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WO2021058000A1 - 抗人Claudin18.2抗体及其应用 - Google Patents

抗人Claudin18.2抗体及其应用 Download PDF

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WO2021058000A1
WO2021058000A1 PCT/CN2020/118424 CN2020118424W WO2021058000A1 WO 2021058000 A1 WO2021058000 A1 WO 2021058000A1 CN 2020118424 W CN2020118424 W CN 2020118424W WO 2021058000 A1 WO2021058000 A1 WO 2021058000A1
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seq
amino acid
acid sequence
antibody
identity
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PCT/CN2020/118424
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English (en)
French (fr)
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林鉴
邓小芳
高攀
徐晓红
王骊淳
任红媛
毕建军
王晋
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迈威(上海)生物科技股份有限公司
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Priority to AU2020352382A priority Critical patent/AU2020352382A1/en
Priority to CA3156788A priority patent/CA3156788A1/en
Priority to EP20869539.5A priority patent/EP4063386A4/en
Priority to US17/755,427 priority patent/US20230250168A1/en
Priority to JP2022540748A priority patent/JP2023503180A/ja
Priority to KR1020227014700A priority patent/KR20220110177A/ko
Publication of WO2021058000A1 publication Critical patent/WO2021058000A1/zh

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    • A—HUMAN NECESSITIES
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    • C07K16/18—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans
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    • G01—MEASURING; TESTING
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    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
    • G01N33/574—Immunoassay; Biospecific binding assay; Materials therefor for cancer
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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    • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
    • G01N33/574—Immunoassay; Biospecific binding assay; Materials therefor for cancer
    • G01N33/57407—Specifically defined cancers
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K39/00—Medicinal preparations containing antigens or antibodies
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    • C07K2317/20—Immunoglobulins specific features characterized by taxonomic origin
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    • C07K2317/00—Immunoglobulins specific features
    • C07K2317/30—Immunoglobulins specific features characterized by aspects of specificity or valency
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    • C07—ORGANIC CHEMISTRY
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    • C07K2317/00—Immunoglobulins specific features
    • C07K2317/50—Immunoglobulins specific features characterized by immunoglobulin fragments
    • C07K2317/56—Immunoglobulins specific features characterized by immunoglobulin fragments variable (Fv) region, i.e. VH and/or VL
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    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K2317/00—Immunoglobulins specific features
    • C07K2317/50—Immunoglobulins specific features characterized by immunoglobulin fragments
    • C07K2317/56—Immunoglobulins specific features characterized by immunoglobulin fragments variable (Fv) region, i.e. VH and/or VL
    • C07K2317/565—Complementarity determining region [CDR]
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    • C07K2317/60—Immunoglobulins specific features characterized by non-natural combinations of immunoglobulin fragments
    • C07K2317/62—Immunoglobulins specific features characterized by non-natural combinations of immunoglobulin fragments comprising only variable region components
    • C07K2317/622—Single chain antibody (scFv)
    • C—CHEMISTRY; METALLURGY
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    • C07K2317/00—Immunoglobulins specific features
    • C07K2317/70—Immunoglobulins specific features characterized by effect upon binding to a cell or to an antigen
    • C07K2317/73—Inducing cell death, e.g. apoptosis, necrosis or inhibition of cell proliferation
    • C07K2317/732—Antibody-dependent cellular cytotoxicity [ADCC]
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K2317/00—Immunoglobulins specific features
    • C07K2317/70—Immunoglobulins specific features characterized by effect upon binding to a cell or to an antigen
    • C07K2317/73—Inducing cell death, e.g. apoptosis, necrosis or inhibition of cell proliferation
    • C07K2317/734—Complement-dependent cytotoxicity [CDC]
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K2317/00—Immunoglobulins specific features
    • C07K2317/90—Immunoglobulins specific features characterized by (pharmaco)kinetic aspects or by stability of the immunoglobulin
    • C07K2317/92—Affinity (KD), association rate (Ka), dissociation rate (Kd) or EC50 value
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K2319/00—Fusion polypeptide
    • C07K2319/01—Fusion polypeptide containing a localisation/targetting motif
    • C07K2319/03—Fusion polypeptide containing a localisation/targetting motif containing a transmembrane segment
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    • C12N2740/00—Reverse transcribing RNA viruses
    • C12N2740/00011—Details
    • C12N2740/10011—Retroviridae
    • C12N2740/16011—Human Immunodeficiency Virus, HIV
    • C12N2740/16041—Use of virus, viral particle or viral elements as a vector
    • C12N2740/16043—Use of virus, viral particle or viral elements as a vector viral genome or elements thereof as genetic vector

Definitions

  • the present invention belongs to the field of biomedicine, and relates to a new anti-human Claudin 18.2 antibody or functional fragment thereof.
  • the present invention also relates to the application of the antibody or its functional fragment.
  • the human tight junction protein Claudin18 belongs to the tight junction protein family. This type of protein biologically plays a role in the construction of cell tight junctions, the maintenance of cell barrier function and the participation of cell-to-cell molecular transmission.
  • the molecular weight of Claudin18 protein is about 26KD, and Claudin protein can be transformed into Claudin subtypes with different characteristics through alternative splicing: CLDN18.1 and CLDN18.2.
  • CLDN18.1 and CLDN18.2 are composed of 261 amino acids, and both have four transmembrane domains. The NH2 end and the COOH end are located in the cell and have two extracellular loops (Extracellular Loops: ECL1, ECL2). There are only 8 amino acid differences between CLDN18.1 and CLDN18.2 in extracellular domain 1.
  • CLDN18.2 is expressed in the primary lesions and metastases of a variety of human epithelial tumor types, and is continuously expressed in diffuse cancer cells. In esophageal cancer, pancreatic cancer, lung cancer and gastric cancer cells, the expression level of CLDN18.2 is significantly higher. Sahin et al. researched that CLDN 18.2 is an important gastric cancer biomarker, which is present in 70% of gastric cancer patients, among which 90% to 95% are diagnosed as adenocarcinoma, and the other 5-10% include lymphoma, gastrointestinal tract Stromal tumors (GIST) and carcinoid tumors.
  • GIST gastrointestinal tract Stromal tumors
  • IMAB362 The German biotechnology company Ganymed has developed a monoclonal antibody IMAB362 against CLDN18.2, which is currently in phase III clinical trials for the treatment of patients with advanced gastroesophageal cancer.
  • IMAB362 antibody is directed against metastatic esophageal cancer and metastatic gastric cancer indications. It is currently in clinical phase 3 in the United States and the European Union and is expected to apply for listing in 2021.
  • IMAB362 is a chimeric antibody with more murine amino acids, which has a relatively high probability of causing rejection in the human body. Therefore, there is still a need for antibodies, especially humanized antibodies, with higher specificity, affinity and biological activity for human CLDN 18.2 in the art.
  • the two subtypes of Claudin18, CLDN18.1 and CLDN18.2 are highly similar in structure but different in function.
  • CLDN18.1 and CLDN18.2 have a high degree of homology and ECL1 has a high-level structure. The screening is aimed at the high level of CLDN18.2. It is difficult to quality antibodies, and there is a high degree of uncertainty in antibody specificity.
  • the technical problem to be solved by the present invention is to improve the screening efficiency of Claudin 18.2 specific antibodies through the optimization of the monoclonal antibody preparation method, and to obtain high affinity that specifically binds to human CLDN 18.2 through hybridoma screening and humanization technology
  • the present invention uses mouse-derived cells to express human CLDN 18.2.
  • the murine-derived cells used as the host are not immunogenic to mice or have extremely low immunogenicity, thus avoiding the shielding effect of the host cells on the target immunogen CLDN 18.2, and avoiding the introduction of heterologous immunogens.
  • expressing human CLDN18.2 in mouse-derived cells can achieve membrane surface expression, so that the monoclonal antibodies obtained by screening can specifically bind to the extracellular of CLDN18.2 Area to ensure the biological activity of CLDN18.2 specific antibodies.
  • the present invention adopts a combination of forward and reverse screening strategies.
  • Recombinant cells are screened in reverse, and reverse screening can exclude monoclonal antibodies that specifically bind to the common extracellular domain structure of CLDN18.2 and CLDN18.1.
  • the immunogens, forward screening antigens, and reverse screening antigens used in the present invention all use the same mouse-derived cell platform, which not only simplifies the method and avoids the introduction of heterologous antigens, but also eliminates the mouse-derived antigen through the reverse screening step
  • the antibody produced by the effect of the source cell on the allogeneic antigen of the individual mouse further improves the production efficiency of the monoclonal antibody that specifically binds to the extracellular region 2 of CLDN 18.2.
  • Another object of the present invention is to provide an antibody or fragment thereof that specifically binds to human CLDN 18.2, and to provide its use.
  • the antibody fragments of the present invention cover various functional fragments of the antibody, for example, the antigen-binding portion thereof, such as Fab, F(ab') 2 or scFv fragments.
  • the present invention provides a method for preparing an anti-human Claudin 18.2 antibody, including:
  • step (1) Use the animals immunized in step (1) to prepare cell clones capable of producing antibodies;
  • the cells expressing human Claudin 18.2 protein in the step (1) are derived from the same species as the immunized animal, and preferably the cells expressing human Claudin 18.2 protein are The mouse cell and the immunized animal is a mouse.
  • the step (2) is selected from the following technologies to prepare antibody-producing cell clones: hybridoma technology and single cell amplification technology.
  • the forward screening antigen in step (3) is the same as the immunogen in step (1); the reverse screening antigen in step (4) is the same as that in step (1).
  • the only difference between the immunogens in) is that the expressed protein is human Claudin 18.1.
  • the steps (3) and (4) adopt a method selected from the group consisting of enzyme-linked immunoassay (ELISA) and fluorescence resonance energy transfer (FRET).
  • ELISA enzyme-linked immunoassay
  • FRET fluorescence resonance energy transfer
  • the present invention also provides an anti-human Claudin 18.2 antibody obtained according to the method for preparing the anti-human Claudin 18.2 antibody of the invention.
  • the anti-human Claudin 18.2 antibody of the present invention specifically binds to the N-terminus of human Claudin 18.2, and preferably specifically binds to the extracellular region of the human Claudin 18.2 N-terminus, including the first extracellular loop (Extracellular Loop). 1, ECL1).
  • the anti-human Claudin 18.2 antibody of the present invention has nM-level specific binding to human CLDN 18.2; and, its binding to human CLDN 18.1 is equivalent to an isotype-negative antibody (or unrelated antibody) There is no significant difference in comparison.
  • the present invention provides an antibody or fragment thereof, the antibody or fragment thereof comprising a heavy chain variable region (VH) and a light chain variable region (VL), wherein the heavy chain variable region (VH) And the light chain variable region (VL) comprises a combination of CDRs selected from the following (VH-CDR1, VH-CDR2, VH-CDR3; VL-CDR1, VL-CDR2, VL-CDR3):
  • VH-CDR1 as shown in SEQ ID NO: 31, VH-CDR2 as shown in SEQ ID NO: 32, VH-CDR3 as shown in SEQ ID NO: 33; as shown in SEQ ID NO: 34 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 35, VL-CDR3 as shown in SEQ ID NO: 36;
  • VH-CDR1 as shown in SEQ ID NO: 37, VH-CDR2 as shown in SEQ ID NO: 38, VH-CDR3 as shown in SEQ ID NO: 39; as shown in SEQ ID NO: 40 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41, VL-CDR3 as shown in SEQ ID NO: 42;
  • VH-CDR1 as shown in SEQ ID NO: 43, VH-CDR2 as shown in SEQ ID NO: 44, VH-CDR3 as shown in SEQ ID NO: 45; as shown in SEQ ID NO: 46 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41, VL-CDR3 as shown in SEQ ID NO: 47;
  • VH-CDR1 as shown in SEQ ID NO: 48, VH-CDR2 as shown in SEQ ID NO: 49, VH-CDR3 as shown in SEQ ID NO: 50; as shown in SEQ ID NO: 40 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41, VL-CDR3 as shown in SEQ ID NO: 51;
  • VH-CDR1 as shown in SEQ ID NO: 52, VH-CDR2 as shown in SEQ ID NO: 53 and VH-CDR3 as shown in SEQ ID NO: 54; as shown in SEQ ID NO: 55 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41, VL-CDR3 as shown in SEQ ID NO: 56;
  • VH-CDR1 as shown in SEQ ID NO: 57, VH-CDR2 as shown in SEQ ID NO: 58 and VH-CDR3 as shown in SEQ ID NO: 33; as shown in SEQ ID NO: 34 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 59, VL-CDR3 as shown in SEQ ID NO: 60;
  • VH-CDR1 as shown in SEQ ID NO: 61
  • VH-CDR2 as shown in SEQ ID NO: 62
  • VH-CDR3 as shown in SEQ ID NO: 63
  • SEQ ID NO: 46 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41
  • VL-CDR3 as shown in SEQ ID NO: 64;
  • VH-CDR1 as shown in SEQ ID NO: 65
  • VH-CDR2 as shown in SEQ ID NO: 66
  • VH-CDR3 as shown in SEQ ID NO: 67
  • VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41
  • VL-CDR3 as shown in SEQ ID NO: 69;
  • VH-CDR1 as shown in SEQ ID NO: 65
  • VH-CDR2 as shown in SEQ ID NO: 70
  • VH-CDR3 as shown in SEQ ID NO: 71
  • SEQ ID NO: 72 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41
  • VL-CDR3 as shown in SEQ ID NO: 73;
  • VH-CDR1 as shown in SEQ ID NO: 74, VH-CDR2 as shown in SEQ ID NO: 75, VH-CDR3 as shown in SEQ ID NO: 76; as shown in SEQ ID NO: 77 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41, VL-CDR3 as shown in SEQ ID NO: 78;
  • VH-CDR1 as shown in SEQ ID NO: 79, VH-CDR2 as shown in SEQ ID NO: 80, VH-CDR3 as shown in SEQ ID NO: 81; as shown in SEQ ID NO: 82 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41, VL-CDR3 as shown in SEQ ID NO: 83;
  • VH-CDR1 as shown in SEQ ID NO: 37, VH-CDR2 as shown in SEQ ID NO: 38, VH-CDR3 as shown in SEQ ID NO: 39; as shown in SEQ ID NO: 85 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41, VL-CDR3 as shown in SEQ ID NO: 42;
  • VH-CDR1 as shown in SEQ ID NO: 37, VH-CDR2 as shown in SEQ ID NO: 38, VH-CDR3 as shown in SEQ ID NO: 39; as shown in SEQ ID NO: 85 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41, VL-CDR3 as shown in SEQ ID NO: 86;
  • VH-CDR1 as shown in SEQ ID NO: 37, VH-CDR2 as shown in SEQ ID NO: 38, VH-CDR3 as shown in SEQ ID NO: 39; as shown in SEQ ID NO: 85 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41, VL-CDR3 as shown in SEQ ID NO: 87;
  • VH-CDR1 as shown in SEQ ID NO: 74, VH-CDR2 as shown in SEQ ID NO: 75, VH-CDR3 as shown in SEQ ID NO: 76; as shown in SEQ ID NO: 89 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41, VL-CDR3 as shown in SEQ ID NO: 90; and
  • VH-CDR1 as shown in SEQ ID NO: 79, VH-CDR2 as shown in SEQ ID NO: 91, VH-CDR3 as shown in SEQ ID NO: 81; as shown in SEQ ID NO: 92 VL-CDR1, VL-CDR2 as shown in SEQ ID NO: 41, VL-CDR3 as shown in SEQ ID NO: 93.
  • the heavy chain variable region comprises:
  • SEQ ID NO: 1 SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID
  • the light chain variable region includes:
  • SEQ ID NO: 2 SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16, SEQ ID NO: 18, SEQ ID NO: 20, SEQ ID NO: 22, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 28, SEQ ID NO: 30
  • the amino acid sequence shown or an amino acid sequence having at least 75% identity with the amino acid sequence shown.
  • the heavy chain variable region and light chain variable region contained in the antibody or fragment thereof are selected from the following combinations:
  • amino acid sequence shown in SEQ ID NO:1 or an amino acid sequence having at least 75% identity with the amino acid sequence shown in SEQ ID NO:1; and, the amino acid sequence shown in SEQ ID NO:2 Or an amino acid sequence having at least 75% identity with the amino acid sequence shown in SEQ ID NO: 2;
  • amino acid sequence shown in SEQ ID NO: 5 or an amino acid sequence having at least 75% identity with the amino acid sequence shown in SEQ ID NO: 5; and, the amino acid sequence shown in SEQ ID NO: 6 Or an amino acid sequence having at least 75% identity with the amino acid sequence shown in SEQ ID NO: 6;
  • amino acid sequence shown in SEQ ID NO: 13 or the amino acid sequence having at least 75% identity with the amino acid sequence shown in SEQ ID NO: 13; and, the amino acid sequence shown in SEQ ID NO: 14 Or an amino acid sequence having at least 75% identity with the amino acid sequence shown in SEQ ID NO: 14;
  • amino acid sequence shown in SEQ ID NO: 15 or an amino acid sequence having at least 75% identity with the amino acid sequence shown in SEQ ID NO: 15; and, the amino acid sequence shown in SEQ ID NO: 16 Or an amino acid sequence having at least 75% identity with the amino acid sequence shown in SEQ ID NO: 16;
  • amino acid sequence shown in SEQ ID NO: 23 or an amino acid sequence having at least 75% identity with the amino acid sequence shown in SEQ ID NO: 23; and, the amino acid sequence shown in SEQ ID NO: 24 Or an amino acid sequence having at least 75% identity with the amino acid sequence shown in SEQ ID NO: 24;
  • amino acid sequence shown in SEQ ID NO: 23 or an amino acid sequence having at least 75% identity with the amino acid sequence shown in SEQ ID NO: 23; and, the amino acid sequence shown in SEQ ID NO: 26 Or an amino acid sequence having at least 75% identity with the amino acid sequence shown in SEQ ID NO: 26;
  • the at least 75% identity is, for example, at least 80%, preferably at least 85%, more preferably at least 90%, further preferably at least 91%, 92%, 93%, 94%, 95%, 96% , 97%, 98%, or even 99% identity, any percentage of identity ⁇ 75%.
  • the antibodies or fragments thereof provided by the present invention can be monoclonal antibodies, single-chain antibodies, bifunctional antibodies, single-domain antibodies, nanobodies, fully or partially humanized antibodies or chimeric antibodies, etc., or the antibody Or its fragments are half antibodies or antigen binding fragments of half antibodies, such as scFv, BsFv, dsFv, (dsFv) 2 , Fab, Fab', F(ab') 2 or Fv; regarding the fragments of the antibody provided by the present invention, it is preferred Specifically, the fragment is any fragment of the antibody that can specifically bind to human Claudin 18.2.
  • the antibody or fragment thereof further comprises a human or murine constant region, preferably a human or murine light chain constant region (CL) and/or a heavy chain constant region (CH);
  • a human or murine constant region preferably a human or murine light chain constant region (CL) and/or a heavy chain constant region (CH);
  • the antibody or fragment thereof comprises a heavy chain constant region selected from IgG, IgA, IgM, IgD or IgE and/or a kappa or lambda light chain constant region.
  • the antibody is a monoclonal antibody, preferably a murine, chimeric or humanized monoclonal antibody; more preferably, the heavy chain constant region of the monoclonal antibody is of IgG1 or IgG4 subtype, and the light chain The constant region is ⁇ type;
  • the heavy chain constant region of the monoclonal antibody comprises an amino acid sequence as shown in SEQ ID NO: 124 or an amino acid sequence having at least 75% identity with the amino acid sequence;
  • the light chain constant region of the monoclonal antibody comprises an amino acid sequence as shown in SEQ ID NO: 125 or an amino acid sequence having at least 75% identity with the amino acid sequence.
  • the present invention provides a nucleic acid molecule that encodes the antibody or fragment thereof of the present invention, or encodes the heavy chain CDR, light chain CDR, light chain variable region, and heavy chain contained in the antibody or fragment thereof. Variable region, heavy chain or light chain.
  • the nucleic acid molecule encodes the heavy chain variable region or the light chain variable region in the antibody or fragment thereof of the present invention.
  • the nucleic acid molecule includes SEQ ID NOs: 96- The nucleotide sequence shown in any one of 125.
  • the nucleic acid molecule of the present invention can be cloned into a vector, and then transformed or transfected into a host cell. Therefore, in yet another aspect, the present invention provides a vector comprising the nucleic acid molecule of the present invention.
  • the vector can be a eukaryotic expression vector, a prokaryotic expression vector, an artificial chromosome, a phage vector, and the like.
  • the vector or nucleic acid molecule of the present invention can be used to transform or transfect a host cell or enter the host cell in any manner for the purpose of preservation or expression of antibodies. Therefore, in yet another aspect, the present invention provides a host cell that contains the nucleic acid molecule and/or vector of the present invention, or the host cell is transformed or transfected by the nucleic acid molecule and/or vector of the present invention.
  • the host cell can be any prokaryotic or eukaryotic cell, such as a bacterial or insect, fungal, plant or animal cell.
  • the antibodies provided by the present invention can be obtained by any method known in the art.
  • the heavy chain variable region and/or light chain variable region of the antibody can be obtained first from the nucleic acid molecule provided by the present invention, or the heavy chain and/or light chain of the antibody can be obtained, and then combined with any of the antibody Select other domains to assemble into an antibody; or, in the host cell provided by the present invention to allow expression of the heavy chain variable region and/or light chain variable region of the antibody or the heavy chain and/or light chain of the antibody to assemble
  • the host cell is cultured.
  • the method further includes the step of recovering the produced antibody.
  • the present invention provides a conjugate or fusion protein, which comprises the antibody or fragment thereof provided by the present invention.
  • the conjugate or fusion protein may be a bispecific antibody comprising the antibody or fragment thereof of the present invention.
  • the antibodies or fragments thereof, nucleic acid molecules, vectors, host cells and/or conjugates or fusion proteins provided by the present invention can be included in pharmaceutical compositions, more particularly in pharmaceutical preparations, so as to be used according to actual needs.
  • the present invention also provides a pharmaceutical composition comprising the antibody or fragments thereof, nucleic acid molecules, vectors, host cells and/or conjugates or fusion proteins of the present invention, And optional pharmaceutically acceptable excipients.
  • the present invention also provides a kit, which includes the antibody molecule or fragment thereof, nucleic acid molecule, vector, host cell, pharmaceutical composition and/or conjugate or fusion protein of the present invention.
  • the present invention provides the use of the above-mentioned antibody or fragments, nucleic acid molecules, vectors, host cells, pharmaceutical compositions and/or conjugates or fusion proteins in the preparation of drugs for the prevention and/or treatment of cancer.
  • the cancer is selected from pancreatic cancer, gastric cancer, colon cancer, esophageal cancer, liver cancer, ovarian cancer, lung cancer, gallbladder cancer, and head and neck cancer.
  • the present invention also provides the use of the antibody or fragments thereof, nucleic acid molecules, vectors, host cells, pharmaceutical compositions and/or conjugates or fusion proteins in the preparation of reagents for diagnosing cancer.
  • the cancer is selected from pancreatic cancer, gastric cancer, colon cancer, esophageal cancer, liver cancer, ovarian cancer, lung cancer, gallbladder cancer, and head and neck cancer.
  • the present invention also provides a method for preventing and/or treating cancer, the method comprising administering the antibody or fragment thereof, nucleic acid molecule, vector, host cell, or drug combination of the present invention to a subject in need thereof And/or conjugate or fusion protein, and optionally other drugs or means.
  • the optional other drugs or means refer to other drugs or means that can be administered in combination with the antibody or fragments thereof, nucleic acid molecules, vectors, host cells, pharmaceutical compositions and/or conjugates or fusion proteins of the present invention, such as small molecules Chemical drugs, targeted drugs, antibodies and other recombinant protein drugs, vaccines, ADCs, oncolytic viruses, gene and nucleic acid therapy drugs, and radiotherapy.
  • the combined administration of the two can be carried out in any form, for example, simultaneously, continuously or at a certain time interval.
  • the cancer is selected from pancreatic cancer, gastric cancer, colon cancer, esophageal cancer, liver cancer, ovarian cancer, lung cancer, gallbladder cancer, and head and neck cancer.
  • the subject is a mammal; more preferably, the subject is a human.
  • the present invention also provides a method for diagnosing cancer, the method comprising combining the antibody or fragments, nucleic acid molecules, vectors, host cells, pharmaceutical compositions and/or conjugates or fusion proteins of the present invention with a subject Contact with the sample of the person.
  • the cancer is selected from pancreatic cancer, gastric cancer, colon cancer, esophageal cancer, liver cancer, ovarian cancer, lung cancer, gallbladder cancer and head and neck cancer.
  • the subject is a mammal; more preferably, the subject is a human.
  • the coding gene of the anti-human Claudin 18.2 antibody of the present invention was transduced to T cells of primary healthy donors through lentiviral vectors, and it was found that the prepared CART cells can be effectively activated by cells expressing human Claudin 18.2. Therefore, in another aspect, the present invention also provides the use of the antibody or fragments, nucleic acid molecules, vectors, host cells, pharmaceutical compositions and/or conjugates or fusion proteins of the present invention in the preparation of CART cells.
  • the present invention provides a novel antibody capable of specifically binding to human Claudin 18.2. Compared with the existing anti-human Claudin 18.2 antibody, the antibody of the present invention has the following characteristics:
  • the anti-human Claudin 18.2 antibody provided by the present invention has a strong affinity to the antigen Claudin 18.2, and has significant complement-dependent cytotoxicity (CDC) activity and antibody-dependent cytotoxicity (ADCC) activity to target expressing cells, and the The property is stronger than or comparable to IMAB362.
  • CDC complement-dependent cytotoxicity
  • ADCC antibody-dependent cytotoxicity
  • the antibody of the present invention exhibits higher specificity with human CLDN18.2.
  • the coding gene of the anti-human Claudin 18.2 antibody of the present invention is transduced to T cells of primary healthy donors through lentiviral vectors to prepare CART cells. After stimulation of target cells, the surface activation protein CD25 and secreted IFN ⁇ of CART cells were detected, and it was found that the prepared CART cells could be effectively activated by cells expressing human Claudin 18.2, which also proved that the antibody of the present invention is compatible with human CLDN 18.2. Target specificity.
  • antibody refers to an immunoglobulin molecule usually composed of two pairs of polypeptide chains [each pair has a light (L) chain and a heavy (H) chain].
  • a heavy chain can be understood as a polypeptide chain with a larger molecular weight in an antibody
  • a light chain refers to a polypeptide chain with a smaller molecular weight in an antibody.
  • Light chains can be classified into kappa and lambda light chains.
  • Heavy chains can generally be classified as mu, delta, gamma, alpha, or epsilon, and the isotype of the antibody is defined as IgM, IgD, IgG, IgA, and IgE, respectively.
  • variable and constant regions are connected by a "J" region of about 12 or more amino acids, and the heavy chain also includes a "D" region of about 3 or more amino acids.
  • Each heavy chain is composed of a heavy chain variable region (VH) and a heavy chain constant region (CH).
  • the heavy chain constant region is composed of 3 domains (CH1, CH2, and CH3).
  • Each light chain is composed of a light chain variable region (VL) and a light chain constant region (CL).
  • the light chain constant region consists of a domain CL.
  • the constant region of an antibody can mediate the binding of immunoglobulins to host tissues or factors, including various cells of the immune system (for example, effector cells) and the first component (C1q) of the classical complement system.
  • the VH and VL regions can also be subdivided into hyperdenaturation regions [called complementarity determining regions (CDR)], interspersed with more conservative regions called framework regions (FR).
  • CDR complementarity determining regions
  • FR framework regions
  • Each VH and VL is composed of 3 CDRs and 4 FRs arranged in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4 from the amino terminal to the carboxy terminal.
  • the variable regions (VH and VL) corresponding to each heavy chain/light chain respectively form the antibody binding site.
  • the allocation of amino acids to each region or domain follows Kabat EA. Et al., Sequences of Proteins of Immunological Interest [National Institutes of Health, Bethesda, Md. (1987 and 1991)], or Chothia & Lesk 1987)].
  • the heavy chain may also include more than 3 CDRs, such as 6, 9 or 12 CDRs.
  • the heavy chain may be the N-terminus of the heavy chain of an IgG antibody connected to the ScFv of another antibody. In this case, the heavy chain contains 9 CDRs.
  • antigen-binding fragment of an antibody refers to a polypeptide comprising a fragment of a full-length antibody, which retains the ability to specifically bind to the same antigen to which the full-length antibody binds, and/or competes with the full-length antibody for specific binding to the antigen, It is also called the "antigen binding portion”.
  • Antigen-binding fragments of antibodies can be produced by recombinant DNA technology or by enzymatic or chemical cleavage of intact antibodies.
  • antigen-binding fragments include Fab, Fab', F(ab')2, Fd, Fv, dAb, and complementarity determining region (CDR) fragments, single-chain binding fragments (e.g., scFv), chimeric antibodies, double An antibody (diabody) and such a polypeptide comprising at least a portion of an antibody sufficient to confer specific antigen binding ability to the polypeptide.
  • CDR complementarity determining region
  • Fv means an antibody fragment consisting of the VL and VH domains of one arm of an antibody
  • Fab means an antibody fragment consisting of VL, VH, CL and CH1 (or CH) domains
  • F( ab')2 means an antibody fragment comprising two Fab fragments connected by a disulfide bridge on the hinge region.
  • the antigen-binding fragment of an antibody is a single-chain binding fragment (e.g., scFv), in which the VL and VH domains pair to form a monovalent molecule by allowing it to be produced as a linker of a single polypeptide chain [see, e.g., Bird et al. Human, Science 242: 423-426 (1988) and Huston et al., Proc. Natl. Acad. Sci. USA 85: 5879-5883 (1988)].
  • scFv molecules may have the general structure: NH2-VL-linker-VH-COOH or NH2-VH-linker-VL-COOH.
  • Suitable prior art linkers consist of a repetitive G4S amino acid sequence or variants thereof.
  • a 4 linker having an amino acid sequence can be used, but variants thereof can also be used [Holliger et al. (1993), Proc. Natl. Acad. Sci. USA 90: 6444-6448].
  • antibody includes not only intact antibodies, but also antigen-binding fragments of antibodies.
  • isolated refers to those obtained from the natural state by artificial means. If a certain "isolated” substance or component appears in nature, it may be that the natural environment in which it is located has changed, or the substance has been isolated from the natural environment, or both. For example, a certain unisolated polynucleotide or polypeptide naturally exists in a living animal, and the same high-purity polynucleotide or polypeptide isolated from this natural state is called isolation. of.
  • isolated or “isolated” does not exclude the mixing of artificial or synthetic materials, nor does it exclude the presence of other impure materials that do not affect the activity of the material.
  • host cell refers to a cell that can be used to introduce a vector, which includes, but is not limited to, prokaryotic cells such as Escherichia coli, fungal cells such as yeast cells, insect cells such as S2 fruit fly cells or Sf9, or Fibroblasts, CHO cells, COS cells, NSO cells, HeLa cells, BHK cells, HEK 293 cells or human cells and other animal cells.
  • prokaryotic cells such as Escherichia coli
  • fungal cells such as yeast cells
  • insect cells such as S2 fruit fly cells or Sf9
  • Fibroblasts CHO cells, COS cells, NSO cells, HeLa cells, BHK cells, HEK 293 cells or human cells and other animal cells.
  • KD refers to the dissociation equilibrium constant (KD) of a specific antibody-antigen interaction, which is used to describe the binding affinity between the antibody and the antigen.
  • KD dissociation equilibrium constant
  • the antibody binds to the antigen with a dissociation equilibrium constant of less than about 10-5M, for example, less than about 10-6M, 10-7M, 10-8M, 10-9M, or 10-10M or less, for example, as using surface plasmon Resonance technique (SPR) is measured in BIACORE instrument.
  • SPR surface plasmon Resonance technique
  • Antibodies include but are not limited to polyclonal, monoclonal, chimeric, dAb (domain antibody), single chain, Fab, Fab' and F(ab')2 fragments, Fv, scFv and Fab expression libraries.
  • Monoclonal antibody (mAb) is an antibody obtained from a single cloned cell line, and the cell line is not limited to eukaryotic, prokaryotic or phage cloned cell lines.
  • Monoclonal antibodies or antigen-binding fragments can be obtained by recombination using, for example, hybridoma technology, recombination technology, phage display technology, and synthesis technology such as CDR grafting or other existing technologies.
  • the "murine antibody” of the present invention is a monoclonal antibody to human CLDN 18.2 prepared according to the knowledge and skills in the field. During the preparation, the test subject is injected with CLDN18.2 antigen, and then hybridomas expressing antibodies with the desired sequence or functional properties are isolated.
  • the "chimeric antibody” of the present invention is an antibody formed by fusing the variable region of a murine antibody with the constant region of a human antibody, which can reduce the immune response induced by the murine antibody.
  • To establish a chimeric antibody it is necessary to first establish a hybridoma secreting murine-specific monoclonal antibodies, and then clone the variable region genes from the mouse hybridoma cells, and then clone the constant region genes of the human antibody as needed.
  • the gene and the human constant region gene are connected to form a chimeric gene and then inserted into an expression vector, and finally the chimeric antibody molecule is expressed in a eukaryotic industrial system or a prokaryotic industrial system.
  • the "humanized antibody” of the present invention is also called a CDR grafted antibody, and is an antibody produced by grafting mouse CDR sequences into a human antibody variable region framework (FR).
  • Such variable region framework sequences can be obtained from public DNA databases or public references, for example, from the ImmunoGeneTics (IMGT) website http://imgt.cines.fr or from the Journal of Immunoglobulin, 2001ISBN012441351.
  • CLDN18.2 includes isotypes, mammalian (e.g., human) CLDN18.2, species homologs of human CLDN18.2, and analogs containing at least one common epitope with CLDN18.2.
  • CLDN18.2 ( For example, the amino acid sequence of human CLDN18.2) is known in the art, as shown in the NCBI database.
  • CLDN18.1 includes isotypes, mammalian (e.g., human) CLDN18.1, species homologs of human CLDN18.1, and analogs containing at least one common epitope with CLDN18.1.
  • the amino acid sequence of CLDN18.1 (for example, human CLDN18.1) is known in the art, as shown in the NCBI database.
  • composition means a mixture containing one or more of the compounds of the present invention or their physiologically/pharmaceutically acceptable salts or prodrugs and other chemical components, as well as other components such as physiologically/pharmaceutically acceptable Carriers and excipients.
  • the purpose of the pharmaceutical composition is to promote the administration to the organism, which is beneficial to the absorption of the active ingredient and thus the biological activity.
  • the therapeutic composition should generally be sterile and stable under the conditions of manufacture and storage.
  • the composition can be formulated as a solution, microemulsion, dispersion, liposome, or other ordered structure suitable for high antibody concentration.
  • Sterile injectable solutions can be prepared by incorporating the active compound (ie antibody or antibody portion) in the required amount together with one of the ingredients or combinations of ingredients listed above in a suitable solvent, as required, followed by filtration and sterilization. .
  • the method, composition, and combination therapy of the present invention can be combined with other active agents or treatment methods.
  • the method includes administering the anti-CLDN18 of the present invention to a subject in an amount effective to treat or prevent a disease (for example, cancer).
  • a disease for example, cancer
  • .2 Antibody molecule optionally, with PD-1, PD-L1, PD-L2, LAG-3, CTLA-4, Tim-3 antibody (immunotherapy) or other tumor treatment antibodies, Her-2, EGFR, VEGF, VEGFR antibodies, etc., as well as ADC (antibody drug coupling, such as T-DM1), bispecific antibodies, a combination of one or more inhibitors of chemotherapeutics, etc., also including the administration of anti-CLDN18.2 antibody molecules, additional
  • the active agents or all may be administered in an amount or dose that is higher, lower than, or equal to the amount or dose of each active agent used alone (e.g., as a monotherapy).
  • the additional active agent or the total amount or dose administered is lower than the amount or dose of each active agent used alone (for example, as a monotherapy) (for example, at least 20%, at least 30%, at least 40%). % Or at least 50%).
  • the anti-CLDN18.2 antibody of the present invention can combine with CLDN18.2 to induce apoptosis of target cells (tumor cells), inhibit tumor cell growth, and increase the ADCC and CDC killing effects of effector cells on tumor cells in vivo to achieve the purpose of treating cancer patients. Therefore, in certain embodiments, the anti-CLDN18.2 antibody molecules described in the present invention exhibit anti-tumor effects of the antibodies of the present invention through these mechanisms. And a method for inhibiting the growth of tumor cells, comprising administering a therapeutically effective amount of the anti-CLDN18.2 antibody molecule of the present invention to the subject. This method is suitable for in vivo treatment of cancer.
  • the anti-CLDN18.2 antibody molecule can be administered together with other antibodies.
  • the combination can be administered in any order or simultaneously with cancer types, especially tumor patients with high expression of CLDN18.2.
  • methods are provided for treating (e.g., reducing or alleviating) a hyperproliferative condition or disease (e.g., cancer) in a subject in a subject, e.g., solid tumors, hematological cancers, soft tissue tumors, or metastatic lesions.
  • the method includes administering one or more anti-CLDN18.2 antibody molecules of the present invention to the subject alone or in combination with other active agents or treatment modalities.
  • cancer cancer
  • cancer patient are meant to include all types of cancerous growths or tumorigenic processes, metastatic tissues or malignantly transformed cells, tissues or organs, regardless of histopathological type or aggressive stage What is it. Examples include, but are not limited to, solid tumors, hematological cancers, soft tissue tumors, and metastatic lesions.
  • solid tumors include malignant tumors, for example, sarcomas and cancers of multiple organ systems (including adenocarcinoma and squamous cell carcinoma), such as invasion of the liver, lung, breast, lymph, gastrointestinal (for example, colon), genitourinary Tract (e.g., kidney, bladder epithelial cells), prostate, and pharynx.
  • Adenocarcinoma includes malignant tumors such as most colon cancers, rectal cancers, stomach cancers, renal cell carcinomas, liver cancers, non-small cell carcinomas among lung cancers, small bowel cancers, and esophageal cancers.
  • Squamous cell carcinoma includes malignant tumors, such as in the lungs, esophagus, skin, head and neck area, oral cavity, anus, and cervix.
  • the aforementioned metastatic lesions of cancer can also be treated or prevented using the methods and compositions of the present invention.
  • Antibody molecules directed against CLDN18.2 can be combined with immunogenic agents such as cancer cells, purified tumor antigens (including recombinant proteins, peptides, and sugar molecules), cells, and cells transfected with genes encoding immunostimulatory cytokines.
  • immunogenic agents such as cancer cells, purified tumor antigens (including recombinant proteins, peptides, and sugar molecules), cells, and cells transfected with genes encoding immunostimulatory cytokines.
  • ADCC antibody-dependent cell-mediated cytotoxicity
  • effector cells especially lymphocytes
  • FcR Fc receptors
  • Several Fc receptor families have been identified, and specific cell populations characteristically express defined Fc receptors.
  • ADCC can be regarded as a mechanism that directly induces variable degrees of immediate tumor destruction that leads to antigen presentation and induces tumor-directed T cell responses.
  • the in vivo induction of ADCC will result in a tumor-targeted T cell response and a host-derived antibody response.
  • complement dependent cytotoxicity is another method of cell killing that can be directed by antibodies.
  • IgM is the most effective isotype for complement activation.
  • IgG1 and IgG3 are also very effective in directing CDC through the classical complement activation pathway.
  • C1q is the three subgroups of complement C1.
  • these exposed C1q binding sites convert the previously low-affinity C1q-IgG interaction into a high-affinity interaction, which triggers a cascade of events involving a series of other complement proteins and leads to the effector cell chemotaxis/activator C3a And C5a is released by proteolysis.
  • the complement cascade ends with the formation of a membrane attack complex that creates pores in the cell membrane that facilitate the free entry and exit of water and solutes from the cell.
  • the antibody-drug conjugate prepared by the anti-CLDN18.2 antibody herein can mediate by inducing complement-dependent cytotoxicity (CDC)-mediated lysis and/or antibody-dependent cellular cytotoxicity (ADCC).
  • CDC complement-dependent cytotoxicity
  • ADCC antibody-dependent cellular cytotoxicity
  • the antibody-drug conjugate of the present invention induces complement-dependent cytotoxicity (CDC)-mediated lysis and/or antibody-dependent cellular cytotoxicity (ADCC)-mediated lysis (preferably Cell killing is mediated by inducing CDC-mediated lysis and ADCC-mediated lysis).
  • Figure 1 shows the results of in vitro cell binding experiments of the anti-human CLDN18.2 chimeric antibody.
  • Figure 2 shows the results of the complement-dependent cytotoxicity (CDC) experiment of the anti-human CLDN18.2 humanized antibody, where 2A: CHOK1; 2B: BxPC3; 2C: NCI-N87.
  • Figure 3 shows the results of the antibody-dependent cytotoxicity (ADCC) experiment of the anti-human CLDN18.2 humanized antibody, in which 3A: CHOK1; 3B: BxPC3; 3C: NCI-N87.
  • ADCC antibody-dependent cytotoxicity
  • Figure 4 shows the analysis results of the homologous protein binding characteristics of the anti-human CLDN18.2 humanized antibody.
  • Figure 5 shows the binding of anti-human CLDN18.2 humanized antibodies to human CLDN18.1 expressing cells at different concentrations.
  • Figure 6 shows the analysis results of the species cross-binding characteristics of the anti-human CLDN18.2 humanized antibody.
  • Figure 7 shows the positive rate test results of the prepared CART cells in each group.
  • Figure 8 shows the expression of different antigens of the constructed CHO cell lines.
  • Figure 9 shows the detection results of IFN- ⁇ in the supernatant of each group of CART cells and target cells after incubation.
  • Figure 10 shows the detection results of CD25 expression after each group of CART cells are incubated with target cells.
  • IMAB362 For the heavy chain and light chain sequences of IMAB362, please refer to SEQ ID NO: 126 and SEQ ID NO: 127.
  • the negative control Isotype control in the figure is the anti-CD33 full-length IgG antibody Lintuzumab.
  • mice were immunized with CHOK1 cells stably expressing the human CLDN18.2 protein on the cell surface.
  • the mouse serum was analyzed by flow cytometry (FACS), and the spleens of mice with high serum antibody titers were taken.
  • the spleen cells isolated by standard methods are fused with myeloma cells P3X63Ag8.653 using PEG or electrofusion methods.
  • the fused hybridoma cells were seeded in a 384-well plate, and after culturing for 10-14 days, the supernatant was used to analyze the antibodies secreted by the hybridoma cells by FACS, and several clones were screened, which can bind to the cell surface to stably express human CLDN18. 2 protein CHOK1 cells cannot bind to CHOK1 cells stably expressing human CLDN18.1 protein on the cell surface. The selected clones were single-celled by the limiting dilution method, and each hybridoma clone obtained after 3 rounds secreted only one antibody.
  • the total RNA of the cells is extracted according to the instructions of the RNAfast200 kit (Shanghai Feijie Biotechnology Co., Ltd.); the hybridoma cells are extracted using 5 ⁇ PrimeScript RT Master Mix (Takara) Reverse transcription of total RNA into cDNA; use degenerate primers (Anke Krebber.
  • VH Light chain variable region
  • VL Light chain variable region
  • VL Light chain variable region
  • VL Light chain variable region
  • SEQ ID NO: 1 SEQ ID NO: 2 16K15 SEQ ID NO: 3 SEQ ID NO: 4 18B21 SEQ ID NO: 5 SEQ ID NO: 6 20L17 SEQ ID NO: 7 SEQ ID NO: 8 43B5 SEQ ID NO: 9 SEQ ID NO: 10 43L6 SEQ ID NO: 11 SEQ ID NO: 12 46J05 SEQ ID NO: 13 SEQ ID NO: 14 48G12 SEQ ID NO: 15 SEQ ID NO: 16 50C14 SEQ ID NO: 17 SEQ ID NO: 18 52E22 SEQ ID NO: 19 SEQ ID NO: 20 8K13 SEQ ID NO: 21 SEQ ID NO: 22
  • the heavy chain variable region sequence of the mouse-derived anti-human CLDN18.2 monoclonal antibody and the publicly published heavy chain constant region sequence of the human monoclonal antibody IgG1 subclass were spliced together to construct a lactation In an animal cell expression vector; the light chain variable region sequence of the mouse-derived anti-human CLDN18.2 monoclonal antibody and the publicly published light chain constant region sequence of the human monoclonal antibody ⁇ subclass (see SEQ ID NO: 125) Together, they are constructed into mammalian cell expression vectors.
  • the constructed anti-human CLDN18.2 chimeric antibody heavy chain vector and light chain vector were paired and mixed, and HEK293 cells were transfected with polyethyleneimine (PEI). After about 7 days, the cell supernatant was collected and purified by ProteinA to obtain anti-human CLDN18 .2 Chimeric antibody protein.
  • PEI polyethyleneimine
  • the chimeric antibody of the present invention is named "murine antibody for short -xiIgG".
  • the amino acid sequence regions of the six antigen complementarity determinants (CDR) of the heavy and light chains of the murine antibody and the framework region supporting the conservative three-dimensional conformation of the antibody are determined. Then through analysis and search of known human antibody sequences, select the human antibody heavy chain variable region sequence that is most similar to the mouse antibody, such as IGHV1
  • the antibody whose CDR of murine antibody is directly transplanted to the human framework region often has a sharp decrease in binding activity, so it is necessary to change individual amino acids of the framework region from human origin back to murine origin.
  • To determine the back mutation site one is to compare the designed humanized antibody sequence with the original murine antibody sequence to check which amino acids are different; the other is to check whether these amino acids play an important role in supporting the structure of the antibody or whether it is related to the antigen Combination plays an important role.
  • the humanized design sequence needs to be checked for some potential post-translational modification sites (PTM), such as N (asparagine) glycosylation site, N deamidation site, D (asparagine) Acid) isomerization sites, etc.
  • PTM post-translational modification sites
  • the humanized antibody heavy chain variable region gene was constructed into a mammalian cell expression vector containing the heavy chain constant region gene of the human monoclonal antibody IgG1 subclass; the light chain variable region gene was constructed into the human monoclonal antibody ⁇ subclass Class of light chain constant region genes in mammalian cell expression vectors.
  • the constructed anti-human CLDN18.2 humanized antibody heavy chain vector and light chain vector are paired and mixed, and HEK293 cells are transfected with polyethyleneimine (PEI). After about 7 days, the cell supernatant is collected and purified with ProteinA to obtain the anti-human CLDN18.2 humanized antibody protein.
  • PEI polyethyleneimine
  • the humanized antibody of the present invention is named "murine antibody for short -hz".
  • the antibody in which the CDR of murine antibody is directly transplanted to the human framework region is named "mouse antibody for short-hz00".
  • the antibodies obtained by further modification are numbered according to different sequences.
  • the dissociation constant values of the remaining 8K13-hz24, 16K15-hz22 and 52E22-hz12 are 1-4 times higher than the original mouse chimeric antibody, and can be selected as the lead molecule to continue the follow-up research.
  • the 16K15-hz22 light chain amino acid sequence contains two consecutive "NN” residues.
  • the 16K15-hz22_2 and 16K15-hz22_3 mutant antibodies have been further optimized, and the "NN” residues have been changed to "SN" and "QN” respectively. "Residues.
  • a GE BIAcore instrument S200 was used to determine the antibody-antigen interaction.
  • the sensor chip CM5 analysis channel and the control sample channel are both saturated and coupled with the maximum amount of anti-human Fc antibody, and then flow through the analysis channel containing 7.5 ⁇ g/ml anti-human CLDN18.2 chimeric antibody, humanized antibody or control antibody IMAB362 buffer to make it evenly distributed, and finally flow through the gradient dilution antigen sample (initial concentration 20nM) in the analysis channel and the control sample channel. , 1:3 dilution of 8 concentration points, and set 0.741nm concentration point to repeat), measure the light reaction value after the antibody antigen binding. After fitting and analysis by the instrument software, the binding constant Kon and dissociation constant Koff of the antibody, and the affinity constant KD are finally obtained.
  • the humanized antibody of the present invention was analyzed using Quidel's commercial human serum complete complement, and its ability to induce complement dependent cytotoxicity (CDC) on CHOK1, BxPC3 and NCI-N87 cells stably expressing human CLDN18.2 was analyzed.
  • CDC complement dependent cytotoxicity
  • Target expressing cell a.CHOK1 b.BxPC3 c. NCI-N87 Antibody EC50(nM) EC50(nM) EC50(nM) 8K13-hz24 IgG 21.27 28.53 57.7 16K15-hz22 IgG 5.2 12.22 17.36 52E22-hz12 IgG 2.08 NA NA IMAB362 30.45 52.23 474.2
  • ADCC Antibody Dependent Cytotoxicity
  • the engineered Jurkat cells are used as effector cells, which stably express the Fc ⁇ RIIIa-Fc ⁇ RIa ⁇ hybrid receptor, and are driven by the NFAT response element to express firefly luciferase.
  • the biological activity of the antibody in the ADCC mechanism of action is quantified by the luciferase produced by the activation of the NFAT pathway.
  • Target expressing cell a.CHOK1 b.BxPC3 c. NCI-N87 Antibody EC50(nM) EC50(nM) EC50(nM) 8K13-hz24 IgG 0.5894 0.3045 0.1499 16K15-hz22 IgG 0.7122 0.1759 0.0677 52E22-hz12 IgG 0.5672 NA NA IMAB362 0.5929 0.1056 0.0909
  • the genes of human CLDN18.2 and CLDN18.1 were respectively constructed into eukaryotic expression vectors, and HEK293 cells were transfected with polyethyleneimine (PEI). On the third day after transfection, the cells were collected by centrifugation, washed with PBS once, and resuspended at a cell density of 2 ⁇ 10 6 /ml. Add 10ul of cells to each 384-well plate; in the second step, add different cells to the 384-well plate.
  • PEI polyethyleneimine
  • the CLDN18.2 genes of human, mouse and rhesus monkey (Rhesus) were respectively constructed into eukaryotic expression vectors, and HEK293 cells were transfected with polyethyleneimine (PEI), and the cells were collected 2 days later.
  • PEI polyethyleneimine
  • Flow cytometry was used to analyze the binding specificity of the cells and the anti-human CLDN18.2 humanized antibody. Refer to Example 7 for the flow cytometry experiment method.
  • lentivirus packaging was carried out. Firstly, the lentiviral vector plasmid pLTR containing different antibody genes was constructed. After the sequencing was correct, their plasmid DNA was extracted using Qiagen's plasmid extraction kit. The plasmid DNA was dissolved in sterilized TE, and its concentration was determined by ultraviolet light absorption method. And purity, to ensure that the A260/A280 of the plasmid DNA is between 1.8 and 2.0. The DNA of two auxiliary packaging element vector plasmids pCMV-VSV-G and pCMV-dR8.2 was extracted at the same time.
  • the HEK293T cells to be used for transfection need to be passaged fresh and grown to about 60% confluence.
  • calcium phosphate as a transfection reagent, the three plasmids were co-transformed into HEK293T cells.
  • the cell supernatant containing the packaged virus was collected by low-temperature centrifugation, and a 0.45 ⁇ m filter was used to remove cell debris.
  • Use an ultrafiltration centrifuge tube to concentrate the virus and change the solution, and store it in a -80°C refrigerator after aliquoting. Take a small amount of virus concentrate and use FACS method to determine the virus titer.
  • the negative control in Table 7 is other antibodies that do not bind to CLDN18.2, and the positive control is Keji Bio-hu8E5 antibody (see WO2018006882A1). *The single-chain antibody shown is the corresponding humanized VH and VL connected by short peptides (GSTSGGGSGGGSGGGGSS).
  • the cell density is adjusted to 1.0E+06/ml, and centrifuged at 500g for 30min. Afterwards, stand in a CO 2 incubator at 37°C for 48 hours.
  • CHO was used to construct cells expressing human CLDN18.1 antigen and human CLDN18.2 antigen as target cells.
  • CHO-BLANK blank control
  • CHO-CLDN18.1 have no CLDN18.2 antigen expression
  • CHO-CLDN18.2 highly express CLDN18.2 antigen.

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Abstract

本发明提供一种结合人Claudin18.2的抗体或其片段，以及它们的编码核酸等。本发明的抗人Claudin18.2抗体对抗原Claudin18.2具有强亲和力，对靶点表达细胞具有显著的补体依赖性细胞毒(CDC)活性和抗体依赖性细胞毒(ADCC)活性，并且表现出与人CLDN18.2的高特异性。

Description

抗人Claudin18.2抗体及其应用
本专利申请要求于2019年9月29日提交的申请号为CN201910929614.0的中国发明专利申请的优先权权益，在此将其全部内容引入作为参考。
技术领域
本发明属于生物医药领域，涉及一种新的抗人Claudin18.2抗体或其功能性片段。本发明还涉及所述抗体或其功能性片段的应用。
背景技术
人紧密连接蛋白Claudin18(CLDN18)属于密连接蛋白家族，这类蛋白生物学上在构建细胞紧密连接、维持细胞屏障功能和参与细胞间分子传递等方面发挥作用。Claudin18蛋白分子量约26KD，可以通过选择性剪接使Claudin蛋白变成具有不同特性的Claudin亚型：CLDN18.1和CLDN18.2。CLDN18.1和CLDN18.2均由261个氨基酸组成，均具有四个跨膜结构域，NH2端和COOH端位于胞内，具有两个胞外环(ExtracellularLoops：ECL1，ECL2)。CLDN18.1和CLDN18.2胞外区1中仅存在8个氨基酸差别。
其中CLDN18.2在多种人上皮肿瘤类型的原发病灶和转移灶中表达，并在弥散性癌细胞中持续表达。在食管癌、胰腺癌、肺癌和胃癌细胞中，CLDN18.2的表达水平更是有显著的增高。Sahin等人研究认为CLDN18.2是个重要的胃癌生物标志物，它存在于70％的胃癌病人中，其中90％至95％被诊断为腺癌，另外5-10％包括淋巴瘤、胃肠道间质瘤(GIST)和类癌肿瘤。
德国的生物科技公司Ganymed开发了一种针对CLDN18.2的单克隆抗体IMAB362，目前处于临床III期临床试验中，用于治疗胃食管癌晚期患者。单独的IMAB362抗体结合在体外和体内均导致表达CLDN18.2的靶细胞的增殖抑制，其抑制肿瘤生长和清除癌细胞作用机制一是通过补体依赖的细胞毒性作用(CDC)，二是抗体依赖的细胞毒性作用(ADCC)，各种作用模式被证明独立存在但有协同作用。IMAB362抗体针对转移性食管癌、转移性胃癌适应症，目前美国和欧盟处于临床3期，预期将于2021年申请上市。
然而，IMAB362是一个嵌合抗体，还有较多的鼠源氨基酸，在人体内引起排斥免疫反应的概率相对比较高。因此，本领域仍然存在对人CLDN18.2 具有更高特异性、亲和力和生物活性的抗体、特别是人源化抗体的需要。此外，Claudin18的两个亚型CLDN18.1和CLDN18.2结构高度相似，而功能却不相同，CLDN18.1和CLDN18.2的高度同源性及ECL1存在高级结构，筛选针对CLDN18.2的高质量抗体具有较大的难度，在抗体特异性方面存在高度的不确定性。
发明内容
本发明要解决的技术问题是，通过单克隆抗体制备方法的优化，提高Claudin18.2特异性抗体的筛选效率，通过杂交瘤筛选和人源化技术，获得特异性结合人CLDN18.2的高亲和力抗体，其中通过人源化设计，该抗体最大程度减少了鼠源氨基酸的数目，预期拥有更好的体内安全性和应用前景。
针对上述技术问题，从免疫原方面，本发明采用了鼠源细胞表达人CLDN18.2。一方面，作为宿主的鼠源细胞对小鼠不具备免疫原性或具有极低的免疫原性，从而避免了宿主细胞对目的免疫原CLDN18.2的遮蔽效应，避免因引入异源免疫原导致的对CLDN18.2特异性杂交瘤产生效率的不良影响；另一方面，以鼠源细胞表达人CLDN18.2可以实现膜表面表达，使筛选获得的单克隆抗体特异性结合CLDN18.2的胞外区，确保了CLDN18.2特异性抗体的生物活性。
从筛选从策略方面，本发明采用了正反向筛选相结合的策略。首先，利用表达人CLDN18.2的重组细胞进行正向筛选，获得对其具有高亲和力的单抗克隆；然后，对于能够以高亲和力结合人CLDN18.2重组细胞的抗体克隆，进一步利用表达人CLDN18.1的重组细胞进行反向筛选，反向筛选能排除特异性结合CLDN18.2、CLDN18.1共同胞外区结构的单抗。此外，本发明使用的免疫原、正向筛选抗原、反向筛选抗原采用的均是相同的鼠源细胞平台，不仅简化了方法、避免了引入异种抗原，而且能够通过反向筛选步骤消除因鼠源细胞对小鼠个体的同种异体抗原效应而产生的抗体，进一步提高特异性结合CLDN18.2的胞外区2的单克隆抗体制备效率。
本发明的另一目的是提供一种特异性结合人CLDN18.2的抗体或其片段，并提供其用途。其中，本发明所述的抗体的片段涵盖抗体的各种功能性片段，例如其抗原结合部分，如Fab、F(ab’) 2或scFv片段。
本发明的技术方案如下。
一方面，本发明提供一种抗人Claudin18.2抗体的制备方法，包括：
(1)利用表面表达人Claudin18.2蛋白的细胞作为免疫原免疫动物；
(2)利用步骤(1)中经过免疫的动物制备能产生抗体的细胞克隆；
(3)利用表面表达人Claudin18.2蛋白的细胞作为正向筛选抗原，筛选对其具有结合活性的抗体及其产生细胞；
(4)利用表面表达人Claudin18.1蛋白的细胞作为反向筛选抗原，排除对其具有结合活性的抗体及其产生细胞。
优选的，本发明所述的制备方法，所述步骤(1)中表达人Claudin18.2蛋白的细胞源自与所述被免疫动物相同的物种，优选所述表达人Claudin18.2蛋白的细胞为小鼠细胞、所述被免疫动物为小鼠。
优选的，本发明所述的制备方法，所述步骤(2)中选自以下技术制备能产生抗体的细胞克隆：杂交瘤技术、单细胞扩增技术。
优选的，本发明所述的制备方法，所述步骤(3)中的正向筛选抗原与步骤(1)中的免疫原相同；所述步骤(4)中的反向筛选抗原与步骤(1)中免疫原的区别仅在于所述表达的蛋白为人Claudin18.1。
优选的，本发明所述的制备方法，所述步骤(3)、(4)采用选自以下的方法进行筛选：酶联免疫法(ELISA)、荧光共振能量转移(FRET)。
另一方面，本发明还提供根据本发明所述抗人Claudin18.2抗体的制备方法获得的抗人Claudin18.2抗体。
优选的，本发明所述的抗人Claudin18.2抗体，其特异性结合人Claudin18.2的N端，优选特异性结合人Claudin18.2 N端的胞外区，包括第一胞外环(Extracellular Loop 1，ECL1)。
优选的，本发明所述的抗人Claudin18.2抗体，其对人CLDN18.2有nM级的特异性结合；并且，其对人CLDN18.1的结合与同种型阴性抗体(或无关抗体)相比无显著差异。
另一方面，本发明提供一种抗体或其片段，所述抗体或其片段包含重链可变区(VH)和轻链可变区(VL)，其中所述重链可变区(VH)和轻链可变区(VL)包含选自以下的CDR组合(VH-CDR1、VH-CDR2、VH-CDR3；VL-CDR1、VL-CDR2、VL-CDR3)：
(1)如SEQ ID NO:31所示的VH-CDR1、如SEQ ID NO:32所示的VH-CDR2、如SEQ ID NO:33所示的VH-CDR3；如SEQ ID NO:34所示的 VL-CDR1、如SEQ ID NO:35所示的VL-CDR2、如SEQ ID NO:36所示的VL-CDR3；
(2)如SEQ ID NO:37所示的VH-CDR1、如SEQ ID NO:38所示的VH-CDR2、如SEQ ID NO:39所示的VH-CDR3；如SEQ ID NO:40所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:42所示的VL-CDR3；
(3)如SEQ ID NO:43所示的VH-CDR1、如SEQ ID NO:44所示的VH-CDR2、如SEQ ID NO:45所示的VH-CDR3；如SEQ ID NO:46所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:47所示的VL-CDR3；
(4)如SEQ ID NO:48所示的VH-CDR1、如SEQ ID NO:49所示的VH-CDR2、如SEQ ID NO:50所示的VH-CDR3；如SEQ ID NO:40所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:51所示的VL-CDR3；
(5)如SEQ ID NO:52所示的VH-CDR1、如SEQ ID NO:53所示的VH-CDR2、如SEQ ID NO:54所示的VH-CDR3；如SEQ ID NO:55所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:56所示的VL-CDR3；
(6)如SEQ ID NO:57所示的VH-CDR1、如SEQ ID NO:58所示的VH-CDR2、如SEQ ID NO:33所示的VH-CDR3；如SEQ ID NO:34所示的VL-CDR1、如SEQ ID NO:59所示的VL-CDR2、如SEQ ID NO:60所示的VL-CDR3；
(7)如SEQ ID NO:61所示的VH-CDR1、如SEQ ID NO:62所示的VH-CDR2、如SEQ ID NO:63所示的VH-CDR3；如SEQ ID NO:46所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:64所示的VL-CDR3；
(8)如SEQ ID NO:65所示的VH-CDR1、如SEQ ID NO:66所示的VH-CDR2、如SEQ ID NO:67所示的VH-CDR3；如SEQ ID NO:68所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:69所示的VL-CDR3；
(9)如SEQ ID NO:65所示的VH-CDR1、如SEQ ID NO:70所示的 VH-CDR2、如SEQ ID NO:71所示的VH-CDR3；如SEQ ID NO:72所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:73所示的VL-CDR3；
(10)如SEQ ID NO:74所示的VH-CDR1、如SEQ ID NO:75所示的VH-CDR2、如SEQ ID NO:76所示的VH-CDR3；如SEQ ID NO:77所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:78所示的VL-CDR3；
(11)如SEQ ID NO:79所示的VH-CDR1、如SEQ ID NO:80所示的VH-CDR2、如SEQ ID NO:81所示的VH-CDR3；如SEQ ID NO:82所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:83所示的VL-CDR3；
(12)如SEQ ID NO:37所示的VH-CDR1、如SEQ ID NO:38所示的VH-CDR2、如SEQ ID NO:39所示的VH-CDR3；如SEQ ID NO:85所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:42所示的VL-CDR3；
(13)如SEQ ID NO:37所示的VH-CDR1、如SEQ ID NO:38所示的VH-CDR2、如SEQ ID NO:39所示的VH-CDR3；如SEQ ID NO:85所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:86所示的VL-CDR3；
(14)如SEQ ID NO:37所示的VH-CDR1、如SEQ ID NO:38所示的VH-CDR2、如SEQ ID NO:39所示的VH-CDR3；如SEQ ID NO:85所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:87所示的VL-CDR3；
(15)如SEQ ID NO:74所示的VH-CDR1、如SEQ ID NO:75所示的VH-CDR2、如SEQ ID NO:76所示的VH-CDR3；如SEQ ID NO:89所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:90所示的VL-CDR3；和
(16)如SEQ ID NO:79所示的VH-CDR1、如SEQ ID NO:91所示的VH-CDR2、如SEQ ID NO:81所示的VH-CDR3；如SEQ ID NO:92所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:93所示的VL-CDR3。
优选地，在本发明提供的抗体或其片段中，所述重链可变区包含：
SEQ ID NO:1、SEQ ID NO:3、SEQ ID NO:5、SEQ ID NO:7、SEQ ID NO:9、SEQ ID NO:11、SEQ ID NO:13、SEQ ID NO:15、SEQ ID NO:17、SEQ ID NO:19、SEQ ID NO:21、SEQ ID NO:23、SEQ ID NO:27和SEQ ID NO:29中任一个所示的氨基酸序列或与所示的氨基酸序列具有至少75％同一性的氨基酸序列；和/或
所述轻链可变区包含：
选自SEQ ID NO:2、SEQ ID NO:4、SEQ ID NO:6、SEQ ID NO:8、SEQ ID NO:10、SEQ ID NO:12、SEQ ID NO:14、SEQ ID NO:16、SEQ ID NO:18、SEQ ID NO:20、SEQ ID NO:22、SEQ ID NO:24、SEQ ID NO:25、SEQ ID NO:26、SEQ ID NO:28、SEQ ID NO:30中任一个所示的氨基酸序列或与所示的氨基酸序列具有至少75％同一性的氨基酸序列。
根据本发明的具体实施方式，所述抗体或其片段包含的重链可变区和轻链可变区选自以下组合：
(1)如SEQ ID NO:1所示的氨基酸序列或与如SEQ ID NO:1所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:2所示的氨基酸序列或与如SEQ ID NO:2所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(2)如SEQ ID NO:3所示的氨基酸序列或与如SEQ ID NO:3所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:4所示的氨基酸序列或与如SEQ ID NO:4所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(3)如SEQ ID NO:5所示的氨基酸序列或与如SEQ ID NO:5所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:6所示的氨基酸序列或与如SEQ ID NO:6所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(4)如SEQ ID NO:7所示的氨基酸序列或与如SEQ ID NO:7所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:8所示的氨基酸序列或与如SEQ ID NO:8所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(5)如SEQ ID NO:9所示的氨基酸序列或与如SEQ ID NO:9所示的氨 基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:10所示的氨基酸序列或与如SEQ ID NO:10所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(6)如SEQ ID NO:11所示的氨基酸序列或与如SEQ ID NO:11所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:12所示的氨基酸序列或与如SEQ ID NO:12所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(7)如SEQ ID NO:13所示的氨基酸序列或与如SEQ ID NO:13所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:14所示的氨基酸序列或与如SEQ ID NO:14所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(8)如SEQ ID NO:15所示的氨基酸序列或与如SEQ ID NO:15所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:16所示的氨基酸序列或与如SEQ ID NO:16所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(9)如SEQ ID NO:17所示的氨基酸序列或与如SEQ ID NO:17所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:18所示的氨基酸序列或与如SEQ ID NO:18所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(10)如SEQ ID NO:19所示的氨基酸序列或与如SEQ ID NO:19所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:20所示的氨基酸序列或与如SEQ ID NO:20所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(11)如SEQ ID NO:21所示的氨基酸序列或与如SEQ ID NO:21所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:22所示的氨基酸序列或与如SEQ ID NO:22所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(12)如SEQ ID NO:23所示的氨基酸序列或与如SEQ ID NO:23所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:24所示的氨基酸序列或与如SEQ ID NO:24所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(13)如SEQ ID NO:23所示的氨基酸序列或与如SEQ ID NO:23所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:25所示的氨基酸序列或与如SEQ ID NO:25所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(14)如SEQ ID NO:23所示的氨基酸序列或与如SEQ ID NO:23所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:26所示的氨基酸序列或与如SEQ ID NO:26所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(15)如SEQ ID NO:27所示的氨基酸序列或与如SEQ ID NO:27所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:28所示的氨基酸序列或与如SEQ ID NO:28所示的氨基酸序列具有至少75％同一性的氨基酸序列；
(16)如SEQ ID NO:29所示的氨基酸序列或与如SEQ ID NO:29所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:30所示的氨基酸序列或与如SEQ ID NO:30所示的氨基酸序列具有至少75％同一性的氨基酸序列。
本发明的上下文中，所述至少75％同一性为例如至少80％、优选至少85％、更优选至少90％、进一步优选至少91％、92％、93％、94％、95％、96％、97％、98％或甚至99％同一性等≥75％的任何百分比的同一性。
本发明提供的抗体或其片段可以为单克隆抗体、单链抗体、双功能抗体、单域抗体、纳米抗体、完全或部分人源化的抗体或者嵌合抗体等任意形式，或者，所述抗体或其片段为半抗体或半抗体的抗原结合片段，例如scFv、BsFv、dsFv、(dsFv) 2、Fab、Fab'、F(ab') 2或Fv；关于本发明提供的抗体的片段，优选地，所述片段为抗体的能够特异性结合人Claudin18.2的任何片段。
优选地，所述抗体或其片段还包含人或鼠的恒定区，优选包含人或鼠的轻链恒定区(CL)和/或重链恒定区(CH)；
更优选地，所述抗体或其片段包含选自IgG、IgA、IgM、IgD或IgE的重链恒定区和/或κ或λ型轻链恒定区。
优选地，所述抗体为单克隆抗体，优选为鼠源、嵌合或人源化的单克隆抗体；更优选地，所述单克隆抗体的重链恒定区为IgG1或IgG4亚型，轻链 恒定区为κ型；
根据本发明的具体实施方式，所述单克隆抗体的重链恒定区包含如SEQ ID NO:124所示的氨基酸序列或者与所述氨基酸序列具有至少75％同一性的氨基酸序列；
根据本发明的具体实施方式，所述单克隆抗体的轻链恒定区包含如SEQ ID NO:125所示氨基酸序列或者与所述氨基酸序列具有至少75％同一性的氨基酸序列。
另一方面，本发明提供一种核酸分子，其编码本发明所述的抗体或其片段或者编码所述抗体或其片段中包含的重链CDR、轻链CDR、轻链可变区、重链可变区、重链或轻链。
根据本发明的具体实施方式，所述核酸分子编码本发明所述的抗体或其片段中的重链可变区或轻链可变区，例如，所述核酸分子包含如SEQ ID NOs:96-125中任一个所示的核苷酸序列。
本发明的核酸分子可以被克隆到载体中，进而转化或转染宿主细胞。因此，还一方面，本发明提供一种载体，其包含本发明的核酸分子。所述载体可以为真核表达载体、原核表达载体、人工染色体及噬菌体载体等。
本发明的载体或核酸分子可以用于转化或转染宿主细胞或以任何方式进入宿主细胞内，用于保存或表达抗体等目的。因此，又一方面，本发明提供一种宿主细胞，所述宿主细胞包含本发明的核酸分子和/或载体，或者所述宿主细胞被本发明的核酸分子和/或载体转化或转染。宿主细胞可以是任何原核或真核细胞，例如细菌或昆虫、真菌、植物或动物细胞。
本发明提供的抗体可以利用本领域已知的任何方法获得。例如，可以先由本发明提供的核酸分子获得所述抗体的重链可变区和/或轻链可变区，或者获得所述抗体的重链和/或轻链，然后与所述抗体的任选其他结构域组装成抗体；或者，在允许本发明提供的宿主细胞表达所述抗体的重链可变区和/或轻链可变区或者所述抗体的重链和/或轻链以组装成所述抗体的情况下，培养所述宿主细胞。任选地，所述方法还包括回收产生的抗体的步骤。
本发明提供的抗体或其片段还可与其他部分结合，例如细胞表面受体、小分子化合物如氨基酸和糖类、小分子聚合物或对本发明所述抗体进行修饰的任何其它部分，或者甚至是活性蛋白或多肽。因此，另一方面，本发明提供一种缀合物或融合蛋白，其包含本发明提供的抗体或其片段。例如，该缀 合物或融合蛋白可以是包含本发明所述抗体或其片段的双特异性抗体。
本发明提供的抗体或其片段、核酸分子、载体、宿主细胞和/或缀合物或融合蛋白可以被包含在药物组合物中，更特别地被包含在药物制剂中，从而根据实际需要用于各种目的。因此，在又一方面，本发明还提供一种药物组合物，所述药物组合物包含本发明所述的抗体或其片段、核酸分子、载体、宿主细胞和/或缀合物或融合蛋白，以及可选的药学上可接受的辅料。
出于任何使用目的，本发明还提供一种试剂盒，所述试剂盒包括本发明的抗体分子或其片段、核酸分子、载体、宿主细胞、药物组合物和/或缀合物或融合蛋白。
另一方面，本发明提供上述抗体或其片段、核酸分子、载体、宿主细胞、药物组合物和/或缀合物或融合蛋白在制备用于预防和/或治疗癌症的药物中的用途。优选地，所述癌症选自胰腺癌、胃癌、结肠癌、食管癌、肝癌、卵巢癌、肺癌、胆囊癌和头颈癌。
再一方面，本发明还提供所述抗体或其片段、核酸分子、载体、宿主细胞、药物组合物和/或缀合物或融合蛋白在制备用于诊断癌症的试剂中的用途。优选地，所述癌症选自胰腺癌、胃癌、结肠癌、食管癌、肝癌、卵巢癌、肺癌、胆囊癌和头颈癌。
另一方面，本发明还提供一种预防和/或治疗癌症的方法，所述方法包括给有此需要的受试者施用本发明的抗体或其片段、核酸分子、载体、宿主细胞、药物组合物和/或缀合物或融合蛋白，以及任选的其他药物或手段。该任选的其他药物或手段是指可以与本发明抗体或其片段、核酸分子、载体、宿主细胞、药物组合物和/或缀合物或融合蛋白联合施用的其他药物或手段，例如小分子化药、靶向药、抗体等重组蛋白药、疫苗、ADC、溶瘤病毒、基因和核酸治疗药物和放射疗法。二者的联合施用可以采取任意形式进行，例如同时、连续或间隔一定时间进行。
优选地，所述癌症选自胰腺癌、胃癌、结肠癌、食管癌、肝癌、卵巢癌、肺癌、胆囊癌和头颈癌。优选地，所述受试者为哺乳类动物；更优选地，所述受试者为人。
或者，本发明还提供一种诊断癌症的方法，所述方法包括使本发明的抗体或其片段、核酸分子、载体、宿主细胞、药物组合物和/或缀合物或融合蛋白与来自受试者的样品相接触。优选地，所述癌症选自胰腺癌、胃癌、结肠 癌、食管癌、肝癌、卵巢癌、肺癌、胆囊癌和头颈癌。优选地，所述受试者为哺乳类动物；更优选地，所述受试者为人。
将本发明的抗人Claudin18.2抗体的编码基因通过慢病毒载体转导到原代健康供者的T细胞上，发现所制备的CART细胞能够被表达人Claudin18.2的细胞有效活化。因此，还一方面，本发明还提供本发明的抗体或其片段、核酸分子、载体、宿主细胞、药物组合物和/或缀合物或融合蛋白在制备CART细胞中的用途。
本发明提供了一种新型的能够特异性结合人Claudin18.2的抗体。与现有抗人Claudin18.2抗体相比，本发明的抗体具有以下特点：
本发明提供的抗人Claudin18.2抗体对抗原Claudin18.2具有强亲和力，对靶点表达细胞具有显著的补体依赖性细胞毒(CDC)活性和抗体依赖性细胞毒(ADCC)活性，且所述性质强于IMAB362或与其相当。此外，与IMAB362相比，本发明的抗体表现出与人CLDN18.2更高的特异性。
此外，将本发明的抗人Claudin18.2抗体的编码基因通过慢病毒载体转导到原代健康供者的T细胞上，制备CART细胞。经靶细胞刺激后，检测CART细胞的表面活化蛋白CD25和分泌的IFNγ，发现制得的CART细胞能够被表达人Claudin18.2的细胞有效活化，同样证明了本发明的抗体与人CLDN18.2的靶点特异性。
定义
除非另有定义，本文中使用的科学和技术术语的含义是本领域技术人员所通常理解的含义。本文中所述的细胞和组织培养、分子生物学以及蛋白质和寡或多核苷酸化学及杂交中使用的命名和技术是本领域公知且普遍使用的。对于重组DNA、寡核苷酸合成和组织培养与转化(如电穿孔、脂质转染)，使用了标准技术。酶促反应和纯化技术根据生产商的说明书或本领域普遍使用或本文所述的方法进行。前述技术和方法通常根据本领域公知且本说明书中引用和讨论的多部综合和较具体的文献中描述的那样使用。参见例如Sambrook等，Molecular Cloning:A Laboratory Manual)(第2版，Cold Spring Harbor LaboratoryPress，纽约冷泉港(1989))。本文所述的分析化学、合成有机化学以及医学和药学化学中使用的命名以及实验室方法和技术是本领域公知且普遍使用的。
术语“抗体”是指，是指通常由两对多肽链[每对具有一条轻(L)链和 一条重(H)链]组成的免疫球蛋白分子。从一般意义上，重链可以理解为抗体中分子量较大的多肽链，轻链是指抗体中分子量较小的多肽链。轻链可分类为κ和λ轻链。重链通常可分类为μ、δ、γ、α或ε，并且分别将抗体的同种型定义为IgM、IgD、IgG、IgA和IgE。在轻链和重链内，可变区和恒定区通过大约12或更多个氨基酸的“J”区连接，重链还包含大约3个或更多个氨基酸的“D”区。各重链由重链可变区(VH)和重链恒定区(CH)组成。重链恒定区由3个结构域(CH1、CH2和CH3)组成。各轻链由轻链可变区(VL)和轻链恒定区(CL)组成。轻链恒定区由一个结构域CL组成。抗体的恒定区可介导免疫球蛋白与宿主组织或因子，包括免疫系统的各种细胞(例如，效应细胞)和经典补体系统的第一组分(C1q)的结合。VH和VL区还可被细分为具有高变性的区域[称为互补决定区(CDR)]，其间散布有较保守的称为构架区(FR)的区域。各VH和VL由按下列顺序：FR1、CDR1、FR2、CDR2、FR3、CDR3、FR4从氨基末端至羧基末排列的3个CDR和4个FR组成。各重链/轻链对应的可变区(VH和VL)分别形成抗体结合部位。氨基酸至各区域或结构域的分配遵循Kabat EA.Et al.,Sequences of Proteins ofImmunological Interest[National Institutes of Health,Bethesda,Md.(1987and1991)]，或Chothia&Lesk 1987)].Mol.Biol.196:901-917；Chothia等人(1989)Nature342:877-883的定义。特别地，重链还可以包含3个以上CDR，例如6、9或12个。例如在本发明的双特异性抗体中，重链可以是IgG抗体的重链的N端连接另一个抗体的ScFv，这种情况下重链含有9个CDR。
术语抗体的“抗原结合片段”是指包含全长抗体的片段的多肽，其保持特异性结合全长抗体所结合的相同抗原的能力，和/或与全长抗体竞争对抗原的特异性结合，其也被称为“抗原结合部分”。通常参见Fundamental Immunology,Ch.7，Paul,W.，ed.，第2版，Raven Press，N.Y.(1989)，其以其全文通过引用合并入本文，用于所有目的。可通过重组DNA技术或通过完整抗体的酶促或化学断裂产生抗体的抗原结合片段。在一些情况下，抗原结合片段包括Fab、Fab’、F(ab’)2、Fd、Fv、dAb和互补决定区(CDR)片段、单链结合片段(例如，scFv)、嵌合抗体、双抗体(diabody)和这样的多肽，其包含足以赋予多肽特异性抗原结合能力的抗体的至少一部分。
术语“Fv”意指向抗体的单臂的VL和VH结构域组成的抗体片段； 术语“Fab”意指由VL、VH、CL和CH1(或者CH)结构域组成的抗体片段；术语“F(ab’)2”意指包含通过铰链区上的二硫桥连接的两个Fab片段的抗体片段。
在一些情况下，抗体的抗原结合片段是单链结合片段(例如，scFv)，其中VL和VH结构域通过使其能够产生为单个多肽链的连接体配对形成单价分子[参见，例如，Bird等人，Science 242:423-426(1988)和Huston等人，Proc.Natl.Acad.Sci.USA 85:5879-5883(1988)]。此类scFv分子可具有一般结构：NH2-VL-接头-VH-COOH或NH2-VH-接头-VL-COOH。合适的现有技术接头由重复的G4S氨基酸序列或其变体组成。例如，可使用具有氨基酸序列(G4S)4接头，但也可使用其变体[Holliger等人(1993)，Proc.Natl.Acad.Sci.USA 90:6444-6448]。
可使用本领域技术人员已知的常规技术(例如，重组DNA技术或酶促或化学断裂法)从给定的抗体获得抗体的抗原结合片段(例如，上述抗体片段)，并且以与用于完整抗体的方式相同的方式就特异性筛选抗体的抗原结合片段。
在本文中，除非上下文明确指出，否则当提及术语“抗体”时，其不仅包括完整抗体，而且包括抗体的抗原结合片段。
术语“分离的”或“被分离的”指的是，从天然状态下经人工手段获得的。如果自然界中出现某一种“分离”的物质或成分，那么可能是其所处的天然环境发生了改变，或从天然环境下分离出该物质，或二者情况均有发生。例如，某一活体动物体内天然存在某种未被分离的多聚核昔酸或多肽，而从这种天然状态下分离出来的高纯度的相同的多聚核昔酸或多肽即称之为分离的。术语“分离的”或“被分离的”不排除混有人工或合成的物质，也不排除存在不影响物质活性的其它不纯物质。
术语“宿主细胞”是指，可用于导入载体的细胞，其包括但不限于，如大肠杆菌等原核细胞，如酵母细胞等的真菌细胞，如S2果蝇细胞或Sf9等的昆虫细胞，或者如纤维原细胞，CHO细胞，COS细胞，NSO细胞，HeLa细胞，BHK细胞，HEK 293细胞或人细胞等的动物细胞。
术语“KD”是指特定抗体一抗原相互作用的解离平衡常数(KD)，其用于描述抗体与抗原之间的结合亲和力。平衡解离常数越小，抗体一抗原结合越紧密，抗体与抗原之间的亲和力越高。通常，抗体以小于大约10-5M， 例如小于大约10-6M、10-7M、10-8M、10-9M或10-10M或更小的解离平衡常数结合抗原，例如，如使用表面等离子体共振术(SPR)在BIACORE仪中测定的。例如用KINEXA方法KINEXA 400仪器上检测到的抗体和细胞结合的亲和力。
术语“特异性结合”指抗体与抗原的一种或多种抗原决定簇反应而不与其他多肽反应或以很低的亲和性(Kd>10 -6)结合其他多肽。抗体包括但不限于多克隆、单克隆、嵌合、dAb(结构域抗体)、单链、Fab、Fab’和F(ab’)2片段、Fv、scFv及Fab表达文库。单克隆抗体(mAb)是由单一的克隆细胞株得到的抗体，所述的细胞株不限于真核的、原核的或噬菌体的克隆细胞株。单克隆抗体或抗原结合片段可以用如杂交瘤技术、重组技术、噬菌体展示技术及合成技术如CDR grafting或其它现有技术进行重组得到。
本发明所述的“鼠源抗体”为根据本领域知识和技能制备的对人CLDN18.2的单克隆抗体。制备时用CLDN18.2抗原注射试验对象，然后分离表达具有所需序列或功能特性的抗体的杂交瘤。
本发明所述的“嵌合抗体”是将鼠源性抗体的可变区与人抗体的恒定区融合而成的抗体，可以减轻鼠源性抗体诱发的免疫应答反应。建立嵌合抗体，要先建立分泌鼠源性特异性单抗的杂交瘤，然后从小鼠杂交瘤细胞中克隆可变区基因，再根据需要克隆人抗体的恒定区基因，将小鼠可变区基因与人恒定区基因连接成嵌合基因后插入表达载体中，最后在真核工业系统或原核工业系统中表达嵌合抗体分子。
本发明所述的“人源化抗体”也称为CDR移植抗体，是将小鼠的CDR序列移植到人的抗体可变区框架(FR)中产生的抗体。此类可变区框架序列可以从公共的DNA数据库或公开的参考文献获得，例如从ImMunoGeneTics(IMGT)网站http://imgt.cines.fr得到或从免疫球蛋白杂志，2001ISBN012441351上获得。
术语CLDN18.2”包括同种型、哺乳动物(例如人)的CLDN18.2、人CLDN18.2的物种同源物和包含至少一个与CLDN18.2的共同表位的类似物。CLDN18.2(例如人CLDN18.2)的氨基酸序列是本领域中己知的，如NCBI数据库显示。
术语“CLDN18.1”包括同种型、哺乳动物(例如人)的CLDN18.1、人CLDN18.1的物种同源物和包含至少一个与CLDN18.1的共同表位的类 似物。CLDN18.1(例如人CLDN18.1)的氨基酸序列是本领域中己知的，如NCBI数据库显示。
“任选”、“任选地”、“任意”或“任一”意味着随后所描述地事件或环境可以但不必发生，该说明包括该事件或环境发生或不发生地场合。例如，“任选包含1个抗体重链可变区”意味着特定序列的抗体重链可变区可以但不必须存在。
术语“药物组合物”表示含有一种或多种本发明所述化合物或其生理学上/可药用的盐或前体药物与其他化学组分的混合物，以及其他组分例如生理学/可药用的载体和赋形剂。药物组合物的目的是促进对生物体的给药，利于活性成分的吸收进而发挥生物活性。治疗性组合物一般应当是无菌的并且在制造和储存条件下稳定。可以将组合物配制为溶液、微乳液、分散剂、脂质体或适合高抗体浓度的其他有序结构。可以通过将活性化合物(即抗体或抗体部分)以要求的量连同上文所列举的一种成分或成分组合在适宜的溶剂中并入，根据需要，随后过滤消毒，制备无菌可注射溶液剂。
本发明所述的方法、组合物、联合治疗可以与其他活性剂或治疗方式，所述的方法包括向对象以有效治疗或预防疾病(例如，癌症)的量，施用本发明所述的抗CLDN18.2抗体分子，任选地，与PD-1、PD-L1、PD-L2、LAG-3、CTLA-4、Tim-3抗体(免疫治疗)或其它肿瘤治疗抗体，Her-2、EGFR、VEGF、VEGFR抗体等，以及ADC(抗体药物偶联，如T-DM1)，双特异抗体，化疗药物等的一种或多种抑制剂的组合，还包括施用抗CLDN18.2抗体分子、额外的活性剂或全部可以按这样的量或剂量施用，所述量或剂量高于、低于或等于单独(例如，作为单一疗法)使用的每种活性剂的量或剂量。抗CLDN18.2抗体，额外的活性剂或全部的施用量或剂量比单独(例如，作为单一疗法)使用的每种活性剂的量或剂量低(例如，至少20％、至少30％、至少40％或至少50％)。
此外，本发明抗CLDN18.2抗体可以结合CLDN18.2诱导靶细胞(肿瘤细胞)凋亡，抑制肿瘤细胞生长，增加体内效应细胞对肿瘤细胞ADCC，CDC杀伤作用来达到治疗癌症患者的目的。因此，在某些实施方案中，本发明所描述的抗CLDN18.2抗体分子通过这些机理显示本发明抗体抗肿瘤效应。以及抑制肿瘤细胞生长的方法，包括将治疗有效量的本发明中所述 的抗CLDN18.2抗体分子施用于受试者。该方法适用于癌症的体内治疗。为了获得靶向特异治疗效果，抗CLDN18.2抗体分子可以与其它抗体一起施用。在将CLDN18.2抗体组合一种或多种活性剂施用时，该组合可以以任何顺序或同时施用癌症类型，特别是CLDN18.2高表达的肿瘤患者。在某些方面中，提供在对象中治疗对象(例如，减少或缓解)过度增生性病状或疾病(例如，癌症)，例如，实体瘤、血液学癌、软组织肿瘤或转移性病灶的方法。该方法包括向对象单独或与其他活性剂或治疗方式组合地施用本发明所述的一种或多种抗CLDN18.2抗体分子。
术语“癌”、“癌症”、“癌症病人”意在包括全部类型的癌性生长物或致瘤过程、转移性组织或恶性转化的细胞、组织或器官，无论组织病理学类型或侵袭力阶段是什么。例子包括但不限于实体瘤、血液学癌、软组织肿瘤和转移性病灶。实体瘤的例子包括恶性肿瘤，例如，多个器官系统的肉瘤和癌(包括腺癌和鳞状细胞癌)，如侵袭肝、肺、乳腺、淋巴、胃肠道(例如，结肠)、生殖泌尿道(例如，肾、膀肮上皮细胞)、前列腺和咽的那些。腺癌包括恶性肿瘤如大部分结肠癌、直肠癌、胃癌、肾细胞癌、肝癌、肺癌中的非小细胞癌、小肠癌和食道癌。鳞状细胞癌包括恶性肿瘤，如在肺、食道、皮肤、头部和颈部区域、口腔、肛门和子宫颈中。前述癌的转移性病灶也可以使用本发明所述的方法和组合物治疗或预防。针对CLDN18.2的抗体分子可以与免疫原性剂如癌细胞、纯化的肿瘤抗原(包括重组蛋白、肽和糖分子)、细胞和用编码免疫剌激性细胞因子的基因转染的细胞组合。
术语“抗体依赖性细胞介导的细胞毒性”(ADCC)描述了优选地需要靶细胞被抗体标记的效应细胞(特别是淋巴细胞)的细胞杀伤能力。当抗体与肿瘤细胞上的抗原结合并且抗体Fc结构域与免疫效应细胞表面上的Fc受体(FcR)接合时，优选发生ADCC。已经鉴定了数个Fc受体家族，并且特定细胞群特征性地表达限定的Fc受体。ADCC可被视为直接诱导导致抗原呈递和诱导肿瘤导向的T细胞应答的可变程度的立即肿瘤破坏的机制。优选地，ADCC的体内诱导将导致肿瘤导向的T细胞应答和宿主源性抗体应答。
术语“补体依赖性细胞毒性”(CDC)，是可由抗体指导的另一种细胞杀伤方法。IgM是补体激活最有效的同种型。IgG1和IgG3二者在通过经典补体激活途径指导CDC方面也非常有效。优选地，在该级联反应中， 抗原-抗体复合物的形成导致参与抗体分子(例如IgG分子)的CH2结构域上紧密接近的多个C1q结合位点暴露(C1q是补体C1的三种亚组分之一)。优选地，这些暴露的C1q结合位点将先前低亲和力的C1q-IgG相互作用转化为高亲合力相互作用，其触发涉及一系列其他补体蛋白的级联事件并导致效应细胞趋化/活化剂C3a和C5a的蛋白水解释放。优选地，补体级联以形成膜攻击复合物结束，所述复合物在细胞膜中产生有利于水和溶质自由进入和离开细胞的孔。
令人吃惊地发现，本文中抗CLDN18.2抗体制备的抗体-药物缀合物能够通过诱导补体依赖性细胞毒性(CDC)介导的裂解和/或抗体依赖性细胞的细胞毒性(ADCC)介导的裂解来介导杀伤细胞，特别是表达CLDN18.2的细胞，例如癌细胞。因此，在一个实施方案中，本发明的抗体-药物缀合物通过诱导补体依赖性细胞毒性(CDC)介导的裂解和/或抗体依赖性细胞的细胞毒性(ADCC)介导的裂解(优选通过诱导CDC介导的裂解和ADCC介导的裂解)来介导细胞杀伤。
附图说明
以下，结合附图来详细说明本发明的实施方案，其中：
图1显示了抗人CLDN18.2嵌合抗体的体外细胞结合实验结果。
图2显示了抗人CLDN18.2人源化抗体的补体依赖性细胞毒性(CDC)实验结果，其中2A：CHOK1；2B：BxPC3；2C：NCI-N87。
图3显示了抗人CLDN18.2人源化抗体的抗体依赖性细胞毒性(ADCC)实验结果，其中3A：CHOK1；3B：BxPC3；3C：NCI-N87。
图4显示了抗人CLDN18.2人源化抗体的同族蛋白结合特征分析结果。
图5显示了抗人CLDN18.2人源化抗体在不同浓度下与人CLDN18.1表达细胞的结合情况。
图6显示了抗人CLDN18.2人源化抗体的种属交叉结合特征分析结果。
图7显示了制备的各组CART细胞的阳性率检测结果。
图8显示了构建的各CHO细胞株的不同抗原表达情况。
图9显示了各组CART细胞与靶细胞孵育后上清中IFN-γ检测结果。
图10显示了各组CART细胞与靶细胞孵育后CD25表达的检测结果。
实施发明的最佳方式
以下参照具体的实施例来说明本发明。本领域技术人员能够理解，这些实施例仅用于说明本发明，其不以任何方式限制本发明的范围。
下述实施例中的实验方法，如无特殊说明，均为常规方法。下述实施例中所用的药材原料、试剂材料等，如无特殊说明，均为市售购买产品。其中：
IMAB362的重链和轻链序列参见SEQ ID NO:126和SEQ ID NO:127。
抗原人CLDN18.2参见NP_001002026.1，抗原人CLDN18.1参见NP_057453.1。
附图中的阴性对照Isotype control(同型对照)为抗CD33全长IgG抗体Lintuzumab。
实施例1鼠源单克隆抗体的筛选
使用细胞表面稳定表达人CLDN18.2蛋白的CHOK1细胞免疫Balb/c小鼠，1个月后用流式细胞仪术(FACS)分析小鼠血清，取血清抗体滴度高的小鼠取其脾脏，标准方法分离得到的脾细胞与骨髓瘤细胞P3X63Ag8.653使用PEG或者电融合方法进行融合。将融合后的杂交瘤细胞接种于384孔板中，培养10-14天后，取上清用FACS分析杂交瘤细胞分泌的抗体，筛选得到若干克隆，所述克隆能够结合细胞表面稳定表达人CLDN18.2蛋白的CHOK1细胞而不能够结合细胞表面稳定表达人CLDN18.1蛋白的CHOK1细胞。通过有限稀释的方法将筛选到的克隆单细胞化，3轮之后得到的每个杂交瘤细胞克隆只分泌一个抗体。
将分泌抗人CLDN18.2抗体的杂交瘤细胞扩大培养后，按照RNAfast200试剂盒(上海飞捷生物技术有限公司)说明书步骤提取细胞总RNA；利用5×PrimeScript RT Master Mix(Takara)将杂交瘤细胞总RNA反转录成cDNA；使用简并引物(Anke Krebber.1997)和Extaq PCR试剂(Takara)扩增抗体轻链可变区IgVL(κ)和重链可变区VH序列；利用PCR clean-up Gel extraction试剂盒(Macherey-Nagel公司)纯化PCR扩增产物；按照pClone007 Simple Vector Kit试剂盒(擎科生物科技有限公司)说明书将扩增PCR产物连接至 T载体并转化大肠杆菌感受态细胞，菌株扩增、抽提质粒后进行DNA测序获得单克隆抗体可变区序列。
表1.鼠源抗体的轻重链可变区
鼠源抗体 重链可变区(VH) 轻链可变区(VL)
11M23 SEQ ID NO:1 SEQ ID NO:2
16K15 SEQ ID NO:3 SEQ ID NO:4
18B21 SEQ ID NO:5 SEQ ID NO:6
20L17 SEQ ID NO:7 SEQ ID NO:8
43B5 SEQ ID NO:9 SEQ ID NO:10
43L6 SEQ ID NO:11 SEQ ID NO:12
46J05 SEQ ID NO:13 SEQ ID NO:14
48G12 SEQ ID NO:15 SEQ ID NO:16
50C14 SEQ ID NO:17 SEQ ID NO:18
52E22 SEQ ID NO:19 SEQ ID NO:20
8K13 SEQ ID NO:21 SEQ ID NO:22
>11M23_vh(SEQ ID NO:1)
Figure PCTCN2020118424-appb-000001
>11M23_vl(SEQ ID NO:2)
Figure PCTCN2020118424-appb-000002
>16K15_vh(SEQ ID NO:3)
Figure PCTCN2020118424-appb-000003
>16K15_vl(SEQ ID NO:4)
Figure PCTCN2020118424-appb-000004
>18B21_vh(SEQ ID NO:5)
Figure PCTCN2020118424-appb-000005
>18B21_vl(SEQ ID NO:6)
Figure PCTCN2020118424-appb-000006
>20L17_vh(SEQ ID NO:7)
Figure PCTCN2020118424-appb-000007
>20L17_vl(SEQ ID NO:8)
Figure PCTCN2020118424-appb-000008
>43B5_vh(SEQ ID NO:9)
Figure PCTCN2020118424-appb-000009
>43B5_vl(SEQ ID NO:10)
Figure PCTCN2020118424-appb-000010
>43L6_vh(SEQ ID NO:11)
Figure PCTCN2020118424-appb-000011
>43L6_vl(SEQ ID NO:12)
Figure PCTCN2020118424-appb-000012
>46J05_vh(SEQ ID NO:13)
Figure PCTCN2020118424-appb-000013
>46J05_vl(SEQ ID NO:14)
Figure PCTCN2020118424-appb-000014
>48G12_vh(SEQ ID NO:15)
Figure PCTCN2020118424-appb-000015
>48G12_vl(SEQ ID NO:16)
Figure PCTCN2020118424-appb-000016
>50C14_vh(SEQ ID NO:17)
Figure PCTCN2020118424-appb-000017
>50C14_vl(SEQ ID NO:18)
Figure PCTCN2020118424-appb-000018
>52E22_vh(SEQ ID NO:19)
Figure PCTCN2020118424-appb-000019
>52E22_vl(SEQ ID NO:20)
Figure PCTCN2020118424-appb-000020
>8K13_vh(SEQ ID NO:21)
Figure PCTCN2020118424-appb-000021
>8K13_vl(SEQ ID NO:22)
Figure PCTCN2020118424-appb-000022
实施例2抗人CLDN18.2嵌合抗体的制备
将鼠源抗人CLDN18.2单克隆抗体的重链可变区序列和公开发表的人单克隆抗体IgG1亚类的重链恒定区序列(参见SEQ ID NO:124)拼接在一起，构建到哺乳动物细胞表达载体中；将鼠源抗人CLDN18.2单克隆抗体的轻链可变区序列和公开发表的人单克隆抗体κ亚类的轻链恒定区序列(参见SEQ ID NO:125)拼接在一起，构建到哺乳动物细胞表达载体中。构建好的抗人CLDN18.2嵌合抗体的重链载体和轻链载体配对混合，使用聚乙烯亚胺(PEI)转染HEK293细胞，约7天后收集细胞上清，使用ProteinA纯化得到抗人CLDN18.2嵌合抗体蛋白。
本发明的嵌合抗体命名为“鼠源抗体简称-xiIgG”。
实施例3抗人CLDN18.2嵌合抗体的体外细胞结合实验
将抗人CLDN18.2嵌合抗体从100nM的起始浓度开始做2倍的梯度倍比稀释，共16个浓度点，各个浓度点的抗体取10ul加入384孔板。100g室温离心5分钟收集细胞表面表达CLDN18.2的CHOK1细胞，用含0.5％BSA的PBS洗涤细胞一次，100g室温离心5分钟，重悬细胞为密度约2x10 6个细胞/毫升，取10ul加入到已加抗体的384孔板的孔中。4℃孵育1小时后，加入荧光标记的羊抗人IgG二抗。继续于4℃孵育1小时后，用流式细胞仪分析细胞群的平均荧光读值。
结果显示嵌合抗体与表达人CLDN18.2细胞有nM级别的特异结合，见图1。
实施例4抗人CLDN18.2鼠源抗体的人源化
综合Kabat、Chothia的抗体编码方案，确定鼠源抗体的重链和轻链的6个抗原互补决定簇(CDR)的氨基酸序列区域及支撑抗体保守三维构象的框架区域(framework region)。随后通过分析搜索已知人源抗体序列，选择与鼠源抗体最为相似接近的人源抗体重链可变区序列，如IGHV1|IGHJ4*01，选择其抗体框架区序列作为模板，将鼠源抗体重链CDR与人源抗体框架区结合，最终生成人源化抗体重链可变区序列。同样过程，生成人源化抗体轻链可变区序列。
鼠源抗体CDR直接移植至人框架区的抗体常出现结合活性急剧下降， 因此需要将框架区个别氨基酸从人源的改回鼠源的。确定回复突变位点，一是对照设计好的人源化抗体序列和原始的鼠源抗体序列，检查有哪些氨基酸的不同；二是检查这些氨基酸是否对支持抗体结构起重要作用或者对与抗原的结合起重要作用。人源化设计后的序列的同时需要检查是否有一些潜在的翻译后修饰位点(PTM)，如N(天冬酰胺)糖基化位点、N脱酰胺化位点、D(天冬氨酸)异构化位点等。
将人源化抗体重链可变区基因构建到含人单克隆抗体IgG1亚类的重链恒定区基因的哺乳动物细胞表达载体中；轻链可变区基因构建到含人单克隆抗体κ亚类的轻链恒定区基因的哺乳动物细胞表达载体中。构建好的抗人CLDN18.2人源化抗体的重链载体和轻链载体配对混合，使用聚乙烯亚胺(PEI)转染HEK293细胞，约7天后收集细胞上清，使用ProteinA纯化得到抗人CLDN18.2人源化抗体蛋白。
本发明的人源化抗体命名为“鼠源抗体简称-hz”。鼠源抗体CDR直接移植至人框架区的抗体命名为“鼠源抗体简称-hz00”。进一步改造得到的抗体根据序列不同进行编号。
利用Fortebio(BLITZ pro1.1.0.28)仪器分析鼠源嵌合抗体及其人源化抗体与抗原人CLDN18.2的结合动力学参数。测定前先将NTA生物探针浸泡于PBS中10分钟；然后将该探针置于含100nM的抗原的PBS中300秒，捕获带His标签的抗原；进一步将探针与100nM抗体进行结合反应，结合时间400秒；之后将探针转移至PBS中，进行解离反应，时间为600秒。实验完毕，扣除空白对照响应值，用软件进行1：1Langmuir结合模式拟合，计算抗原抗体结合的动力学常数。结果见表2。
表2.鼠源抗体人源化后的结合动力学参数比较
Figure PCTCN2020118424-appb-000023
Figure PCTCN2020118424-appb-000024
结果显示，人源化并移除了关键的翻译后修饰位点(PTM)后，11M23-hz22相对鼠源嵌合抗体，解离常数值上升了10倍以上，因此将其从候选分子名单中去除。其余的8K13-hz24、16K15-hz22和52E22-hz12的解离常数值与原始鼠源嵌合抗体比，上升幅度在1-4倍之间，可以选做先导分子继续开展后续的研究。其中16K15-hz22轻链氨基酸序列中包含2个连续的“NN”残基，做了进一步优化的16K15-hz22_2和16K15-hz22_3突变抗体，分别将“NN”残基变为“SN”和“QN”残基。
表3.人源化抗体的轻重链可变区
Figure PCTCN2020118424-appb-000025
Figure PCTCN2020118424-appb-000026
>16K15_vl_hz2(SEQ ID NO:24)
Figure PCTCN2020118424-appb-000027
>16K15_vl_hz2_N-S(SEQ ID NO:25)
Figure PCTCN2020118424-appb-000028
>16K15_vl_hz2_N-Q(SEQ ID NO:26)
Figure PCTCN2020118424-appb-000029
>16k15_vh_hz2(SEQ ID NO:23)
Figure PCTCN2020118424-appb-000030
>52E22_vl_hz2(SEQ ID NO:28)
Figure PCTCN2020118424-appb-000031
Figure PCTCN2020118424-appb-000032
>52E22_vh_hz1(SEQ ID NO:27)
Figure PCTCN2020118424-appb-000033
>8K13_vl_hz4_N-S_N-Q(SEQ ID NO:30)
Figure PCTCN2020118424-appb-000034
>8K13_vh_hz2(SEQ ID NO:29)
Figure PCTCN2020118424-appb-000035
实施例5抗人CLDN18.2人源化抗体的体外结合亲和力的动力学实验
采用GE公司BIAcore仪器S200测定抗体抗原相互作用力。
参考GE公司Human antibody capture kit(货号BR-1008-39，Lot10261753)操作说明，首先在传感芯片CM5分析通道和对照样品通道都饱和偶联最大量抗人Fc抗体，然后在分析通道流过含有7.5μg/ml抗人CLDN18.2嵌合抗体、人源化抗体或对照抗体IMAB362的缓冲液使其均匀分布，最后在分析通道和对照样品通道一起流过梯度稀释的抗原样品(起始浓度20nM，1:3稀释8个浓度点，并且设定0.741nm浓度点重复)，测定抗体抗原结合后发生的光反应值。经仪器软件拟合分析，最终得到抗体的结合常数Kon和解离常数Koff，以及亲和力常数KD。
结果表明，抗人CLDN18.2人源化抗体的体外结合亲和力常数与原始鼠源抗体比没有显著的改变，与IMAB362相比低了1个数量级，见表4。
表4.本发明抗体的结合动力学
抗体 ka(M-1s-1) kd(s-1) KD(M)
8K13-xiIgG 8.19E+04 5.73E-04 6.99E-09
8K13-hz24 7.09E+04 2.02E-03 2.85E-08
16K15-xiIgG 1.07E+05 1.44E-03 1.35E-08
16K15-hz22 5.71E+04 5.63E-04 9.85E-09
52E22-xiIgG 4.90E+05 5.45E-04 1.11E-09
52E22-hz12 1.46E+05 1.72E-04 1.18E-09
IMAB362 1.48E+06 0.201 1.36E-07
实施例6抗人CLDN18.2人源化抗体的体外细胞学试验
6.1补体依赖性细胞毒性(CDC)
使用Quidel公司的商品化人血清全补体对本发明人源化抗体进行分析，分析其对稳定表达人CLDN18.2的CHOK1、BxPC3和NCI-N87细胞诱导补体依赖性细胞毒性(CDC)的能力。
将细胞与终浓度为250μg/ml至3.8ng/ml的待测抗体混匀；加入溶于细胞培养基RPMI-1640中的6.25％人血清全补体，在37℃下孵育3小时；然后通过CCK-8试剂盒进行细胞毒性检测；最终通过MD酶标仪检测450nm吸光度。通过吸光值采用softmax pro7软件进行4参数拟合曲线，计算样品的EC50值。
结果表明，抗人CLDN18.2人源化抗体针对靶点表达细胞有特异的补体依赖性细胞毒(CDC)活性，并且细胞杀伤活性显著优于IMAB362，见图2和表5。
表5.本发明抗体的CDC
靶点表达细胞 a.CHOK1 b.BxPC3 c.NCI-N87
抗体 EC50(nM) EC50(nM) EC50(nM)
8K13-hz24 IgG 21.27 28.53 57.7
16K15-hz22 IgG 5.2 12.22 17.36
52E22-hz12 IgG 2.08 NA NA
IMAB362 30.45 52.23 474.2
6.2抗体依赖性细胞毒性(ADCC)
使用工程改造的Jurkat细胞作为效应细胞，该细胞稳定表达FcγRIIIa-FcεRIaγ杂合受体，由NFAT应答元件驱动表达萤火虫萤光素酶。抗体在ADCC作用机制中的生物活性通过NFAT通路活化产生的萤光素酶定 量。将1.5E5个效应细胞与终浓度33μg/ml至85pg/ml的待测抗体混匀，然后将2.5E4个靶细胞加入其中(效应细胞与靶细胞E:T比例6:1)，在37℃下孵育16小时；然后通过Promega公司试剂盒Bio-Glo TM Luciferase Assay System进行检测；最终通过MD酶标仪检测LUM值。
数据处理方式如下，诱导倍数＝(受检孔读值–背景值)/(阴性对照孔读值–背景值)，用prism软件进行4参数拟合曲线，计算出样品的EC50值。
结果表明，抗人CLDN18.2人源化抗体针对靶点表达细胞有特异的抗体依赖性细胞毒(ADCC)活性，细胞杀伤活性与IMAB362相当，见图3和表6。
表6.本发明抗体的ADCC
靶点表达细胞 a.CHOK1 b.BxPC3 c.NCI-N87
抗体 EC50(nM) EC50(nM) EC50(nM)
8K13-hz24 IgG 0.5894 0.3045 0.1499
16K15-hz22 IgG 0.7122 0.1759 0.0677
52E22-hz12 IgG 0.5672 NA NA
IMAB362 0.5929 0.1056 0.0909
实施例7抗人CLDN18.2人源化抗体的同簇蛋白结合特征分析
将人CLDN18.2和CLDN18.1的基因分别构建到真核表达载体中，使用聚乙烯亚胺(PEI)转染HEK293细胞。转染后第三天离心收集细胞，用PBS洗涤细胞1次，重悬细胞密度为2×10 6/ml，每个384孔板中加入10ul的细胞；第二步往384孔板中加入不同浓度的人源化抗体，4℃孵育1小时；第三步加入荧光标记的羊抗人IgG二抗，4℃孵育1小时；使用流式细胞仪读取384孔板的荧光值。分析数据获得细胞与抗人CLDN18.2人源化抗体的结合特征。实验用的阳性对照为商品化抗人CLDN18兔单抗34H14L15(购自Abcam公司)，阴性Isotype control(同型对照)为抗CD33全长IgG抗体Lintuzumab。
结果表明，抗人CLDN18.2人源化抗体表现出结合人CLDN18.2而不结合人CLDN18.1的特征，见图4；并且，在低、中、高三种浓度下与人CLDN18.1细胞的非特异结合均比IMAB362低，见图5。
实施例8抗人CLDN18.2人源化抗体的人、猴、鼠种属交叉结合特征 分析
将人、鼠和恒河猴(Rhesus)的CLDN18.2基因分别构建到真核表达载体中，使用聚乙烯亚胺(PEI)转染HEK293细胞，2天后收集细胞。使用流式细胞仪术分析细胞与抗人CLDN18.2人源化抗体的结合特异性。流式细胞实验方法参见实施例7。
结果表明，抗人CLDN18.2人源化抗体16K15-22 IgG和三个种属的CLDN18.2均有结合，8K13-24 IgG和52E22-12 IgG与猴子的CLDN18.2结合但不与小鼠的CLDN18.2结合。结果见图6。
实施例9采用抗人CLDN18.2人源化抗体的CART细胞制备及其活化9.1慢病毒包装
按照表7分组情况，进行慢病毒包装。首先构建了包含不同抗体基因的慢病毒载体质粒pLTR，测序正确以后使用Qiagen公司的质粒抽提试剂盒提取它们的质粒DNA，质粒DNA溶于除菌的TE中，以紫外光吸收法测定其浓度及纯度，保证所提质粒DNA的A260/A280在1.8～2.0之间。同时提取两种辅助包装元件载体质粒pCMV-VSV-G和pCMV-dR8.2的DNA。准备转染用的HEK293T细胞，需新鲜传代，生长至约60％的汇合度。使用磷酸钙作为转染试剂将3种质粒共转入HEK293T细胞。转染48小时后，低温离心收集含包装好病毒的细胞上清，使用0.45μm的过滤器去除细胞碎片。使用超滤离心管对病毒进行浓缩换液，分装后保存在-80℃冰箱。取少量病毒浓缩液用FACS法测定病毒滴度。
表7.慢病毒分组
编号 病毒 病毒滴度 组别
135 LV-135.N 8.75E+06 阴性对照
417 LV-417.N 1.65E+07 16k15(16K15-hz22)scfv*
418 LV-418.N 1.38E+07 52E22(52E22-hz12)scfv*
419 LV-419.N 5.13E+07 8K13(8K13-hz24)scfv*
420 LV-420.N 1.50E+07 阳性对照
表7中阴性对照是不结合CLDN18.2的其他抗体，阳性对照是科济生物hu8E5抗体(参见WO2018006882A1)。*所示单链抗体为相应的人源化VH、VL通过短肽(GSTSGGGSGGGSGGGGSS)连接形成。
9.2 CART细胞制备
选择HBV、HCV和HIV检测阴性的健康供者，肘正中静脉抽血100ml，Ficoll密度梯度离心分离PBMC白膜层，按DynaBeads CD3/CD28(Lifetechnologies，货号：40203D)与CD3+T细胞比例3:1，分离CD3+T细胞，活化24小时后流式检测CD25+CD69+T细胞比例。CD3+T活化后，进行慢病毒转导，MOI为5。用Novonectin包被24孔板37℃孵育2小时，将上述操作后得到的细胞悬液分别与制备得到的各种慢病毒(MOI＝5)、
Figure PCTCN2020118424-appb-000036
F108(Sigma，货号：07579-250G-F)、Tscm(2U/ml)配制成转导体系置于包被的24孔板中，细胞密度调整至1.0E+06/ml，500g离心30min，离心后37℃ CO 2培养箱静置培养48h。转染后以含5％FBS X-vivo15培养液(LONZA，货号：04-418Q)培养，隔日补充Tscm(终浓度2U/ml)，计数细胞，调整细胞密度至0.5E+06/ml，培养至第8-10天收获细胞。
得到的各组CART细胞的阳性率检测结果见图7。
9.3 CART细胞活化
用CHO构建表达人CLDN18.1抗原和人CLDN18.2抗原的细胞，作为靶细胞。
细胞的相关抗原表达检测结果见图8。CHO-BLANK(空白对照)、CHO-CLDN18.1无CLDN18.2抗原的表达，CHO-CLDN18.2高表达CLDN18.2抗原。
于1.5mL的离心管中将上述调整好密度的效应细胞，包括各组CAR-T细胞和未转导慢病毒T细胞，分别与靶细胞混合，效靶比16:1，用T细胞培养液X-vivo15培养液(不含自体血清以及Tscm)将总体积补足至200μL；将配制的200μL体系分别移入96孔V型板中共孵育24小时。
孵育结束后，取各组培养体系的上清检测人IFNγ。发现417组CART与CHO-CLDN18.1以及CHO-CLDN18.2孵育后，IFNγ释放显著增加，418、419、420组CART仅与CHO-CLDN18.2孵育后，IFNγ释放增加。结果见表8和图9。
表8.培养体系的上清中检测到的人IFNγ
组别 T:CHO-BLANK T:CHO-claduin18.1 T:CHO-claduin18.2
nc 1020.1 912 1095.2
135 1441.2 1458.6 1877
417 9016 60328.2 79178.6
418 3940.8 4540 78903.4
419 4486.2 4670.6 75516.8
420 7381.1 6973.2 78247
取各组CART细胞检测T细胞活化标志蛋白CD3/CD25。发现417CART与CHO-CLDN18.1以及CHO-CLDN18.2孵育后，CD25表达上调，418、419、420CART仅与CHO-CLDN18.2孵育后，CD25表达上调。见图10。
以上对本发明具体实施方式的描述并不限制本发明，本领域技术人员可以根据本发明作出各种改变或变形，只要不脱离本发明的精神，均应属于本发明所附权利要求的范围。

Claims (24)

  1. 一种抗人Claudin18.2抗体的制备方法，其特征在于，包括：
    (1)利用表面表达人Claudin18.2蛋白的细胞作为免疫原免疫动物；
    (2)利用步骤(1)中经过免疫的动物制备能产生抗体的细胞克隆；
    (3)利用表面表达人Claudin18.2蛋白的细胞作为正向筛选抗原，筛选对其具有结合活性的抗体及其产生细胞；
    (4)利用表面表达人Claudin18.1蛋白的细胞作为反向筛选抗原，排除对其具有结合活性的抗体及其产生细胞。
  2. 根据权利要求1所述的制备方法，其特征在于，所述步骤(1)中表达人Claudin18.2蛋白的细胞源自与所述被免疫动物相同的物种，优选所述表达人Claudin18.2蛋白的细胞为小鼠细胞、所述被免疫动物为小鼠。
  3. 根据权利要求1所述的制备方法，其特征在于，所述步骤(2)中选自以下技术制备能产生抗体的细胞克隆：杂交瘤技术、单细胞扩增技术。
  4. 根据权利要求1所述的制备方法，其特征在于，所述步骤(3)中的正向筛选抗原与步骤(1)中的免疫原相同；所述步骤(4)中的反向筛选抗原与步骤(1)中免疫原的区别仅在于所述表达的蛋白为人Claudin18.1。
  5. 根据权利要求1所述的制备方法，其特征在于，所述步骤(3)、(4)采用选自以下的方法进行筛选：酶联免疫法(ELISA)、荧光共振能量转移(FRET)。
  6. 根据权利要求1至6中任一项所述的制备方法获得的抗人Claudin18.2抗体。
  7. 根据权利要求6所述的抗人Claudin18.2抗体，其特异性结合人Claudin18.2的N端，优选特异性结合人Claudin18.2 N端的胞外区，包括第一胞外环(Extracellular Loop 1，ECL1)。
  8. 根据权利要求6所述的抗人Claudin18.2抗体，其对人CLDN18.2有nM级的特异性结合；并且，其对人CLDN18.1的结合与同种型阴性抗体(或无关抗体)相比无显著差异。
  9. 一种抗体或其片段，所述抗体或其片段包含重链可变区(VH)和轻链可变区(VL)，其中所述重链可变区(VH)和轻链可变区(VL)包含选自以下的CDR组合(VH-CDR1、VH-CDR2、VH-CDR3；VL-CDR1、VL-CDR2、 VL-CDR3)：
    (1)如SEQ ID NO:31所示的VH-CDR1、如SEQ ID NO:32所示的VH-CDR2、如SEQ ID NO:33所示的VH-CDR3；如SEQ ID NO:34所示的VL-CDR1、如SEQ ID NO:35所示的VL-CDR2、如SEQ ID NO:36所示的VL-CDR3；
    (2)如SEQ ID NO:37所示的VH-CDR1、如SEQ ID NO:38所示的VH-CDR2、如SEQ ID NO:39所示的VH-CDR3；如SEQ ID NO:40所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:42所示的VL-CDR3；
    (3)如SEQ ID NO:43所示的VH-CDR1、如SEQ ID NO:44所示的VH-CDR2、如SEQ ID NO:45所示的VH-CDR3；如SEQ ID NO:46所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:47所示的VL-CDR3；
    (4)如SEQ ID NO:48所示的VH-CDR1、如SEQ ID NO:49所示的VH-CDR2、如SEQ ID NO:50所示的VH-CDR3；如SEQ ID NO:40所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:51所示的VL-CDR3；
    (5)如SEQ ID NO:52所示的VH-CDR1、如SEQ ID NO:53所示的VH-CDR2、如SEQ ID NO:54所示的VH-CDR3；如SEQ ID NO:55所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:56所示的VL-CDR3；
    (6)如SEQ ID NO:57所示的VH-CDR1、如SEQ ID NO:58所示的VH-CDR2、如SEQ ID NO:33所示的VH-CDR3；如SEQ ID NO:34所示的VL-CDR1、如SEQ ID NO:59所示的VL-CDR2、如SEQ ID NO:60所示的VL-CDR3；
    (7)如SEQ ID NO:61所示的VH-CDR1、如SEQ ID NO:62所示的VH-CDR2、如SEQ ID NO:63所示的VH-CDR3；如SEQ ID NO:46所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:64所示的VL-CDR3；
    (8)如SEQ ID NO:65所示的VH-CDR1、如SEQ ID NO:66所示的VH-CDR2、如SEQ ID NO:67所示的VH-CDR3；如SEQ ID NO:68所示的 VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:69所示的VL-CDR3；
    (9)如SEQ ID NO:65所示的VH-CDR1、如SEQ ID NO:70所示的VH-CDR2、如SEQ ID NO:71所示的VH-CDR3；如SEQ ID NO:72所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:73所示的VL-CDR3；
    (10)如SEQ ID NO:74所示的VH-CDR1、如SEQ ID NO:75所示的VH-CDR2、如SEQ ID NO:76所示的VH-CDR3；如SEQ ID NO:77所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:78所示的VL-CDR3；
    (11)如SEQ ID NO:79所示的VH-CDR1、如SEQ ID NO:80所示的VH-CDR2、如SEQ ID NO:81所示的VH-CDR3；如SEQ ID NO:82所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:83所示的VL-CDR3；
    (12)如SEQ ID NO:37所示的VH-CDR1、如SEQ ID NO:38所示的VH-CDR2、如SEQ ID NO:39所示的VH-CDR3；如SEQ ID NO:85所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:42所示的VL-CDR3；
    (13)如SEQ ID NO:37所示的VH-CDR1、如SEQ ID NO:38所示的VH-CDR2、如SEQ ID NO:39所示的VH-CDR3；如SEQ ID NO:85所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:86所示的VL-CDR3；
    (14)如SEQ ID NO:37所示的VH-CDR1、如SEQ ID NO:38所示的VH-CDR2、如SEQ ID NO:39所示的VH-CDR3；如SEQ ID NO:85所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:87所示的VL-CDR3；
    (15)如SEQ ID NO:74所示的VH-CDR1、如SEQ ID NO:75所示的VH-CDR2、如SEQ ID NO:76所示的VH-CDR3；如SEQ ID NO:89所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:90所示的VL-CDR3；和
    (16)如SEQ ID NO:79所示的VH-CDR1、如SEQ ID NO:91所示的 VH-CDR2、如SEQ ID NO:81所示的VH-CDR3；如SEQ ID NO:92所示的VL-CDR1、如SEQ ID NO:41所示的VL-CDR2、如SEQ ID NO:93所示的VL-CDR3。
  10. 根据权利要求6至9中任一项所述的抗体或其片段，其特征在于，所述重链可变区包含：
    SEQ ID NO:1、SEQ ID NO:3、SEQ ID NO:5、SEQ ID NO:7、SEQ ID NO:9、SEQ ID NO:11、SEQ ID NO:13、SEQ ID NO:15、SEQ ID NO:17、SEQ ID NO:19、SEQ ID NO:21、SEQ ID NO:23、SEQ ID NO:27和SEQ ID NO:29中任一个所示的氨基酸序列或与所示的氨基酸序列具有至少75％同一性的氨基酸序列；和/或
    所述轻链可变区包含：
    SEQ ID NO:2、SEQ ID NO:4、SEQ ID NO:6、SEQ ID NO:8、SEQ ID NO:10、SEQ ID NO:12、SEQ ID NO:14、SEQ ID NO:16、SEQ ID NO:18、SEQ ID NO:20、SEQ ID NO:22、SEQ ID NO:24、SEQ ID NO:25、SEQ ID NO:26、SEQ ID NO:28和SEQ ID NO:30中任一个所示的氨基酸序列或与所示的氨基酸序列具有至少75％同一性的氨基酸序列。
  11. 根据权利要求6至10中任一项所述的抗体或其片段，其特征在于，所述抗体或其片段包含的重链可变区和轻链可变区选自以下组合：
    (1)如SEQ ID NO:1所示的氨基酸序列或与如SEQ ID NO:1所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:2所示的氨基酸序列或与如SEQ ID NO:2所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (2)如SEQ ID NO:3所示的氨基酸序列或与如SEQ ID NO:3所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:4所示的氨基酸序列或与如SEQ ID NO:4所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (3)如SEQ ID NO:5所示的氨基酸序列或与如SEQ ID NO:5所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:6所示的氨基酸序列或与如SEQ ID NO:6所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (4)如SEQ ID NO:7所示的氨基酸序列或与如SEQ ID NO:7所示的氨 基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:8所示的氨基酸序列或与如SEQ ID NO:8所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (5)如SEQ ID NO:9所示的氨基酸序列或与如SEQ ID NO:9所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:10所示的氨基酸序列或与如SEQ ID NO:10所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (6)如SEQ ID NO:11所示的氨基酸序列或与如SEQ ID NO:11所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:12所示的氨基酸序列或与如SEQ ID NO:12所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (7)如SEQ ID NO:13所示的氨基酸序列或与如SEQ ID NO:13所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:14所示的氨基酸序列或与如SEQ ID NO:14所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (8)如SEQ ID NO:15所示的氨基酸序列或与如SEQ ID NO:15所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:16所示的氨基酸序列或与如SEQ ID NO:16所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (9)如SEQ ID NO:17所示的氨基酸序列或与如SEQ ID NO:17所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:18所示的氨基酸序列或与如SEQ ID NO:18所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (10)如SEQ ID NO:19所示的氨基酸序列或与如SEQ ID NO:19所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:20所示的氨基酸序列或与如SEQ ID NO:20所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (11)如SEQ ID NO:21所示的氨基酸序列或与如SEQ ID NO:21所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:22所示的氨基酸序列或与如SEQ ID NO:22所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (12)如SEQ ID NO:23所示的氨基酸序列或与如SEQ ID NO:23所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:24所示的氨基酸序列或与如SEQ ID NO:24所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (13)如SEQ ID NO:23所示的氨基酸序列或与如SEQ ID NO:23所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:25所示的氨基酸序列或与如SEQ ID NO:25所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (14)如SEQ ID NO:23所示的氨基酸序列或与如SEQ ID NO:23所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:26所示的氨基酸序列或与如SEQ ID NO:26所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (15)如SEQ ID NO:27所示的氨基酸序列或与如SEQ ID NO:27所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:28所示的氨基酸序列或与如SEQ ID NO:28所示的氨基酸序列具有至少75％同一性的氨基酸序列；
    (16)如SEQ ID NO:29所示的氨基酸序列或与如SEQ ID NO:29所示的氨基酸序列具有至少75％同一性的氨基酸序列；和，如SEQ ID NO:30所示的氨基酸序列或与如SEQ ID NO:30所示的氨基酸序列具有至少75％同一性的氨基酸序列。
  12. 根据权利要求6至11中任一项所述的抗体或其片段，其特征在于，所述抗体或其片段为单克隆抗体、单链抗体、双功能抗体、单域抗体、纳米抗体、完全或部分人源化的抗体或者嵌合抗体等任意形式，或者，所述抗体或其片段为半抗体或半抗体的抗原结合片段，例如scFv、BsFv、dsFv、(dsFv) 2、Fab、Fab'、F(ab') 2或Fv；
    优选地，所述抗体或其片段还包含人或鼠的恒定区，优选包含人或鼠的轻链恒定区(CL)和/或重链恒定区(CH)；
    更优选地，所述抗体或其片段包含选自IgG、IgA、IgM、IgD或IgE的重链恒定区和/或κ或λ型轻链恒定区。
  13. 根据权利要求6至12中任一项所述的抗体或其片段，其特征在于，所述抗体为单克隆抗体，优选为鼠源、嵌合或人源化的单克隆抗体；优选地， 所述单克隆抗体的重链恒定区为IgG1或IgG4亚型，轻链恒定区为κ型；
    优选地，所述单克隆抗体的重链恒定区包含如SEQ ID NO:124所示的氨基酸序列或者与所述氨基酸序列具有至少75％同一性的氨基酸序列；
    优选地，所述单克隆抗体的轻链恒定区包含如SEQ ID NO:125所示氨基酸序列或者与所述氨基酸序列具有至少75％同一性的氨基酸序列。
  14. 一种核酸分子，其编码权利要求6至13中任一项所述的抗体或其片段或者编码所述抗体或其片段中包含的重链CDR、轻链CDR、轻链可变区、重链可变区、重链或轻链。
  15. 一种载体，其包含权利要求14所述的核酸分子。
  16. 一种宿主细胞，所述宿主细胞包含权利要求14所述的核酸分子和/或权利要求15所述的载体，或者所述宿主细胞被权利要求14所述的核酸分子和/或权利要求15所述的载体转化或转染。
  17. 一种缀合物或融合蛋白，所述缀合物或融合蛋白包含权利要求6至13中任一项所述的抗体或其片段。
  18. 一种药物组合物，其包含权利要求6至13中任一项所述的抗体或其片段、权利要求14所述的核酸分子、权利要求15所述的载体、权利要求16所述的宿主细胞和/或权利要求17所述的缀合物或融合蛋白，以及可选地药学上可接受的辅料。
  19. 一种试剂盒，所述试剂盒包括权利要求6至13中任一项所述的抗体分子或其片段、权利要求14所述的核酸分子、权利要求15所述的载体、权利要求16所述的宿主细胞、权利要求17所述的缀合物或融合蛋白和/或权利要求18所述的药物组合物。
  20. 权利要求6至13中任一项所述的抗体或其片段、权利要求14所述的核酸分子、权利要求15所述的载体、权利要求16所述的宿主细胞、权利要求17所述的药物组合物或权利要求18所述的缀合物或融合蛋白在制备用于预防和/或治疗癌症的药物中的用途。
  21. 权利要求6至13中任一项所述的抗体或其片段、权利要求14所述的核酸分子、权利要求15所述的载体、权利要求16所述的宿主细胞、权利要求17所述的药物组合物或权利要求18所述的缀合物或融合蛋白在制备用于诊断癌症的试剂中的用途。
  22. 权利要求6至13中任一项所述的抗体或其片段、权利要求14所述 的核酸分子、权利要求15所述的载体、权利要求16所述的宿主细胞、权利要求17所述的药物组合物或权利要求18所述的缀合物或融合蛋白在制备CART细胞中的用途。
  23. 一种预防和/或治疗癌症的方法，所述方法包括给有此需要的受试者施用权利要求6至13中任一项所述的抗体或其片段、权利要求14所述的核酸分子、权利要求15所述的载体、权利要求16所述的宿主细胞、权利要求17所述的药物组合物或权利要求18所述的缀合物或融合蛋白，以及任选的其他药物或手段。
  24. 一种诊断癌症的方法，所述方法包括使权利要求6至13中任一项所述的抗体或其片段、权利要求14所述的核酸分子、权利要求15所述的载体、权利要求16所述的宿主细胞、权利要求17所述的药物组合物或权利要求18所述的缀合物或融合蛋白与来自受试者的样品相接触。
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