Antibody for anti-claudin 18a2 and use thereof

Abstract

Provided in the present invention is an antibody for anti-claudin 18A2 and an immune effector cell targeting claudin 18A2. Also provided are methods for inducing cell death and treating tumours.

1 . An antibody or antigen binding unit thereof that specifically binds to claudin 18A2, wherein the antibody or antigen binding unit comprises a variable heavy chain comprising at least one CDR comprising an amino acid sequence selected from the group consisting of SEQ ID NO:31, 32, 33, 37, 38, 39, 43, 44, 45, 49, 50, 51, 83, 84, 85, and an amino acid sequence which is at least 80% identical thereto and/or a variable light chain comprising at least one CDR comprising an amino acid sequence selected from the group consisting of SEQ ID NO:34, 35, 36, 40, 41, 42, 46, 47, 48, 52, 53, 54, and an amino acid sequence which is at least 80% identical thereto. 
     
     
         2 . The antibody or antigen binding unit of  claim 1 , wherein
 (a) the antibody or antigen binding unit does not significantly bind to a claudin 18A1 peptide, or   (b) the antibody or antigen binding unit exhibits less non-specific binding to a claudin 18A1 peptide when compared with a reference antigen binding unit.   
     
     
         3 . The antibody or antigen binding unit of  claim 2 , wherein,
 (a) HCDR1, HCDR2 and HCDR3 comprise the amino acid sequences of, respectively:
 i) SEQ ID NO:31, SEQ ID NO:32, and SEQ ID NO:33; 
 ii) SEQ ID NO:37, SEQ ID NO:38, and SEQ ID NO:39; 
 iii) SEQ ID NO:43, SEQ ID NO:44, and SEQ ID NO:45; 
 iv) SEQ ID NO:49, SEQ ID NO:50, and SEQ ID NO:51; 
 v) SEQ ID NO:31, SEQ ID NO:83, and SEQ ID NO:33; 
 vi) SEQ ID NO:31, SEQ ID NO:84, SEQ ID NO:33; or 
 vii) SEQ ID NO:49, SEQ ID NO:85, SEQ ID NO:51, and/or 
   (b) LCDR1, LCDR2 and LCDR3 comprise the amino acid sequences of, respectively:
 i) SEQ ID NO:34, SEQ ID NO:35, and SEQ ID NO:36; 
 ii) SEQ ID NO:40, SEQ ID NO:41, and SEQ ID NO:42; 
 iii) SEQ ID NO:46, SEQ ID NO:47, and SEQ ID NO:48; or 
 iv) SEQ ID NO:52, SEQ ID NO:53, and SEQ ID NO:54. 
   
     
     
         4 . The antibody or antigen binding unit of  claim 1 , comprising a heavy chain variable region (VH) and a light chain variable region (VL), wherein VH comprises an amino acid sequence of SEQ ID NO:3, SEQ ID NO:7, SEQ ID NO:11, SEQ ID NO:15, SEQ ID NO:17, SEQ ID NO:19, SEQ ID NO:23, SEQ ID NO:27 or SEQ ID NO:29; and has VL comprises an amino acid sequence of SEQ ID NO:1, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO:13, SEQ ID NO:21 or SEQ ID NO:25. 
     
     
         5 . The antibody or antigen binding unit of  claim 4 , wherein:
 (a) VH comprises an amino acid sequence of SEQ ID NO:3 and VL comprises an amino acid sequence of SEQ ID NO:1;   (b) VH comprises an amino acid sequence of SEQ ID NO:7 and VL comprises an amino acid sequence of SEQ ID NO:5;   (c) VH comprises an amino acid sequence of SEQ ID NO:11 and VL comprises an amino acid sequence of SEQ ID NO:9;   (d) VH comprises an amino acid sequence of SEQ ID NO:15 and VL comprises an amino acid sequence of SEQ ID NO:13;   (e) VH comprises an amino acid sequence of SEQ ID NO:17 and VL comprises an amino acid sequence of SEQ ID NO:1;   (f) VH comprises an amino acid sequence of SEQ ID NO:19 and VL comprises an amino acid sequence of SEQ ID NO:1;   (g) VH comprises an amino acid sequence of SEQ ID NO:23 and VL comprises an amino acid sequence of SEQ ID NO:21;   (h) VH comprises an amino acid sequence of SEQ ID NO:27 and VL comprises an amino acid sequence of SEQ ID NO:25; or   (i) VH comprises an amino acid sequence of SEQ ID NO:29 and VL comprises an amino acid sequence of SEQ ID NO:25.   
     
     
         6 . The antibody of  claim 1 , having
 (a) a heavy chain comprising an amino acid sequence of SEQ ID NO:63 and a light chain comprising an amino acid sequence of SEQ ID NO:65;   (b) a heavy chain comprising an amino acid sequence of SEQ ID NO:59 and a light chain comprising an amino acid sequence of SEQ ID NO:61; or   (c) a heavy chain comprising an amino acid sequence of SEQ ID NO:67 and a light chain comprising an amino acid sequence of SEQ ID NO:65.   
     
     
         7 - 9 . (canceled) 
     
     
         10 . A nucleic acid encoding the antibody or antigen binding fragment of  claim 1 . 
     
     
         11 . An expression vector comprising the nucleic acid of  claim 10 . 
     
     
         12 . A host cell comprising the expression vector of  claim 11 . 
     
     
         13 . A method for preparing an anti-claudin 18A2 targeting drug, an anti-claudin 18A2 antibody-drug conjugate, a multifunctional anti-claudin 18A2 antibody, a reagent for diagnosing a tumor expressing claudin 18A2, or an anti-claudin 18A2 chimeric antigen receptor modified immune cell, wherein the method comprises providing the antibody or antigen binding unit of  claim 1  and incorporating said antibody or antigen binding unit into the claudin 18A2 targeting drug, the anti-claudin 18A2 antibody-drug conjugate, the multifunctional anti-claudin 18A2 antibody, the reagent for diagnosing a tumor expressing claudin 18A2, or the anti claudin 18A2 chimeric antigen receptor modified immune cell. 
     
     
         14 . (canceled) 
     
     
         15 . A chimeric antigen receptor comprising the following sequentially linked components: the antibody or antigen binding unit of  claim 1 , a transmembrane region and an intracellular signal region. 
     
     
         16 . The chimeric antigen receptor of  claim 15 , wherein the intracellular signal region is selected from: an intracellular signal region sequence of CD3ζ, FcεRIγ, CD27, CD28, CD137, CD134, MyD88, CD40, or a combination thereof; and/or the transmembrane region comprises a transmembrane region of CD8 or CD28. 
     
     
         17 . (canceled) 
     
     
         18 . A nucleic acid encoding the chimeric antigen receptor  claim 16 . 
     
     
         19 . An expression vector comprising the nucleic acid of  claim 18 . 
     
     
         20 . A virus comprising the vector of  claim 19 . 
     
     
         21 - 25 . (canceled) 
     
     
         26 . A multifunctional immunoconjugate comprising:
 an antibody or antigen binding unit of  claim 1 ; and   a functional molecule linked thereto, wherein the functional molecule is selected from the group consisting of: a molecule targeting a surface marker on a tumor, a tumor-inhibiting molecule, a molecule targeting a surface marker of an immune cell, and a detectable label.   
     
     
         27 . The multifunctional immunoconjugate of  claim 26 , wherein the molecule targeting a surface marker of an immune cell is an antibody binding to a T cell surface marker, which forms a bifunctional antibody in which T cell is involved. 
     
     
         28 . A nucleic acid encoding the multifunctional immunoconjugate of claim  25 . 
     
     
         29 - 30 . (canceled) 
     
     
         31 . A kit comprising:
 a container, and the antibody or antigen binding unit of  claim 1 .   
     
     
         32 - 74 . (canceled) 
     
     
         75 . A method for inducing the death of a cell comprising a claudin 18A2 peptide, comprising contacting the cell with the antibody or antigen binding unit of  claim 1 . 
     
     
         76 - 80 . (canceled) 
     
     
         81 . A method for treating a tumor in an individual in need thereof, comprising administering to the individual an effective amount of the antibody or antigen binding unit of  claim 1 . 
     
     
         82 . The method of  claim 81 , wherein the tumor is a solid tumor. 
     
     
         83 . The method of  claim 81 , wherein the tumor is gastric cancer, esophageal cancer, intestinal cancer, pancreatic cancer, nephroblastoma, lung cancer, ovarian cancer, colon cancer, rectal cancer, liver cancer, head and neck cancer, chronic myelogenous leukemia or gallbladder cancer. 
     
     
         84 . The method of  claim 81 , further comprising administering to the individual an additional therapeutic agent. 
     
     
         85 . The method of  claim 84 , wherein the additional therapeutic agent is at least one selected from the group consisting of epirubicin, oxaliplatin and 5-fluorouracil. 
     
     
         86 . The antibody or antigen binding unit of  claim 2 , wherein the claudin 18A2 peptide comprises an amino acid sequence of SEQ ID NO:55 and/or the claudin 18A1 peptide comprises an amino acid sequence of SEQ ID NO:57. 
     
     
         87 . The antibody or antigen binding unit of  claim 1 , comprising
 (a) a heavy chain variable region comprising three CDRs, namely HCDR1, HCDR2, and HCDR3, wherein HCDR1 comprises an amino acid sequence selected from SEQ ID NO:31, SEQ ID NO:37, SEQ ID NO:43, SEQ ID NO:49, or an amino acid sequence which is at least 80% identical thereto; HCDR2 comprises an amino acid sequence selected from SEQ ID NO:32, SEQ ID NO:38, SEQ ID NO:44, SEQ ID NO:50, SEQ ID NO:83, SEQ ID NO:84, SEQ ID NO:85, or an amino acid sequence which is at least 80% identical thereto; and HCDR3 comprises an amino acid sequence selected from SEQ ID NO:33, SEQ ID NO:39, SEQ ID NO:45, SEQ ID NO:51, or an amino acid sequence which is at least 80% identical thereto; and/or   (b) a light chain variable region comprising three CDRs, namely LCDR1, LCDR2, and LCDR3, wherein LCDR1 comprises an amino acid sequence selected from SEQ ID NO:34, SEQ ID NO:40, SEQ ID NO:46, SEQ ID NO:52, or an amino acid sequence which is at least 80% identical thereto; LCDR2 comprises an amino acid sequence selected from SEQ ID NO:35, SEQ ID NO:41, SEQ ID NO:47, SEQ ID NO:53, or an amino acid sequence which is at least 80% identical thereto; and LCDR3 comprises an amino acid sequence selected from SEQ ID NO:36, SEQ ID NO:42, SEQ ID NO:48, SEQ ID NO:54, or an amino acid sequence which is at least 80% identical thereto.   
     
     
         88 . The antibody or antigen binding unit of  claim 87 , wherein,
 (a) HCDR1 is SEQ ID NO:31, HCDR2 is SEQ ID NO:32, HCDR3 is SEQ ID NO:33, LCDR1 is SEQ ID NO: 34, LCDR2 is SEQ ID NO: 35, and LCDR3 is SEQ ID NO: 36;   (b) HCDR1 is SEQ ID NO:37, HCDR2 is SEQ ID NO:38, HCDR3 is SEQ ID NO:39, LCDR1 is SEQ ID NO: 40, LCDR2 is SEQ ID NO: 41, and LCDR3 is SEQ ID NO:42;   (c) HCDR1 is SEQ ID NO:43, HCDR2 is SEQ ID NO:44, HCDR3 is SEQ ID NO:45, LCDR1 is SEQ ID NO:46, LCDR2 is SEQ ID NO:47, and LCDR3 is SEQ ID NO:48;   (d) HCDR1 is SEQ ID NO:49, HCDR2 is SEQ ID NO:50, HCDR3 is SEQ ID NO:51, LCDR1 is SEQ ID NO:52, LCDR2 is SEQ ID NO:53, and LCDR3 is SEQ ID NO:54;   (e) HCDR1 is SEQ ID NO:31, HCDR2 is SEQ ID NO:83, HCDR3 is SEQ ID NO:33, LCDR1 is SEQ ID NO:34, LCDR2 is SEQ ID NO:35, and LCDR3 is SEQ ID NO:36;   (f) HCDR1 is SEQ ID NO:31, HCDR2 is SEQ ID NO:84, HCDR3 is SEQ ID NO:33, LCDR1 is SEQ ID NO:34, LCDR2 is SEQ ID NO:35, and LCDR3 is SEQ ID NO: 36; or   (g) HCDR1 is SEQ ID NO:49, HCDR2 is SEQ ID NO:85, HCDR3 is SEQ ID NO:51, LCDR1 is SEQ ID NO:52, LCDR2 is SEQ ID NO:53, and LCDR3 is SEQ ID NO: 54.   
     
     
         89 . The antibody or antigen binding unit of  claim 1 , which is a humanized antibody, a chimeric antibody, a fully human antibody, a monoclonal antibody, a single chain antibody, a domain antibody, a multivalent antibody, a chimeric antigen receptor, an scFv, an Fv, a Fab, or a (Fab)2. 
     
     
         90 . A pharmaceutical composition comprising the antibody or antigen binding unit of  claim 1 , and a pharmaceutically acceptable carrier. 
     
     
         91 . A method for producing an antibody or antigen binding unit that specifically binds to claudin 18A2, comprising culturing the host cell of  claim 12  under suitable conditions, and obtaining the product expressed by the host cell. 
     
     
         92 . A chimeric antigen receptor-modified immune cell having the chimeric antigen receptor of  claim 15 . 
     
     
         93 . The chimeric antigen receptor-modified immune cell of  claim 92 , wherein the immune cell is selected from a T lymphocyte, NK cell, or NKT lymphocyte. 
     
     
         94 . The immune cell of  claim 93 , further comprising:
 (a) an encoding sequence for an exogenous cytokine;   (b) another expressed chimeric antigen receptor which does not contain CD3ζ but contains an intracellular signal domain of CD28, an intracellular signal domain of CD137, or a combination of the both;   (c) an expressed chemokine receptor; or   (d) an expressed siRNA which can reduce expression of PD-1;   (e) an expressed protein which can block PD-L1;   (f) a knock-out of endogenous PD-1 in the immune cell by gene editing techniques; or   (g) an expressed safety switch.   
     
     
         95 . The composition of  claim 90 , further comprising a Type I interferon.