recombinant cell of claim 10, or the immunoconjugate of claim 11. 13. Use of the antibody or antigen-binding fragment thereof of any one of claims 1-6, the nucleic acid molecule carrying the nucleic acid molecule of claim 7, the expression vector of claim 8, the recombinant cell of claim 10, the immunoconjugate of claim 11, or the composition of claim 12 in the preparation of a medicament for treating or preventing B7H7-mediated diseases. 14. The use according to claim 13, wherein the B7H7-mediated related diseases include tumors; optionally, the tumors include at least one of head and neck cancer, glioma, thyroid cancer, lung cancer, colorectal cancer, gastric cancer, liver cancer, bile duct cancer, breast cancer, ovarian cancer, endometrial cancer, kidney cancer, prostate cancer, bladder cancer, pancreatic cancer, melanoma, multiple myeloma, and acute myeloid leukemia. 15. A medicament, characterized in that it comprises: an antibody or antigen-binding fragment thereof according to any one of claims 1 to 6, a nucleic acid molecule carrying the nucleic acid molecule according to claim 7, an expression vector according to claim 8, a recombinant cell according to claim 10, an immunoconjugate according to claim 11, or a composition according to claim 12, wherein the medicament is used for or to prevent B7H7-mediated related diseases. 16. The medicament according to claim 15, wherein the B7H7-mediated related diseases include tumors; optionally, the tumors include at least one of head and neck cancer, glioma, thyroid cancer, lung cancer, colorectal cancer, gastric cancer, liver cancer, bile duct cancer, breast cancer, ovarian cancer, endometrial cancer, kidney cancer, prostate cancer, bladder cancer, pancreatic cancer, melanoma, multiple myeloma, and acute myeloid leukemia; optionally, further comprising pharmaceutically acceptable excipients; optionally, the excipients include: one or more pharmaceutically acceptable excipients, diluents, stabilizers, or carriers; optionally, the medicament is an injectable preparation. 17. Use of the antibody or antigen-binding fragment thereof according to any one of claims 1 to 6 in the preparation of a kit for detecting B7H7.18. A kit, characterized in that the kit comprises: an antibody or antigen-binding fragment thereof as described in any one of claims 1 to 6. 19. The kit according to claim 18, characterized in that the kit is used to detect B7H7. Claims 3 / 3 Page 4 CN 121005781 A High-affinity B7H7 antibody or antigen-binding fragment thereof and its use Technical Field

[0001] This application belongs to the field of antibodies, specifically relating to a high-affinity B7H7 antibody or antigen-binding fragment thereof and its use. Background Art

[0002] In recent years, anti-tumor immunotherapy targeting immune checkpoints has achieved great success in clinical applications. Highly representative multi-personalized or fully human monoclonal antibodies targeting CTLA-4 and PD-1 / PD-L1 have been approved for marketing and use in the treatment of various tumors. Nevertheless, the overall patient response rate is only 30%, and a large number of clinical patients still cannot benefit. Therefore, it is necessary to find new immune checkpoint molecules and new combination therapy strategies.

[0003] B7H7, also known as HHLA2, is a type I transmembrane protein composed of three extracellular Ig-like domains, a transmembrane region, and a cytoplasmic tail of 49 amino acids with no recognizable tone. B7H7 is a member of the B7 family and shares about 20%-30% similarity with other members of the B7 family. In normal tissues, B7-H7 is mainly expressed in the gastrointestinal tract, bile ducts, etc., and is not expressed in other normal tissues. However, in many types of tumors, such as breast cancer, lung cancer, colorectal cancer, and pancreatic cancer, B7H7 is highly expressed and is negatively correlated with patient prognosis.

[0004] Studies have reported that B7H7 can bind to its receptor KIR3DL3, thereby inhibiting the effector function of NK cells and T cells. Blocking the binding of B7H7 to KIR3DL3 with blocking antibodies can significantly restore the anti-tumor function of NK cells and T cells. Therefore, targeting the B7H7-KIR3DL3 signaling pathway is very promising.

[0005] Currently, there are relatively few clinical studies on B7H7, with only Harbour BioMed's HBM1020 in Phase I clinical trials. Therefore, there is an urgent need to develop a high-affinity therapeutic anti-B7H7 antibody. Summary of the Invention

[0006] This application is based on the inventors' findings regarding the following issues and facts:

[0007] B7H7 is mainly expressed in the gastrointestinal tract, bile ducts, and other tissues, but not in other normal tissues. However, in many tumor types, such as breast cancer, lung cancer, colorectal cancer, and pancreatic cancer, B7H7 is highly expressed and negatively correlated with patient prognosis.

[0008] Previous studies have reported that B7H7 can bind to its receptor KIR3DL3, thereby inhibiting the effects of NK cells and T cells.Function. By blocking the binding of B7H7 to KIR3DL3 with blocking antibodies, the anti-tumor function of NK cells and T cells can be significantly restored.

[0009] The inventors of this application obtained a high-affinity humanized anti-B7H7 antibody through affinity maturation modification. The inventors found that the high-affinity humanized anti-B7H7 antibody obtained in this application can specifically target and bind to B7H7, block the binding of B7H7 to its receptor KIR3DL3, promote the killing of tumor cells by immune cells, and thus effectively treat and / or prevent B7H7-mediated related diseases, such as tumors.

[0010] Specifically, this application provides the following technical solution:

[0011] In a first aspect of this application, this application proposes an antibody or its antigen-binding fragment. According to embodiments of this application, it includes: a heavy chain complementarity-determining region (HCDR) and a light chain complementarity-determining region (LCDR); wherein the HCDR comprises an amino acid sequence selected from at least one of SEQ ID NO: 1-3 or having at least 80% homology with it; the LCDR comprises an amino acid sequence selected from at least one of SEQ ID NO: 4-6 or having at least 80% homology with it. In some examples of this application, the aforementioned antibody or antigen-binding fragment has high specificity and high affinity, and can bind to human and cynomolgus monkey B7H7, and specifically block the binding of B7H7 to its receptor KIR3DL3, promote the killing of tumor cells by immune cells, and effectively treat and / or prevent B7H7-mediated related diseases, such as tumors.

[0012] In a second aspect of this application, this application proposes a nucleic acid molecule. According to embodiments of this application, the nucleic acid molecule encodes the antibody or antigen-binding fragment described in the first aspect of this application. In some examples of this application, the aforementioned nucleic acid molecule enables the large-scale preparation of the aforementioned antibody or antigen-binding fragment in vitro.

[0013] In a third aspect of this application, an expression vector is provided. According to an embodiment of this application, the expression vector carries the nucleic acid molecule described in the second aspect of this application. In some examples of this application, the expression vector can efficiently express the aforementioned antibody or its antigen-binding fragment in suitable host cells.

[0014] In a fourth aspect of this application, a method for preparing the antibody or its antigen-binding fragment described in the first aspect is provided. According to an embodiment of this application, the method includes: introducing the expression vector described in the third aspect of this application into a cell; culturing the cell under conditions suitable for protein expression and secretion to obtain the antibody or its antigen-binding fragment. In some examples of this application, the aforementioned method can efficiently prepare the aforementioned antibody or its antigen-binding fragment.

[0015] In a fifth aspect of this application, a recombinant cell is provided. According to an embodiment of this application, the recombinant cell...The recombinant cells carry the antibody or its antigen-binding fragment described in the first aspect of this application, the nucleic acid molecule described in the second aspect, or the expression vector described in the third aspect. The recombinant cells are obtained by transfection or transformation of the expression vector. In some examples of this application, the recombinant cells can efficiently express the aforementioned antibody or its antigen-binding fragment under suitable conditions.

[0016] In a sixth aspect of this application, an immunoconjugate is proposed. According to embodiments of this application, the immunoconjugate comprises: the antibody or its antigen-binding fragment described in the first aspect of this application, the nucleic acid molecule described in the second aspect, the expression vector described in the third aspect, or the recombinant cells described in the fifth aspect. As previously stated, the antibody or antigen-binding fragment can effectively bind specifically to human and cynomolgus monkey B7H7 proteins. Therefore, immunoconjugates containing the antibody or antigen-binding fragment can also bind to the B7H7 protein in humans and cynomolgus monkeys. These immunoconjugates have good preventative and / or therapeutic effects on B7H7-mediated tumor diseases, such as head and neck cancer, glioma, thyroid cancer, lung cancer, colorectal cancer, gastric cancer, liver cancer, bile duct cancer, breast cancer, ovarian cancer, endometrial cancer, kidney cancer, prostate cancer, bladder cancer, pancreatic cancer, melanoma, multiple myeloma, and acute myeloid leukemia.

[0017] In a seventh aspect of this application, a composition is proposed. According to embodiments of this application, the composition comprises: the antibody or antigen-binding fragment described in the first aspect of the application, the nucleic acid molecule described in the second aspect, the expression vector described in the third aspect, the recombinant cell described in the fifth aspect, or the immunoconjugate described in the sixth aspect. As previously stated, the antibody or its antigen-binding fragment can effectively bind to B7H7 in humans and cynomolgus monkeys. Therefore, compositions containing the antibody or its antigen-binding fragment, such as food compositions and pharmaceutical compositions, can also effectively treat or prevent tumor diseases, such as head and neck cancer, glioma, thyroid cancer, lung cancer, colorectal cancer, gastric cancer, liver cancer, bile duct cancer, breast cancer, ovarian cancer, endometrial cancer, kidney cancer, prostate cancer, bladder cancer, pancreatic cancer, melanoma, multiple myeloma, and acute myeloid leukemia.

[0018] In an eighth aspect of this application, this application proposes the use of the antibody or its antigen-binding fragment described in the first aspect, the nucleic acid molecule described in the second aspect, the expression vector described in the third aspect, the recombinant cell described in the fifth aspect, the immunoconjugate described in the sixth aspect, or the composition described in the seventh aspect in the preparation of a medicament for the treatment or prevention of B7H7-mediated diseases. As previously stated, this antibody or its antigen-binding fragment can effectively bind to human and cynomolgus monkey B7H7. Therefore, drugs containing the antibody or its antigen-binding fragment and a series of other substances also have significant therapeutic and / or product information 2 / 16 page 6 CN 121005781 AThe drug has the effect of preventing B7H7-mediated tumor diseases (such as head and neck cancer, glioma, thyroid cancer, lung cancer, colorectal cancer, gastric cancer, liver cancer, bile duct cancer, breast cancer, ovarian cancer, endometrial cancer, kidney cancer, prostate cancer, bladder cancer, pancreatic cancer, melanoma, multiple myeloma, and acute myeloid leukemia).

[0019] In a ninth aspect of this application, this application proposes a medicament. According to an embodiment of this application, the medicament comprises: the antibody or its antigen-binding fragment described in the first aspect, the nucleic acid molecule described in the second aspect, the expression vector described in the third aspect, the recombinant cell described in the fifth aspect, the immunoconjugate described in the sixth aspect, or the composition described in the seventh aspect, the medicament being used to treat or prevent B7H7-mediated related diseases. As previously stated, the antibody or its antigen-binding fragment is effectively bound to human and cynomolgus monkey B7H7. Therefore, drugs containing the antibody or its antigen-binding fragment and a series of other substances also have significant therapeutic and / or preventive effects against B7H7-mediated tumor diseases (e.g., head and neck cancer, glioma, thyroid cancer, lung cancer, colorectal cancer, gastric cancer, liver cancer, bile duct cancer, breast cancer, ovarian cancer, endometrial cancer, kidney cancer, prostate cancer, bladder cancer, pancreatic cancer, melanoma, multiple myeloma, and acute myeloid leukemia).

[0020] In a tenth aspect of this application, the use of the antibody or its antigen-binding fragment described in the first aspect in the preparation of a kit for detecting B7H7 is provided. As previously stated, the antibody or its antigen-binding fragment can effectively bind to human and cynomolgus monkey B7H7; therefore, a kit containing the antibody or its antigen-binding fragment can be used for the effective detection of B7H7. In some examples of this application, the aforementioned kit can be used for scientific research, such as qualitative or quantitative detection of B7H7 protein in biological samples.

[0021] In an eleventh aspect of this application, a kit is provided. According to an embodiment of this application, the kit contains the antibody or its antigen-binding fragment described in the first aspect. As previously mentioned, the antibody or its antigen-binding fragment can effectively bind to human and cynomolgus monkey B7H7. Therefore, the kit containing the antibody or its antigen-binding fragment can be used to effectively detect B7H7. In some examples of this application, the kit can be used for scientific research, such as qualitative or quantitative detection of B7H7 protein in biological samples, and can also be used to determine the status of an individual, such as determining whether the individual's B7H7 level is higher or lower than normal after obtaining the individual's B7H7 level.

[0022] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Brief Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of this application, and are not applicable to this application.For those skilled in the art, other figures can be obtained from these figures without creative effort.

[0024] Figure 1 is a schematic diagram of the ELISA results of humanized antibody binding to human and cynomolgus monkey B7H7 protein provided in the embodiments of this application;

[0025] Figure 2 is a schematic diagram of the flow cytometry results of humanized antibody binding to HCC827 cell line overexpressing B7H7 provided in the embodiments of this application;

[0026] Figure 3 is a schematic diagram of the ELISA results of humanized antibody blocking the binding of B7H7 protein to KIR3DL3 protein provided in the embodiments of this application;

[0027] Figure 4 is a schematic diagram of the flow cytometry results of humanized antibody blocking the binding of B7H7 protein to CHO-K1-KIR3DL3 cells provided in the embodiments of this application;

[0028] Figure 5 is a schematic diagram of the flow cytometry results of humanized antibody promoting PBMC killing of K562 cells overexpressing B7H7 provided in the embodiments of this application. Detailed Description of Embodiments

[0029] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present application.

[0030] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] In this application, the term "antibody" refers to an immunoglobulin, which is a tetrapeptide chain structure composed of two identical heavy chains and two identical light chains linked by interchain disulfide bonds. The amino acid composition and sequence of the constant region of the immunoglobulin heavy chain are different, and therefore their antigenicity is also different. Immunoglobulins can be divided into five classes, namely IgM, IgD, IgG, IgA, and IgE. Immunoglobulins of the same class can also be divided into different subclasses according to their amino acid composition, such as IgG1, IgG2, IgG3, and IgG4. Immunoglobulin light chains are divided into κ chains or λ chains according to their constant regions.

[0032] In this application, the term "antibody affinity maturation" refers to an antibody obtained by mutating one or more CDR sequences of an antibody. In some examples of this application, affinity maturation is performed on antibody h17H7B8 (application number: 202311708700.1) to obtain antibodies with higher affinity.

[0033] In this application, the variable region of the antibody heavy chain may further include a heavy chain constant region, which contains human IgG1, IgG2, IgG3, IgG4, or variants thereof.

[0034] In this application, the antibody light chain variable region may further include a light chain constant region, wherein the light chain constant region comprises human κ, λ chains or variants thereof.

[0035] The sequence of approximately 110 amino acids near the N-terminus of the antibody heavy and light chains varies considerably and is called the variable region (Fv region); the remaining amino acid sequence near the C-terminus is relatively stable and is called the constant region. The variable region includes 3 hypervariable regions (HVR) and 4 relatively conserved backbone regions (FR). The 3 hypervariable regions determine the specificity of the antibody and are also called complementarity-determining regions (CDR). Each light chain variable region (LCVR) and heavy chain variable region (HCVR) consists of 3 CDR regions and 4 FR regions, arranged in the following order from the amino terminus to the carboxyl terminus: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. The three CDR regions of the light chain refer to LCDR1, LCDR2, and LCDR3; the three CDR regions of the heavy chain refer to HCDR1, HCDR2, and HCDR3.

[0036] In this application, the term "humanized antibody" refers to an antibody or antibody fragment obtained by replacing all or part of the CDR regions of a human immunoglobulin (receptor antibody) with the CDR regions of a non-human antibody (donor antibody), wherein the donor antibody can be a non-human antibody (e.g., mouse, rat, or rabbit) with the expected specificity, affinity, or reactivity. In addition, some amino acid residues of the framework region (FR) of the receptor antibody may also be replaced by amino acid residues of the corresponding non-human antibody, or by amino acid residues of other antibodies, to further improve or optimize the performance of the antibody.

[0037] In this application, the term "antigen-binding fragment" refers to Fab fragments, Fab' fragments, F(ab')2 fragments, and Fv fragments ScFv fragments that bind to human B7H7, which contain one or more CDR regions selected from SEQ ID NO:1 to SEQ ID NO:6 of the antibody described in this application. The Fv fragment contains variable regions of the antibody heavy chain and variable regions of the light chain, but no constant regions, and is the smallest antibody fragment with all antigen-binding sites. Generally, Fv antibodies also contain a polypeptide linker between the VH and VL domains and are capable of forming the structure required for antigen binding. Two antibody variable regions can also be linked into a single polypeptide chain using different linkers, referred to as a single-chain antibody or single-chain Fv.

[0038] In this application, the amino acid sequences of the listed CDRs are all shown according to the Kabat definition rules. However, as is known to those skilled in the art, the CDR of an antibody can be defined in various ways, such as the IMGT rule, the Chothia rule, etc. Those skilled in the art will understand that, unless otherwise specified, the terminology refers to an antibody or a region thereof (e.g., a variable region).The terms "CDR" and "complementarity determination region" should be understood to encompass the complementarity determination region defined in any of the known schemes described above by way of the present invention. Although the scope of protection claimed in this application is based on the sequence defined by the Kabat definition rules, amino acid sequences corresponding to other CDR definition rules should also be included in the scope of protection of this application.

[0039] In this application, the term "amino acid" is represented by a single-letter or three-letter code, which has the following meanings: A: Ala (alanine); R: Arg (arginine); N: Asn (asparagine); D: Aspartic acid (aspartic acid); C: Cys (cysteine); Q: Gln (glutamine); E: Glu (glutamic acid); G: Gly (glycine); H: Histidine; I: Ile (isoleucine); L: Leu (leucine); K: Lysine (lysine); M: Met (methionine); F: Phe (phenylalanine); P: Pro (proline); S: Serine (serine); T: Threonine (threonine); W: Tryptophan (tryptophan); Y: Tyr (tyrosine); V: Val (valine).

[0040] For nucleotides, the terms “homology,” “identity,” or “similarity” are used to describe or compare the degree of nucleotide similarity between two or more nucleotide sequences. The percentage of “sequence homology” between a first and a second sequence can be calculated by dividing [the number of nucleotides in the first sequence that are identical to the nucleotides at the corresponding positions] by [the number of nucleotides in the second sequence]. This is calculated by subtracting [the total number of nucleotides in the first sequence] from [the number of nucleotides in the second sequence] and then multiplying by [100%], where each deletion, insertion, substitution, or addition of a nucleotide in the second nucleotide sequence—relative to the first nucleotide sequence—is considered a difference at a single nucleotide (position). Alternatively, the degree of sequence identity between two or more nucleotide sequences can be calculated using standard settings and known computer algorithms for sequence alignment, such as NCBI Blast v2.0. Other techniques, computer algorithms, and settings used to determine the degree of sequence identity are, for example, in WO 04 / 037999, EP 0 967 284, EP 1 085 089, WO 00 / 55318, WO 00 / 78972, WO 98 / 49185, and GB 2357768-A.

[0041] For polypeptides, the terms “(substantial) homology,” “identity,” or “similarity” are used to describe or compare the degree of amino acid similarity between two or more polypeptides or their designated sequences at optimal alignment and comparison (where appropriate insertions or deletions of nucleotides are made). The homology % between two sequences varies with the number of identical positions shared by these sequences at optimal alignment (i.e., homology % = number of identical positions / total number of positions × 100), where optimal alignment takes into account the number of identical positions shared by the two sequences at optimal alignment.The optimal alignment requires the number of gaps introduced and the length of each gap to be determined. Sequence comparison and identity percentage determination between two sequences can be performed using mathematical algorithms, as described in the non-limiting embodiments below.

[0042] In this application, without substantially affecting antibody activity (retaining at least 95% activity), those skilled in the art can substitute, add, and / or delete one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more) amino acids to obtain variations of the antibody or its functional fragment sequence. These are all considered to be included within the scope of protection of this invention. For example, amino acids with similar properties can be substituted in the variable region. The variant sequences described in this application can have at least 80% identity (or homology) with the reference sequences, meaning at least 80% identity with each reference sequence, which can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 99.9%. The sequence identity described in this application can be measured using sequence analysis software. For example, using the computer program BLAST with default parameters, especially BLASTP or TBLASTN. The amino acid sequences mentioned in this invention are shown in N-terminus to C-terminus.

[0043] In this application, the term "specific binding" refers to a non-random binding reaction between two molecules, such as the reaction between an antibody and its targeted antigen. In some embodiments, an antibody that specifically binds to an antigen (or an antibody that is specific to an antigen) means that the antibody binds to the antigen with an affinity (KD) of less than about 10⁻⁵ M, for example less than about 10⁻⁶ M, 10⁻⁷ M, 10⁻⁸ M, 10⁻⁹ M, or 10⁻¹⁰ M or less.

[0044] In this application, the term “KD” refers to the dissociation equilibrium constant of a particular antibody-antigen interaction, which is used to describe the binding affinity between an antibody and an antigen. The smaller the equilibrium dissociation constant, the tighter the antibody-antigen binding and the higher the affinity between the antibody and the antigen. Typically, the antibody binds to the antigen with an affinity (KD) of less than about 10⁻⁵ M, for example less than about 10⁻⁶ M, 10⁻⁷ M, 10⁻⁸ M, 10⁻⁹ M, or 10⁻¹⁰ M or less. Those skilled in the art can determine the KD based on commonly used biological methods.

[0045] In this application, the term "vector" generally refers to a nucleic acid molecule capable of self-replication within a suitable host, which transfers the inserted nucleic acid molecule to host cells and / or between host cells. The vector may include vectors primarily for inserting DNA or RNA into cells, vectors primarily for replicating DNA or RNA, and vectors primarily for DNA or RNA replication.A vector for transcription and / or translation of expression. The vector also includes vectors having a variety of the functions described above. The vector may be a polynucleotide capable of being transcribed and translated into a polypeptide when introduced into a suitable host cell. Typically, by culturing a suitable host cell containing the vector, the vector can produce the desired expression product.

[0046] In this application, the term "composition" generally refers to a unit dose form and can be prepared by any method well known in the pharmaceutical industry. All methods involve the step of combining an active ingredient with a carrier constituting one or more adjunct components. Typically, a composition is prepared by uniformly and sufficiently combining an active compound with a liquid carrier, a finely pulverized solid carrier, or both.

[0047] In this application, the term "pharmaceutically acceptable" refers to a substance suitable for human and / or mammalian use without excessive adverse side effects (such as toxicity, irritation, and allergic reactions), i.e., a substance with a reasonable benefit / risk ratio.

[0048] In this application, the term "pharmaceuticalally acceptable excipient" may include any solvent, solid excipient, diluent, or other liquid excipient, etc., suitable for a specific target dosage form. The use of any conventional excipients that are incompatible with the compounds of the present invention, such as any adverse biological effects produced or interactions with any other component of a pharmaceutically acceptable composition in a harmful manner, is also within the scope of this invention.

[0049] In this application, the term “administration” means the introduction of a predetermined amount of a substance into a patient in a suitable manner. The antibodies or antigen-binding fragments, recombinant proteins, multispecific antibodies, conjugates, or pharmaceutical compositions of this application may be administered by any common route, as long as it can reach the intended tissue. Various routes of administration are contemplated, including peritoneal, intravenous, intramuscular, subcutaneous, etc., but the invention is not limited to these exemplified routes of administration. Preferably, the compositions of the present invention are administered by intravenous or subcutaneous injection.

[0050] In this application, the term “treatment” means used to refer to obtaining the desired pharmacological and / or physiological effect. The effect may be preventive in terms of complete or partial prevention of the disease or its symptoms, and / or therapeutic in terms of partial or complete cure of the disease and / or adverse effects caused by the disease. As used herein, “treatment” encompasses diseases in mammals, particularly humans, including: (a) preventing the onset of disease or symptoms in individuals who are susceptible but have not yet been diagnosed with the disease; (b) inhibiting disease, such as blocking disease progression; or (c) alleviating disease, such as reducing symptoms associated with the disease. As used herein, “treatment” encompasses any administration of a drug or compound to an individual to treat, cure, alleviate, improve, reduce, or inhibit the individual’s disease, including but not limited to administering a drug containing the compounds described herein to an individual in need.

[0051] In this application, the terms "effective amount" or "effective dose" refer to an amount that is functional or active in humans and / or animals and is acceptable to humans and / or animals.

[0052] In this application, the amino acid sequences involved are shown in Table 1.

[0053] This application provides an antibody targeting B7H7 or its antigen-binding fragment, expression vector, preparation method, recombinant cells, immunoconjugate, composition, pharmaceutical use, drug, preparation kit use, kit, disease treatment method, and disease treatment use, which will be described in detail below.

[0054] Antibody or antigen-binding fragment thereof

[0055] In one aspect of this application, an antibody or antigen-binding fragment thereof is provided, comprising: a heavy chain complementarity-determining region (HCDR) and a light chain complementarity-determining region (LCDR); wherein the aforementioned HCDR comprises an amino acid sequence selected from at least one of SEQ ID NO: 1-3 or having at least 80% homology thereto; and the LCDR comprises an amino acid sequence selected from at least one of SEQ ID NO: 4-6 or having at least 80% homology thereto. In some examples of this application, an antibody or antigen-binding fragment thereof having the aforementioned HCDR and LCDR amino acid sequences is capable of binding human and cynomolgus monkey B7H7 proteins with high affinity and specificity.

[0056] In some examples of this application, the aforementioned HCDR includes: HCDR1, HCDR2, and HCDR3, wherein the aforementioned HCDR1 contains an amino acid sequence as shown in SEQ ID NO:1 or having at least 80% homology with SEQ ID NO:1, the aforementioned HCDR2 contains an amino acid sequence as shown in SEQ ID NO:2 or having at least 80% homology with SEQ ID NO:2, and the aforementioned HCDR3 contains an amino acid sequence selected from those shown in SEQ ID NO:3 or having at least 80% homology with SEQ ID NO:3. Antibodies or antigen-binding fragments based on the aforementioned HCDR sequences have high binding affinity and binding specificity to B7H7.

[0057] In some preferred examples of this application, the aforementioned HCDR includes: HCDR1 with an amino acid sequence as shown in SEQ ID NO:1; HCDR2 with an amino acid sequence as shown in SEQ ID NO:2; and HCDR3 with an amino acid sequence as shown in SEQ ID NO:3. Experimental verification shows that antibodies or their antigen-binding fragments having amino acid sequences as shown in SEQ ID NO:1-3 have high binding affinity and specificity to B7H7.

[0058] In some examples of this application, the aforementioned LCDR includes: LCDR1, LCDR2 and LCDR3, wherein the aforementioned LCDR1 contains as shown in SEQ ID NO:4 or the same as SEQ ID NO:3.NO:4 has an amino acid sequence with at least 80% homology, the aforementioned LCDR2 contains an amino acid sequence as shown in SEQ ID NO:5 or with at least 80% homology to SEQ ID NO:5, and the aforementioned LCDR3 contains an amino acid sequence as shown in SEQ ID NO:6 or with at least 80% homology to SEQ ID NO:6. Antibodies or antigen-binding fragments based on the aforementioned LCDR sequences have high binding affinity and specificity to B7H7.

[0059] In some preferred examples of this application, the aforementioned LCDRs include: LCDR1 with an amino acid sequence as shown in SEQ ID NO:4; LCDR2 with an amino acid sequence as shown in SEQ ID NO:5; and LCDR3 with an amino acid sequence as shown in SEQ ID NO:6. Experimental verification shows that antibodies or antigen-binding fragments having amino acid sequences as shown in SEQ ID NO:4 to 6 have high binding affinity and specificity to B7H7.

[0060] It should be noted that one or more amino acid residues in the aforementioned B7H7-targeting antibody HCDR and / or LCDR can be replaced by other amino acid residues from the same side chain family, and the retained function of the modified antibody can be tested using the functional assay methods described herein. Preferably, the number of conserved modifications does not exceed one or two.

[0061] In some examples of this application, the aforementioned antibody or its antigen-binding fragment further includes a heavy chain framework region.

[0062] In some examples of this application, the aforementioned antibody or its antigen-binding fragment further includes a light chain framework region.

[0063] In some examples of this application, at least a portion of the aforementioned heavy chain framework region and the aforementioned light chain framework region are independently derived from at least one of rabbit-derived antibodies, mouse-derived antibodies, sheep-derived antibodies, goat-derived antibodies, primate-derived antibodies, or mutants thereof.

[0064] In some preferred examples of this application, the heavy chain variable region of the aforementioned antibody or its antigen-binding fragment contains an amino acid sequence selected from or having at least 80% homology with SEQ ID NO:7. In some preferred embodiments of this application, the amino acid sequence of the heavy chain variable region of the aforementioned antibody or its antigen-binding fragment is as shown in SEQ ID NO:7.

[0065] In some preferred embodiments of this application, the light chain variable region of the aforementioned antibody or its antigen-binding fragment contains an amino acid sequence as shown in SEQ ID NO:8 or having at least 80% homology with SEQ ID NO:8. In some more preferred embodiments of this application, the amino acid sequence of the light chain variable region of the aforementioned antibody or its antigen-binding fragment is as shown in SEQ ID NO:8.

[0066] Based on the above-described heavy chain variable region and light chain variable region sequences, the antibody or its antigen-binding fragment binds to B7H7. (Specification 7 / 16, page 11)CN 121005781 A has high affinity and specificity.

[0067] In some examples of this application, the aforementioned antibody or its antigen-binding fragment further includes: a heavy chain constant region.

[0068] In some examples of this application, the aforementioned antibody or its antigen-binding fragment further includes: a light chain constant region.

[0069] In some examples of this application, at least a portion of the aforementioned heavy chain constant region and the aforementioned light chain constant region are independently derived from at least one of rabbit-derived antibodies, mouse-derived antibodies, sheep-derived antibodies, goat-derived antibodies, primate-derived antibodies, or mutants thereof.

[0070] In some preferred examples of this application, at least a portion of the aforementioned heavy chain constant region and the aforementioned light chain constant region are derived from human antibodies.

[0071] In some preferred examples of this application, the aforementioned heavy chain constant region is selected from the human IgG1 constant region.

[0072] In some more preferred examples of this application, the aforementioned human IgG1 constant region has an L234A / L235A mutation.

[0073] It should be noted that L234A represents a mutation of leucine (Leu, L) at position 234 to alanine (Ala, A); similarly, L235A represents a mutation of leucine (Leu, L) at position 235 to alanine (Ala, A).

[0074] In some preferred embodiments of this application, the aforementioned light chain constant region is selected from the human Ig kappa constant region.

[0075] In some embodiments of this application, the heavy chain of the aforementioned antibody or its antigen-binding fragment contains an amino acid sequence selected from or having at least 80% homology with SEQ ID NO:9. In some preferred embodiments of this application, the amino acid sequence of the heavy chain of the aforementioned antibody or its antigen-binding fragment is as shown in SEQ ID NO:9.

[0076] In some embodiments of this application, the light chain of the aforementioned antibody or its antigen-binding fragment contains an amino acid sequence selected from or having at least 80% homology with SEQ ID NO:10. In some preferred embodiments of this application, the light chain amino acid sequence of the aforementioned antibody or its antigen-binding fragment is as shown in SEQ ID NO:10.

[0077] In some embodiments of this application, the aforementioned antibody includes at least one selected from polyclonal antibodies and monoclonal antibodies; or the aforementioned antigen-binding fragment includes at least one selected from F(ab')2 fragment, Fab' fragment, Fab fragment, F(ab)2 fragment, Fv fragment, scFv fragment, scFv-Fc fusion protein, scFv-Fv fusion protein and minimum recognition unit. In some preferred embodiments of this application, the aforementioned antibody is a monoclonal antibody.

[0078] Nucleic Acid Molecule

[0079] In another aspect of this application, this application proposes a nucleic acid molecule that encodes the aforementioned antibody or its antigen-binding fragment. Based on the aforementioned nucleic acid molecule, the aforementioned antibody or its antigen-binding fragment can be prepared in large quantities in vitro.

[0080] In some examples of this application, the aforementioned nucleic acid molecule is DNA.

[0081] It should be noted that, for the nucleic acid molecules mentioned in the specification and claims of this application, those skilled in the art should understand that they actually include any one or both of the complementary double strands. For convenience, although only one strand is given in most cases in this specification and claims, the other complementary strand is actually disclosed. In addition, the nucleic acid sequence in this application includes DNA or RNA forms, and disclosing one means that the other is also disclosed.

[0082] Expression Vector

[0083] In another aspect of this application, this application proposes an expression vector, which carries the aforementioned nucleic acid molecule. Based on the aforementioned expression vector, the aforementioned antibody or its antigen-binding fragment can be prepared in large quantities in vitro.

[0084] It should be noted that, when the aforementioned nucleic acid molecule is linked to the vector, the aforementioned nucleic acid molecule and the control elements on the vector can be directly or indirectly connected, as long as these control elements can control the translation and expression of the aforementioned nucleic acid molecule. Of course, these control elements can come directly from the vector itself or be exogenous, such as promoter sequences, transcription initiation sequences, enhancer sequences, selection elements, and reporter genes. Naturally, the aforementioned nucleic acid molecules and control elements can be operatively linked.

[0085] In some examples of this application, the aforementioned vector refers to a nucleic acid delivery vehicle into which polynucleotides can be inserted. When the vector enables the expression of the protein encoded by the inserted polynucleotide, the vector is called an expression vector. The vector can be introduced into host cells through transformation, transduction, or transfection, allowing the genetic material elements it carries to be expressed in the host cells. Vectors are known to those skilled in the art and include, but are not limited to: plasmids, bacterial microparticles, Cos plasmids, artificial chromosomes, such as yeast artificial chromosomes (YAC), bacterial artificial chromosomes (BAC), or P1-derived artificial chromosomes (PAC); bacterial cells, such as endocytic cells or M13 bacterial cells, and animal viruses, etc. Animal viruses that can be used as vectors include, but are not limited to, retrotranscriptoviruses (including lentiviruses), adenoviruses, adeno-associated viruses, herpesviruses (such as herpes simplex virus), poxviruses, baculoviruses, papillomaviruses, and papillomaviruses (such as SV40). A vector may contain a variety of elements that control expression, including but not limited to, promoter sequences, transcription initiation sequences, enhancer sequences, selection elements, and reporter genes. In addition, the vector may also contain a replication initiation site.

[0086] In this application, the term "operably linked" means linking a foreign gene to a vector such that the control elements within the vector, such as transcription-controlled amino acid sequences and translation-controlled amino acid sequences, can perform their intended functions.The expression vector is used to regulate the transcription and translation of exogenous genes. Commonly used vectors include viral vectors, plasmids, bacteriophages, etc. After the expression vector of some specific embodiments of the present invention is introduced into a suitable recipient cell, the expression of the aforementioned nucleic acid molecules can be effectively realized under the mediation of the regulatory system, thereby realizing the in vitro large-scale acquisition of the protein encoded by the aforementioned nucleic acid molecules.

[0087] In some examples of this application, the aforementioned vector is a eukaryotic vector or a prokaryotic vector.

[0088] In some examples of this application, the aforementioned vector includes at least one selected from plasmid vectors, adenovirus vectors, lentivirus vectors and adeno-associated virus vectors.

[0089] Method for preparing antibody or antigen-binding fragment thereof

[0090] In another aspect of this application, this application proposes a method for preparing the aforementioned antibody or antigen-binding fragment thereof, comprising: introducing the aforementioned expression vector into a cell; culturing the aforementioned cell under conditions suitable for protein expression and secretion in order to obtain the aforementioned antibody or antigen-binding fragment thereof. This method enables the in vitro large-scale preparation of antibody or antigen-binding fragment thereof.

[0091] In some examples of this application, the aforementioned cell is a eukaryotic cell.

[0092] In some specific examples of this application, the aforementioned eukaryotic cells are mammalian cells. When the cell is a mammalian cell, the expression efficiency of the aforementioned antibody or its antigen-binding fragment is relatively high.

[0093] It should be noted that the aforementioned eukaryotic cells do not include animal germ cells, fertilized eggs, or embryonic stem cells.

[0094] Recombinant Cells

[0095] In another aspect of this application, this application proposes a recombinant cell carrying the aforementioned antibody or its antigen-binding fragment, the aforementioned nucleic acid molecule, or the aforementioned expression vector. In some examples of this application, the aforementioned recombinant cells are obtained by transfection or transformation of the aforementioned expression vector, and the aforementioned recombinant cells can efficiently express the aforementioned antibody or antigen-binding fragment under suitable conditions.

[0096] In some examples of this application, the aforementioned recombinant cells are prokaryotic cells, eukaryotic cells, or bacteriophages. It should be noted that the aforementioned eukaryotic cells do not include animal germ cells, fertilized eggs, or embryonic stem cells.

[0097] In some examples of this application, the aforementioned prokaryotic cells are Escherichia coli, Bacillus subtilis, Streptomyces, or Proteus mirabilis.

[0098] In some examples of this application, the aforementioned eukaryotic cells are fungal, insect, plant, or mammalian cells.

[0099] In some examples of this application, the aforementioned fungi are Pichia pastoris, Saccharomyces cerevisiae, Schizosoma fissicola, or Trichoderma.

[0100] In some examples of this application, the aforementioned insect cells are armyworm cells; in some examples of this application, the aforementioned plant cells are tobacco plant cells; in some examples of this application, the aforementioned mammalian cells are BHK cells, CHO cells, etc.Cells, COS cells, myeloma cells, or human embryonic kidney 293 cells; but excluding animal germ cells, fertilized eggs, or embryonic stem cells.

[0101] In some examples of this application, the aforementioned recombinant cells are mammalian cells. When the cell is a mammalian cell, the expression efficiency of the aforementioned antibody or its antigen-binding fragment is higher.

[0102] In some examples of this application, the aforementioned recombinant cells are BHK cells, CHO cells, COS cells, or NSO cells.

[0103] It should be noted that the "suitable conditions" mentioned above in this application specification refer to conditions suitable for the expression of the bispecific antibody of this application. It is readily understood by those skilled in the art that suitable conditions for bispecific antibody expression include, but are not limited to, suitable transformation or transfection methods, suitable transformation or transfection conditions, healthy host cell state, suitable host cell density, suitable cell culture environment, and suitable cell culture time. "Suitable conditions" are not particularly limited, and those skilled in the art can optimize the most suitable conditions for bispecific antibody expression according to the specific environment of the laboratory.

[0104] Immunoconjugate

[0105] In another aspect of this application, an immunoconjugate is provided, comprising: the aforementioned antibody or its antigen-binding fragment, the aforementioned nucleic acid molecule, the aforementioned expression vector, or the aforementioned recombinant cell. The aforementioned immunoconjugate can be used to treat diseases related to B7H7, such as tumors.

[0106] In some examples of this application, the aforementioned immunoconjugate may further comprise a therapeutic agent. The aforementioned therapeutic agent comprises at least one of cytokines, immunomodulators, and small molecule drugs.

[0107] Composition

[0108] In another aspect of this application, a composition is provided, comprising: the aforementioned antibody or its antigen-binding fragment, the aforementioned nucleic acid molecule, the aforementioned expression vector, the aforementioned recombinant cell, or the aforementioned immunoconjugate. The aforementioned composition can be used to treat diseases related to B7H7, such as tumors.

[0109] It should be noted that the aforementioned composition includes combinations that are separate in time and / or space, as long as they can work together to achieve the purpose of the present invention. For example, the components contained in the aforementioned composition can be administered to the subject as a whole or separately. When the components contained in the aforementioned composition are administered separately to a subject, the components may be administered to the subject simultaneously or sequentially.

[0110] Pharmaceutical Use

[0111] In another aspect of this application, this application proposes the use of the aforementioned antibody or its antigen-binding fragment, the aforementioned nucleic acid molecule, the aforementioned expression vector, the aforementioned recombinant cell, the aforementioned immunoconjugate, or the aforementioned composition in the preparation of a medicament for the treatment or prevention of B7H7-mediated diseases. A medicament prepared based on the aforementioned antibody or its antigen-binding fragment can block the binding of B7H7 to its receptor KIR3DL3, promoting the killing of tumor cells by immune cells, thereby effectively treating and / or preventing B7H7-mediated diseases.

[0112] In some examples of this application, the aforementioned B7H7-mediated related diseases include tumors.

[0113] In some examples of this application, the aforementioned tumors include at least one of head and neck cancer, glioma, thyroid cancer, lung cancer, colorectal cancer, gastric cancer, liver cancer, bile duct cancer, breast cancer, ovarian cancer, endometrial cancer, kidney cancer, prostate cancer, bladder cancer, pancreatic cancer, melanoma, multiple myeloma, and acute myeloid leukemia. Specification 10 / 16 pages 14 CN 121005781 A

[0114] Drug

[0115] In another aspect of this application, this application proposes a drug comprising: the aforementioned antibody or its antigen-binding fragment, the aforementioned nucleic acid molecule, the aforementioned expression vector, the aforementioned recombinant cell, the aforementioned immune conjugate, or the aforementioned composition, wherein the aforementioned drug is used for or to prevent B7H7-mediated related diseases. The aforementioned drug can block the binding of B7H7 to its receptor KIR3DL3, promote the killing of tumor cells by immune cells, thereby effectively treating and / or preventing B7H7-mediated diseases.

[0116] In some examples of this application, the aforementioned B7H7-mediated related diseases include tumors.

[0117] In some examples of this application, the aforementioned tumors include at least one of head and neck cancer, glioma, thyroid cancer, lung cancer, colorectal cancer, gastric cancer, liver cancer, bile duct cancer, breast cancer, ovarian cancer, endometrial cancer, kidney cancer, prostate cancer, bladder cancer, pancreatic cancer, melanoma, multiple myeloma, and acute myeloid leukemia.

[0118] In some examples of this application, it further includes pharmaceutically acceptable excipients.

[0119] In some examples of this application, the aforementioned excipients include: one or more pharmaceutically acceptable excipients, diluents, stabilizers, or carriers.

[0120] In some examples of this application, the aforementioned pharmaceutical composition is an injection.

[0121] It should be noted that the aforementioned pharmaceutical composition includes combinations that are separate in time and / or space, as long as they can work together to achieve the purpose of the present invention. For example, the components contained in the aforementioned pharmaceutical composition can be administered to the subject as a whole or separately. When the components contained in the aforementioned pharmaceutical composition are administered to a subject separately, the components may be administered to the subject simultaneously or sequentially.

[0122] The pharmaceutical product of this application contains a safe and effective amount of the active ingredient (bispecific antibody) of this application and pharmaceutically acceptable excipients. Such excipients include (but are not limited to): saline, buffer solution, glucose, water, glycerol, ethanol, and combinations thereof. Generally, pharmaceutical formulations should be matched with the route of administration. The dosage forms of the pharmaceutical product of this application are injections, oral formulations (tablets, capsules, oral liquids), transdermal preparations, and sustained-release preparations. For example, they are prepared using physiological saline or aqueous solutions containing glucose and other excipients by conventional methods. The aforementioned pharmaceutical products are preferably manufactured under aseptic conditions.

[0123] The effective amount of the active ingredient described above in this application may vary depending on the administration method and the severity of the disease to be treated. The preferred effective amount can be determined by those skilled in the art based on various factors (e.g., through clinical trials). The aforementioned factors include, but are not limited to: the pharmacokinetic parameters of the aforementioned active ingredient, such as bioavailability, metabolism, half-life, etc.; the severity of the disease to be treated, the patient's weight, the patient's immune status, the route of administration, etc. For example, due to the urgency of the treatment condition, several separate doses may be given daily, or the dose may be reduced proportionally.

[0124] The pharmaceutically acceptable excipients described above in this application include (but are not limited to): water, saline, liposomes, lipids, proteins, protein-antibody conjugates, peptides, cellulose, nanogels, or combinations thereof. The choice of carrier should be matched with the administration method, which are well known to those skilled in the art.

[0125] Use in the preparation of a kit

[0126] In another aspect of this application, the use of the aforementioned antibody or its antigen-binding fragment in the preparation of a kit for the detection of B7H7 is proposed.

[0127] As mentioned above, the antibody or its antigen-binding fragment of the present application embodiments can specifically bind to B7H7. Therefore, the aforementioned antibody or its antigen-binding fragment can be used to detect B7H7. Furthermore, it can be used to prepare B7H7-related kits for scientific research, such as qualitative or quantitative detection of B7H7 protein molecules in biological samples. More specifically, it can be used in kits involving the specific binding properties of B7H7 and antibodies for detection, such as immunoblotting and immunoprecipitation. These kits may contain any one or more of the following: antagonist, the bispecific antibody of the present invention, or pharmaceutical reference material; purification column; immunoglobulin affinity purification buffer; and cell assay diluent. The bispecific antibody of the present application can be used for different types of diagnostic tests, such as detecting the presence of various diseases, drugs, toxins, or other proteins in vitro or in vivo. For example, it can be used to test for B7H7-mediated diseases by detecting the serum or blood of a subject.

[0128] Kit

[0129] In another aspect of this application, a kit is provided comprising the antibody or antigen-binding fragment thereof described in the first aspect. The aforementioned kit can be used for portable detection of B7H7.

[0130] Disease Treatment Method

[0131] In another aspect of this application, a method for preventing and / or treating B7H7-mediated diseases is provided. According to embodiments of this application, the aforementioned method includes administering to a subject a pharmaceutically acceptable amount of an antibody or antigen-binding fragment thereof, an expression vector, recombinant cells, an immunoconjugate, a composition, or a drug. Based on the aforementioned method, diseases mediated by B7H7 can be effectively treated.Mediated related diseases.

[0132] It should be noted that the terms “subject,” “individual,” and “patient” are used interchangeably herein and refer to a mammal being evaluated for treatment and / or being treated. In one embodiment, the mammal is a human. The terms “subject,” “individual,” and “patient” include, but are not limited to, individuals with tumors, individuals with autoimmune diseases, individuals with pathogen infections, etc. Subjects may be humans, but also include other mammals, particularly mammals that can be used as laboratory models of human diseases, such as mice, rats, etc.

[0133] The effective amount of the antibody or its antigen-binding fragment, nucleic acid molecule, expression vector, immunoconjugate, composition, or drug described above in this application may vary depending on the mode of administration and the severity of the disease to be treated, etc. The preferred effective amount can be determined by those skilled in the art based on various factors (e.g., through clinical trials). The aforementioned factors include, but are not limited to: the pharmacokinetic parameters of the aforementioned active ingredient, such as bioavailability, metabolism, half-life, etc.; the severity of the disease to be treated in the patient, the patient's weight, the patient's immune status, the route of administration, etc. For example, due to the urgent need for treatment, several separate doses may be given daily, or the dose may be reduced proportionally.

[0134] In some examples of this application, the aforementioned B7H7-mediated related diseases include tumors.

[0135] In some examples of this application, the aforementioned tumors include at least one of head and neck cancer, glioma, thyroid cancer, lung cancer, colorectal cancer, gastric cancer, liver cancer, bile duct cancer, breast cancer, ovarian cancer, endometrial cancer, kidney cancer, prostate cancer, bladder cancer, pancreatic cancer, melanoma, multiple myeloma, and acute myeloid leukemia.

[0136] Use for Disease Treatment

[0137] In another aspect of this application, the use of the aforementioned antibody or its antigen-binding fragment, nucleic acid molecule, expression vector, immunoconjugate, composition, or drug in the treatment or prevention of B7H7-mediated diseases is proposed. In some examples of this application, administration of an effective dose of the antibody or its antigen-binding fragment, nucleic acid molecule, expression vector, immunoconjugate, composition, or drug to a subject can effectively treat B7H7-mediated diseases.

[0138] In some examples of this application, the aforementioned B7H7-mediated related diseases include tumors.

[0139] In some examples of this application, the aforementioned tumors include at least one of head and neck cancer, glioma, thyroid cancer, lung cancer, colorectal cancer, gastric cancer, liver cancer, bile duct cancer, breast cancer, ovarian cancer, endometrial cancer, kidney cancer, prostate cancer, bladder cancer, pancreatic cancer, melanoma, multiple myeloma, and acute myeloid leukemia.

[0140] Table 1. B7H7 antibody sequence specification 12 / 16 pages 16 CN 121005781 A

[0141]

[0142] The following will explain the scheme of this application in conjunction with the embodiments. Those skilled in the art will understand that the following embodiments are only used to illustrate this application and should not be regarded as limiting the scope of this application. Where no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in the art or the product instructions shall be followed. Where the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0143] Example 1 Antibody Affinity Maturation

[0144] In order to improve the druggability of the antibody and obtain a high-affinity B7H7 antibody, the applicant performed affinity maturation on the developed humanized B7H7 antibody h17H7B8 (application number: 202311708700.1) (completed by Baiying Bio). The antigen used for affinity maturation is the human B7H7 protein (ACRO) with His tag. The obtained affinity-matured B7H7 antibody h17H7B8-V13 heavy chain variable region is shown as SEQ ID NO:7, and the light chain variable region is shown as SEQ ID NO:8.

[0145] Example 2 Antibody Affinity Detection

[0146] Surface plasmon resonance (SPR) technology was used to determine the affinity of humanized B7H7 antibodies. Instructions 13 / 16 pages 17 CN 121005781 A

[0147] The specific operation is as follows: Turn on the Biacore 1K instrument (Cytiva), place the Protein A chip (Cytiva) into it, then equilibrate it in HBS-EP+ buffer, and then flow the antibody to be tested at a concentration of 0.5 μg / mL through the chip surface at a rate of 30 μL / min to capture the antibody; flow different concentrations of human B7H7 protein (ACRO) through the chip surface at a rate of 30 μL / min, set the binding time to 90 s, and then dissociate for 600 s. Kinetic analysis was performed using a 1:1 binding model. The affinity values ​​of the humanized B7H7 antibody for human B7H7 protein are shown in Table 2, indicating that the humanized B7H7 antibody has significant binding activity to human B7H7 protein.

[0148] Table 2. Affinity values ​​of humanized B7H7 antibody

[0149] Antibody antigen Ka (1 / Ms) Kd (1 / s) KD (M) h17H7B8 Human B7H7 1.93E+05 7.96E-05 4.13E-10 h17H7B8-V13 Human B7H7 3.80E+05 3.49E-05 9.20E-11

[0150] Example 3 Antibody binding activity detection

[0151] Test Example 1 Binding of B7H7 antibody to human and cynomolgus monkey B7H7 protein

[0152] ELISA assay was used to detect the binding of B7H7 antibody to human and cynomolgus monkey B7H7 protein.

[0153] Human and cynomolgus monkey B7H7 protein (ACRO) were diluted to 1 μg / mL with PBS buffer and added to 96-well plates at a volume of 100 μL / well. The plates were incubated overnight at 4°C. The PBS buffer was discarded, and the plates were washed three times with PBST (pH 7.2 PBS containing 0.1% Tween 20). 300 μL / well of 5% BSA was added for blocking, and the plates were incubated at room temperature for 2 h. The blocking buffer was discarded, and 100 μL of the antibody diluted with 0.05% BSA was added. The plates were incubated at room temperature for 1 h. After washing three times with PBST, 100 μL of HRP-labeled anti-human IgG antibody (Southern Biotech) diluted with 0.5% BSA was added. The plates were incubated at room temperature for 1 h. After washing three times with PBST, 80 μL / well of TMB was added, and the plates were incubated at room temperature for 10 min. The reaction was terminated by adding 80 μL / well of stop solution. The absorbance was read at 450 nm using an ELISA reader. The specific experimental results are shown in Figure 1. The affinity maturation antibody (h17H7B8-V13) of this application can bind to human and cynomolgus monkey B7H7 protein, and is stronger than the maternal antibody h17H7B8.

[0154] Test Example 2: Binding of B7H7 antibody to HCC827 cell line

[0155] Flow cytometry was used to detect the ability of B7H7 antibody to bind to the HCC827 cell line.

[0156] The HCC827 cells were diluted to 1×10⁶ cells / mL with PBS and added to a 96-well plate at a volume of 90 μL / well. 10 μL of goat serum (Shanghai Sangon Biotech) was added to each well, and the plate was blocked at 4°C for 30 min. A series of serially diluted test antibodies were added, and the plates were incubated at 4°C for 30 min. After incubation, the plates were washed twice with PBS. Cells were resuspended in 100 μL / well PBS, and 0.1 μL / well of AF647-labeled goat anti-human IgG Fc fragment specific antibody (Jackson ImmunoResearch) was added. The cells were incubated at 4°C in the dark for 30 min. Cells were washed twice with PBS. Cells were then resuspended in 200 μL / well PBS and analyzed by flow cytometry. Figure 2 shows that the affinity maturation antibody (h17H7B8-V13) of this application can bind well to the HCC827 tumor cell line that highly expresses B7H7, and is stronger than the parent antibody h17H7B8.

[0157] Example 4 Antibody Blocking Activity Detection

[0158] Test Example 1 B7H7 Antibody Blocks the Binding of B7H7 Protein to KIR3DL3 Protein

[0159] The ELISA experiment was used to detect the blocking effect of B7H7 antibody on the binding of B7H7 protein to KIR3DL3 protein. The specific experimental operation is as follows:

[0160] Human B7H7 protein (ACRO) was diluted to 5 μg / mL with PBS buffer and added to a 96-well plate at a volume of 100 μL / well.Incubate overnight at 4°C. Discard the PBS buffer in the 96-well plate, wash three times with PBST (pH 7.2 PBS containing 0.1% Tween 20) buffer, add 300 μL / well of 5% BSA, and incubate at room temperature for 2 h for blocking. Discard the blocking solution, dilute the biotin-tagged KIR3DL3 protein (Kaikai Biotechnology) to 2 μg / mL with 0.05% BSA, add 50 μL to each well, and simultaneously add 50 μL of the antibody diluted with 0.05% BSA, and incubate at room temperature for 1 h. Wash three times with PBST, add 100 μL of HRP-labeled Streptavidin secondary antibody diluted with 0.5% BSA (see instructions page 14 / 16, 18 CN 121005781 A), and incubate at room temperature for 1 h. After washing the plate three times with PBST, 80 μL of TMB was added to each well, and the plate was incubated at room temperature for 10 min. The reaction was then terminated by adding 80 μL of stop solution per well. The absorbance was read at 450 nm using a microplate reader. The specific experimental results are shown in Figure 3. The affinity maturation antibody (h17H7B8-V13) of this application can effectively block the binding of B7H7 to its receptor KIR3DL3, and its blocking ability is comparable to that of the parent antibody h17H7B8.

[0161] Test Example 2: B7H7 Antibody Blocks Binding of B7H7 Protein to CHO-K1-KIR3DL3 Cells

[0162] Flow cytometry was used to detect the blocking effect of B7H7 antibody on the binding of B7H7 protein to CHO-K1-KIR3DL3 cells. The specific experimental procedure is as follows:

[0163] CHO-K1-human KIR3DL3 cells were diluted to 2×106 cells / mL with PBS and added to a 96-well plate at a volume of 90 μL / well. Then, 10 μL / well of rat serum was added, and the plate was blocked at 4℃ for 30 min. A series of serially diluted test antibodies and biotin-tagged human B7H7 protein (ACRO) with a final concentration of 2 μg / mL were added, and the plate was incubated at 4℃ for 30 min. After incubation, the cells were washed twice with PBS, resuspended in 100 μL / well PBS, and then 0.1 μL / well of APC-labeled Streptavidin antibody (Biolegend) was added. The cells were incubated at 4°C in the dark for 30 min. The cells were washed twice with PBS, centrifuged, and the supernatant was discarded. The cells were resuspended in 200 μL / well PBS and analyzed by flow cytometry. The specific experimental results are shown in Figure 4. The affinity maturation antibody (h17H7B8-V13) of this application can effectively block the binding of B7H7 to its receptor KIR3DL3, and is stronger than the parent antibody h17H7B8.

[0164] Example 5: Activity detection of high-affinity humanized antibody promoting PBMC killing function

[0165] Flow cytometry was used to detect the activity of the B7H7 antibody in promoting PBMC killing.

[0166] K562-B7H7 cells were collected, the cell pellet was resuspended in 1640 medium, and the cells were counted. The cell density was adjusted to approximately 1.5 × 10⁶ cells / mL. 1 mL of cell suspension was placed in a 1.5 mL EP tube, 1 μL of Cell Trace Violet (Invitrogen) was added, and the mixture was mixed and labeled at 37 °C for 20 min. The labeled cells were washed three times with 1640 medium, and the cell density was adjusted to 2 × 10⁵ cells / mL. PBMCs (Miaoshun Biotechnology) were collected by centrifugation at 300 g, the cell pellet was resuspended in 1640 medium, and the cells were counted. The PBMC concentration was adjusted to 1 × 10⁶ cells / mL. Add 100 μL / well of diluted K562-B7H7 cells and 100 μL / well of PBMCs to a 96-well round-bottom plate, along with serially diluted test antibodies. Centrifuge at 250 g for 4 min at room temperature, then incubate at 37°C in a 5% CO2 incubator for 4–6 h. After incubation, add 1 μL of 7AAD (BD Bioscience) to each well and mix well. Flow cytometry analysis was performed, and the specific experimental results are shown in Figure 5. The affinity maturation antibody (h17H7B8-V13) of this application effectively promoted the killing of K562 cell lines overexpressing B7H7 by PBMCs in a dose-dependent manner, and was stronger than the parent antibody h17H7B8.

[0167] In summary, the monoclonal antibody prepared in this application has high specificity and affinity, and can effectively bind to human and cynomolgus monkey B7H7 protein, block the binding of B7H7 to its receptor KIR3DL3, and promote the killing ability of immune cells (such as PBMCs) against tumor cells.

[0168] The preferred embodiments of this application have been described in detail above, but this application is not limited thereto. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solutions of this application, including the combination of various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed in this application and all fall within the protection scope of this application.

[0169] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc., means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Additionally, without contradiction, those skilled in the art can combine the different embodiments or examples described herein with their features.Page 15 / 16 19 CN 121005781 A Combination.

[0170] Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present application. Instruction Manual 16 / 16 Page 20 CN 121005781 A Figure 1 Figure 2 Figure 3 Instruction Drawing 1 / 2 Page 21 CN 121005781 A Figure 4 Figure 5 Instruction Drawing 2 / 2 Page 22 CN 121005781 A Abstract Abdominal ultrasound examination method, system and device Title of Invention: High-Affinity B7H7 Antibody or Antigen-Binding Fragment Thereof and Use Thereof Abstract: Provided is a high-affinity B7H7 antibody or antigen-binding fragment thereof and use thereof, relating to the field of antibodies. The antibody or antigen-binding fragment thereof includes heavy chain complementarity determining regions (HCDRs) and light chain complementarity determining regions (LCDRs). LCDRs include at least one amino acid sequence selected from SEQ ID NOs: 4-6 or an amino acid sequence having atleast 80% homology thereto. The antibody or antigen-binding fragment thereof has high specificity and high affinity, is capable of binding to human B7H7 and cynomolgus monkey B7H7, and specifically blocks the binding of B7H7 to its receptor KIR3DL3, thereby promoting immune cell-mediated killing of tumor cells and effectively treating and / or preventing B7H7-mediated related diseases, such as tumors.

Claims

1. An antibody or its antigen-binding fragment, characterized in that, include: Heavy chain complementarity-determining region (HCDR) and light chain complementarity-determining region (LCDR); in, The HCDR contains an amino acid sequence selected from at least one of SEQ ID NO:1-3 or having at least 80% homology with it; The LCDR contains an amino acid sequence selected from at least one of SEQ ID NO:4-6 or having at least 80% homology with it.

2. The antibody or its antigen-binding fragment according to claim 1, characterized in that, The HCDRs include: HCDR1, HCDR2, and HCDR3, wherein: The HCDR1 contains an amino acid sequence as shown in SEQ ID NO:1 or having at least 80% homology with SEQ ID NO:

1. The HCDR2 comprises an amino acid sequence as shown in SEQ ID NO:2 or having at least 80% homology with SEQ ID NO:2, and The HCDR3 comprises an amino acid sequence selected from that shown in SEQ ID NO:3 or having at least 80% homology with SEQ ID NO:3; Preferably, the HCDR comprises: HCDR1 with the amino acid sequence shown in SEQ ID NO:1; Preferably, the HCDR comprises: HCDR2 with the amino acid sequence shown in SEQ ID NO:2; Preferably, the HCDR comprises HCDR3, which has the amino acid sequence shown in SEQ ID NO:

3.

3. The antibody or its antigen-binding fragment according to claim 1, characterized in that, The LCDR includes: LCDR1, LCDR2, and LCDR3, wherein: The LCDR1 contains an amino acid sequence as shown in SEQ ID NO:4 or having at least 80% homology with SEQ ID NO:

4. The LCDR2 comprises an amino acid sequence as shown in SEQ ID NO:5 or having at least 80% homology with SEQ ID NO:5, and The LCDR3 comprises an amino acid sequence as shown in SEQ ID NO:6 or having at least 80% homology with SEQ ID NO:6; Preferably, the LCDR comprises: LCDR1 with an amino acid sequence as shown in SEQ ID NO:4; Preferably, the LCDR comprises: LCDR2 with an amino acid sequence as shown in SEQ ID NO:5; Preferably, the LCDR comprises: LCDR3 with an amino acid sequence as shown in SEQ ID NO:

6.

4. The antibody or its antigen-binding fragment according to claim 2 or 3, characterized in that, The antibody or its antigen-binding fragment further includes: a heavy chain framework region; Optionally, the antibody or its antigen-binding fragment further includes a light chain framework region; Optionally, at least a portion of the heavy chain framework region and the light chain framework region are independently derived from at least one of rabbit-derived antibodies, mouse-derived antibodies, sheep-derived antibodies, goat-derived antibodies, primate-derived antibodies, or mutants thereof; Preferably, the heavy chain variable region of the antibody or its antigen-binding fragment comprises an amino acid sequence selected from or having at least 80% homology with SEQ ID NO:7; preferably, the amino acid sequence of the heavy chain variable region of the antibody or its antigen-binding fragment is as shown in SEQ ID NO:

7. Preferably, the light chain variable region of the antibody or its antigen-binding fragment comprises an amino acid sequence as shown in SEQ ID NO:8 or having at least 80% homology with SEQ ID NO:8; preferably, the amino acid sequence of the light chain variable region of the antibody or its antigen-binding fragment is as shown in SEQ ID NO:

8.

5. The antibody or its antigen-binding fragment according to claim 4, characterized in that, The antibody or its antigen-binding fragment further includes: a heavy chain constant region; Optionally, the antibody or its antigen-binding fragment further includes a light chain constant region; Optionally, at least a portion of the heavy chain constant region and the light chain constant region are independently derived from at least one of rabbit-derived antibodies, mouse-derived antibodies, sheep-derived antibodies, goat-derived antibodies, primate-derived antibodies, or mutants thereof; preferably, at least a portion of the heavy chain constant region and the light chain constant region are derived from human-derived antibodies. Preferably, the heavy chain constant region is selected from the human IgG1 constant region; More preferably, the human IgG1 constant region has an L234A / L235A mutation; Preferably, the light chain constant region is selected from the human Ig kappa constant region; Preferably, the heavy chain of the antibody or its antigen-binding fragment comprises an amino acid sequence selected from or having at least 80% homology with SEQ ID NO:9; preferably, the amino acid sequence of the heavy chain of the antibody or its antigen-binding fragment is as shown in SEQ ID NO:9; Preferably, the light chain of the antibody or its antigen-binding fragment comprises an amino acid sequence selected from or having at least 80% homology with SEQ ID NO:10; preferably, the amino acid sequence of the light chain of the antibody or its antigen-binding fragment is as shown in SEQ ID NO:

10.

6. The antibody or its antigen-binding fragment according to claim 1, characterized in that, The antibody includes at least one selected from polyclonal antibodies and monoclonal antibodies; or The antigen-binding fragment includes at least one selected from the following: F(ab')2 fragment, Fab' fragment, Fab fragment, F(ab)2 fragment, Fv fragment, scFv fragment, scFv-Fc fusion protein, scFv-Fv fusion protein, and minimum recognition unit; Preferably, the antibody is a monoclonal antibody.

7. A nucleic acid molecule, characterized in that, The nucleic acid molecule encodes the antibody or its antigen-binding fragment as described in any one of claims 1 to 6; Optionally, the nucleic acid molecule is DNA.

8. An expression carrier, characterized in that, Carrying the nucleic acid molecule as described in claim 7.

9. A method for preparing the antibody or antigen-binding fragment thereof according to any one of claims 1 to 6, characterized in that, include: The expression vector according to claim 8 is introduced into cells; The cells are cultured under conditions suitable for protein expression and secretion in order to obtain the antibody or its antigen-binding fragment; Optionally, the cells are eukaryotic cells.

10. A recombinant cell, characterized in that, The recombinant cells carry the nucleic acid molecule of claim 7 or the expression vector of claim 8.

11. An immunoconjugate, characterized in that, include: The antibody or antigen-binding fragment thereof according to any one of claims 1 to 6, the nucleic acid molecule according to claim 7, the expression vector according to claim 8, or the recombinant cell according to claim 10; Optionally, the immune conjugate further comprises a therapeutic agent.

12. A composition, characterized in that, include: The antibody or antigen-binding fragment thereof as described in any one of claims 1 to 6, the nucleic acid molecule carrying the nucleic acid molecule as described in claim 7, the expression vector as described in claim 8, the recombinant cell as described in claim 10, or the immunoconjugate as described in claim 11.

13. Use of the antibody or antigen-binding fragment thereof according to any one of claims 1 to 6, carrying the nucleic acid molecule according to claim 7, the expression vector according to claim 8, the recombinant cell according to claim 10, the immunoconjugate according to claim 11, or the composition according to claim 12 in the preparation of a medicament for the treatment or prevention of B7H7-mediated diseases.

14. The use according to claim 13, characterized in that, The B7H7-mediated diseases include tumors; Optionally, the tumor includes at least one of head and neck cancer, glioma, thyroid cancer, lung cancer, colorectal cancer, gastric cancer, liver cancer, bile duct cancer, breast cancer, ovarian cancer, endometrial cancer, kidney cancer, prostate cancer, bladder cancer, pancreatic cancer, melanoma, multiple myeloma, and acute myeloid leukemia.

15. A drug, characterized in that, include: The drug is an antibody or antigen-binding fragment thereof according to any one of claims 1 to 6, a nucleic acid molecule carrying the nucleic acid molecule according to claim 7, an expression vector according to claim 8, a recombinant cell according to claim 10, an immunoconjugate according to claim 11, or a composition according to claim 12, and is used for or to prevent B7H7-mediated diseases.

16. The medicament according to claim 15, characterized in that, The B7H7-mediated diseases include tumors; Optionally, the tumor includes at least one of head and neck cancer, glioma, thyroid cancer, lung cancer, colorectal cancer, gastric cancer, liver cancer, bile duct cancer, breast cancer, ovarian cancer, endometrial cancer, kidney cancer, prostate cancer, bladder cancer, pancreatic cancer, melanoma, multiple myeloma, and acute myeloid leukemia. Optionally, it may further include pharmaceutically acceptable excipients; Optionally, the excipients include: One or more pharmaceutically acceptable excipients, diluents, stabilizers, or carriers; Optionally, the drug is an injectable form.

17. Use of the antibody or antigen-binding fragment thereof according to any one of claims 1 to 6 in the preparation of a kit for detecting B7H7.

18. A reagent kit, characterized in that, The kit contains: The antibody or antigen-binding fragment thereof as described in any one of claims 1 to 6.

19. The reagent kit according to claim 18, characterized in that, The kit is used to detect B7H7.

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