Bispecific antibody and use thereof

Abstract

Provided are a bispecific antibody or an antigen-binding fragment thereof, a nucleic acid encoding the same, a cell comprising the nucleic acid, a composition comprising the bispecific antibody or antigen-binding fragment thereof, the nucleic acid and/or the cell, and related applications of the bispecific antibody or antigen-binding fragment thereof in the treatment of cancer.

1 . A bispecific antibody or antigen-binding fragment thereof comprising:
 (a) a first antigen-binding portion or antigen-binding fragment thereof, the first antigen-binding portion comprises a first light chain and a first heavy chain, the first light chain is a κ light chain, the first antigen-binding portion comprises a first binding domain that binds to a first antigen; and   (b) a second antigen-binding portion or antigen-binding fragment thereof, the second antigen-binding portion comprises a second light chain and a second heavy chain, the second light chain is a λ light chain, the second antigen-binding portion comprises a second binding domain that binds to a second antigen.   
     
     
         2 . The bispecific antibody or antigen-binding fragment thereof according to  claim 1 , wherein the second antigen is a CD3 antigen;
 preferably, a second light chain variable region of the second antigen-binding portion has a Gln 40 Glu mutation (Vλ CD3 : Gln 40 Glu); and a second heavy chain variable region of the second antigen-binding portion has a Gln 39 Lys mutation (VH CD3 : Gln 39 Lys);   preferably, the second binding domain comprises a second light chain CDR selected from amino acid sequences of SEQ ID NOs: 7-9, 14, 15, 20, 21 or any variant thereof, and/or a second heavy chain CDR selected from amino acid sequences of SEQ ID NOs: 26-28, 31, 34, 40, 43, 46, 47 or any variant thereof; and   preferably, the second binding domain comprises a second light chain CDR1 selected from any of amino acid sequences of SEQ ID NOs: 7, 14 or any variant thereof, a second light chain CDR2 selected from any of amino acid sequences of SEQ ID NOs: 8, 15, 20 or any variant thereof, a second light chain CDR3 selected from any of amino acid sequences of SEQ ID NOs: 9, 21 or any variant thereof, and/or a second heavy chain CDR1 selected from any of amino acid sequences of SEQ ID NOs: 26, 31, 46 or any variant thereof, a second heavy chain CDR2 selected from any of amino acid sequences of SEQ ID NOs: 27, 47 or any variant thereof, a second heavy chain CDR3 selected from any of amino acid sequences of SEQ ID NOs: 28, 34, 37, 40, 43 of or any variant thereof;   preferably, the second light chain CDR of the second binding domain is selected from: the second light chain CDR1, CDR2 and CDR3 sequences respectively comprising amino acid sequences of SEQ ID NOs: 7, 8, 9; the second light chain CDR1, CDR2 and CDR3 respectively comprising amino acid sequences of SEQ ID NOs: 14, 15, 9; the second light chain CDR1, CDR2 and CDR3 respectively comprising amino acid sequences of SEQ ID NOs: 7, 8, 21; the second light chain CDR1, CDR2 and CDR3 respectively comprising amino acid sequences of SEQ ID NOs: 7, 20, 21; and/or the heavy chain CDR of the second binding domain is selected from the second heavy chains CDR1, CDR2 and CDR3 respectively comprising amino acid sequences of SEQ ID NOs: 26, 27, 28; the second heavy chains CDR1, CDR2 and CDR3 respectively comprising amino acid sequences of SEQ ID NOs: 31, 27, 28; the second heavy chains CDR1, CDR2 and CDR3 respectively comprising amino acid sequences of SEQ ID NOs: 31, 27, 34; the second heavy chains CDR1, CDR2 and CDR3 respectively comprising amino acid sequences of SEQ ID NOs: 31, 27, 37; the second heavy chains CDR1, CDR2 and CDR3 respectively comprising amino acid sequences of SEQ ID NOs: 31, 27, 40; the second heavy chains CDR1, CDR2 and CDR3 respectively comprising the amino acid sequences of SEQ ID NOs: 31, 27, 43; the second heavy chains CDR1, CDR2 and CDR3 respectively comprising the amino acid sequences of SEQ ID NOs: 46, 47, 28;   preferably, the second binding domain comprises a second light chain variable region selected from any of amino acid sequences of SEQ ID NOs: 5, 10, 12, 16, 18, 22 or any variant thereof, and/or a second heavy chain variable region selected from any of amino acid sequences of SEQ ID NOs: 24, 29, 32, 35, 38, 41, 44, 48, 50, 52 or any variant thereof,   preferably, the second binding domain comprises a second light chain variable region of an amino acid sequence of SEQ ID NO: 18 or any variant thereof, and a second heavy chain variable region of an amino acid sequence of SEQ ID NO: 24 or any variant thereof, preferably, the second binding domain comprises a second light chain variable region of an amino acid sequence of SEQ ID NO: 5 or any variant thereof, and a second heavy chain variable region of an amino acid sequence of SEQ ID NO: 48 or any variant thereof,   preferably, the second binding domain comprises a second light chain variable region of an amino acid sequence of SEQ ID NO: 18 or any variant thereof, and a second heavy chain variable region of an amino acid sequence of SEQ ID NO: 48 or any variant thereof, preferably, the second binding domain comprises a second light chain variable region of an amino acid sequence of SEQ ID NO: 5 or any variant thereof, and a second heavy chain variable region of an amino acid sequence of SEQ ID NO: 50 or any variant thereof,   preferably, the second binding domain comprises a second light chain variable region of an amino acid sequence of SEQ ID NO: 10 or any variant thereof, and a second heavy chain variable region of an amino acid sequence of SEQ ID NO: 50 or any variant thereof, preferably, the second binding domain comprises a second light chain variable region of an amino acid sequence of SEQ ID NO: 12 or any variant thereof, and a second heavy chain variable region of an amino acid sequence of SEQ ID NO: 50 or any variant thereof, preferably, the second binding domain comprises a second light chain variable region of an amino acid sequence of SEQ ID NO: 18 or any variant thereof, and a second heavy chain variable region of an amino acid sequence of SEQ ID NO: 50 or any variant thereof, preferably, the second light chain of the second antigen-binding portion is selected from any of amino acid sequences of SEQ ID NOs: 58 and 66; and/or the second heavy chain of the second antigen-binding portion is selected from any of amino acid sequences of SEQ ID NOs: 60 and 68; more preferably, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 58; and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 60; more preferably, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 66; and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 68.   
     
     
         3 . The bispecific antibody or antigen-binding fragment thereof according to  claim 1 , wherein the first antigen is a tumor antigen;
 preferably, the tumor antigen is selected from: CD19, CD20, CD22, CD30, CD38, CD72, CD180, CD171(L1CAM), CD123, CD133, CD138, CD37, CD70, CD79a, CD79b, CD56, CD74, CD166, CD71, CLL-1/CLECK12A, ROR1, BCMA, GPC3, mesothelin, CD33/IL3Ra, c-Met, PSCA, PSMA, glycolipid F77, EGFRvIII, GD-2, MY-ESO-1, Her2, Her3, MUC1, MUC17, Claudin18 or MAGEA3,   more preferably, the tumor associated antigen is selected from CD20, BCMA and GPC3.   
     
     
         4 . The bispecific antibody or antigen-binding fragment thereof according to  claim 1 , wherein the first antigen is a CD20 antigen;
 preferably, the first light chain variable region of the first antigen-binding portion has a Gln 38 Lys mutation (Vκ CD20 : Gln 38 Lys); more preferably, the first heavy chain variable region of the first antigen-binding portion has a Gln 39 Glu mutation (VH CD20 : Gln 39 Glu);   preferably, the first light chain variable region of the first antigen-binding portion has a Gln 38 Lys mutation (Vκ CD20 : Gln 38 Lys), and the first light chain constant region has Glu 23 Lys and Gln 124 Lys mutations (Vκ-Ck CD20 : Gln 38 Lys\Glu 123 Lys\Gln 124 Lys); more preferably, the first heavy chain variable region of the first antigen-binding portion has a Gln 39 Glu mutation (VH CD20 : Gln 39 Glu), and the first heavy chain constant region has Lys 152 Glu and Lys 218 Glu mutations (V H -C H 1 CD20 : Gln 39 Glu\Lys 152 Glu\Lys 218 Glu).   
     
     
         5 . The bispecific antibody or antigen-binding fragment thereof according to  claim 4 , wherein the first light chain of the first antigen-binding portion is selected from any of amino acid sequences of SEQ ID NOs: 54, 62, and 70; and/or the first heavy chain of the first antigen-binding portion is selected from any of amino acid sequences of SEQ ID NOs: 56, 64, and 72;
 preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 54, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 56;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 62, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 64;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 70, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 72;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 54, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 56, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 58, and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 60;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 62, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 64, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 66, and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 68, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 58, and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 60;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 70, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 72, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 66, and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 68;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 62, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 64, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 58, and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 60;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 54, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 56, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 66, and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 68.   
     
     
         6 . The bispecific antibody or antigen-binding fragment thereof according to  claim 1 , wherein the first antigen is a BCMA antigen;
 preferably, the first light chain variable region of the first antigen-binding portion has a Gln 42 Lys mutation (Vκ BCMA : Gln 42 Lys); more preferably, the first heavy chain variable region of the first antigen-binding portion has a Gln 39 Glu mutation (VH BCMA : Gln 39 Glu).   
     
     
         7 . The bispecific antibody or antigen-binding fragment thereof according to  claim 6 , wherein the first light chain of the first antigen-binding portion is selected from any of amino acid sequences of SEQ ID NOs: 80 and 84; and/or the first heavy chain of the first antigen-binding portion is selected from any of amino acid sequences of SEQ ID NOs: 82 and 86;
 preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 80; and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 82;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 84; and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 82;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 80; and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 86;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 84; and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 86;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 80, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 82, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 66, and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 68;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 84, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 82, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 66, and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 68;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 80, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 86, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 66, and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 68;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 84, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 86, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 66, and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 68.   
     
     
         8 . The bispecific antibody or antigen-binding fragment thereof according to  claim 1 , wherein the first antigen is a GPC3 antigen;
 preferably, the first light chain variable region of the first antigen-binding portion has Gln 43 Lys and Gln 39 Glu mutations (Vκ GPC3 : Gln 43 Lys; VH GPC3 : Gln 39 Glu).   
     
     
         9 . The bispecific antibody or antigen-binding fragment thereof according to  claim 8 , wherein the first light chain of the first antigen-binding portion is selected from any of amino acid sequences of SEQ ID NOs: 88 and 92; and/or the first heavy chain of the first antigen-binding portion is selected from any of amino acid sequences of SEQ ID NOs: 90 and 94;
 preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 88, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 90;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 92, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 94;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 88, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 90, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 66, and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 68;   preferably, the first light chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 92, and the first heavy chain of the first antigen-binding portion is the amino acid sequence of SEQ ID NO: 94, the second light chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 66, and the second heavy chain of the second antigen-binding portion is the amino acid sequence of SEQ ID NO: 68.   
     
     
         10 . The bispecific antibody or antigen-binding fragment thereof according to  claim 1 , wherein the Fc portion of the first antigen-binding portion and/or the second antigen-binding portion of the bispecific antibody adopts a knob-into-hole structure;
 preferably, the human IgG4 knob-into-hole structure is used;   preferably, the first antigen-binding portion and/or the second antigen-binding portion of the bispecific antibody further has a Ser 228 Pro mutation, Leu 235 Glu mutation and/or Pro 329 Ala mutation.   
     
     
         11 . A nucleic acid encoding the bispecific antibody or antigen-binding portion thereof according to  claim 1 ;
 preferably, the second antigen-binding portion binds to a CD3 antigen, the nucleic acid encoding the second light chain variable region of the second antigen-binding portion is selected from any of nucleotide sequences of SEQ ID NOs: 6, 11, 13, 17, 19 and 23; and/or the nucleic acid encoding the second heavy chain variable region of the second antigen-binding portion is selected from any of nucleotide sequences of ID NO: 25, 30, 33, 36, 39, 42, 45, 49, 51 and 53;   preferably, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from any of nucleotide sequences of ID NO: 59 and 67; and/or the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from any of nucleotide sequences of ID NO: 61 and 69; more preferably, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 59, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 61; more preferably, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 67, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 69;   preferably, the first antigen-binding portion binds to the CD20 antigen, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from any of nucleotide sequences of SEQ ID NOs: 55, 63 and 71; and/or the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from any of nucleotide sequences of SEQ ID NOs: 57, 65 and 73; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 55, and the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 57; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 63, and the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 65; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 71, and the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 73;   preferably, the first antigen-binding portion binds to a BCMA antigen, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from any of nucleotide sequences of SEQ ID NOs: 81 and 85; and/or the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from SEQ ID NOs: 83 and 87; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 81, and the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 83;   more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 85, and the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 83; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 81, and the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 87; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 85, and the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 87;   preferably, the first antigen-binding portion binds to a GPC3 antigen, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from any of nucleotide sequences of SEQ ID NOs: 89 and 93; and/or the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from any of nucleotide sequences of SEQ ID NOs: 91 and 95; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 89, and the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 91; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 93, and the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 95;   more preferably, the first antigen-binding portion of the bispecific antibody binds the CD20 antigen, the second antigen binds the CD3 antigen, and the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 55, the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 57, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 59, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 61; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 63, and the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 65, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 67, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 69, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 59, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 61; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 71, and the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 73, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 67, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 69; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 63, and the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 65, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 59, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 61; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 55, the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 57, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 67, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 69;   more preferably, the first antigen-binding portion of the bispecific antibody binds to the BCMA antigen, the second antigen binds to the CD3 antigen, and the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 81, the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 83, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 67, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 69; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 85, the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 83, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 67, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 69; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 81, the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 87, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 67, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 69; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 85, the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 87, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 67, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 69;   more preferably, the first antigen-binding portion of the bispecific antibody binds to the GPC3 antigen, the second antigen binds to the CD3 antigen, and the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 89, the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 91, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 67, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 69; more preferably, the nucleic acid encoding the first light chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 93, the nucleic acid encoding the first heavy chain of the first antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 95, the nucleic acid encoding the second light chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 67, and the nucleic acid encoding the second heavy chain of the second antigen-binding portion is selected from the nucleotide sequence of SEQ ID NO: 69.   
     
     
         12 . A vector comprising the nucleic acid according to  claim 11 . 
     
     
         13 . A cell comprising the nucleic acid according to  claim 11  or a vector comprising the nucleic acid. 
     
     
         14 . A composition comprising the bispecific antibody or antigen-binding portion thereof according to  claim 1 , a nucleic acid encoding the bispecific antibody or antigen-binding portion thereof, a vector comprising the nucleic acid and/or a cell comprising the nucleic acid or the vector. 
     
     
         15 . An antibody-drug conjugate comprising the bispecific antibody or antigen-binding portion thereof according to  claim 1  covalently attached to a therapeutic moiety;
 preferably, the therapeutic moiety is selected from a cytotoxic moiety, a chemotherapeutic agent, a cytokine, an immunosuppressant, an immunostimulant, a lytic peptide, or a radioisotope; 
 preferably, the cytotoxic moiety is selected from: paclitaxel; cytochalasin B; gramicidin D; ethidium bromide; emetine; mitomycin; etoposide; teniposide; vincristine; vinblastine; colchicine; doxorubicin; daunorubicin; dihydroxy anthracenedione; tubulin inhibitors such as maytansine or analogs or derivatives thereof; antimitotic agents such as monomethyl auristatin E or F or analogues or derivatives thereof, hareotoxin 10 or 15 or an analogue thereof, irinotecan or an analog thereof, mitoxantrone; mithramycin; actinomycin D; 1-dehydrotestosterone; glucocorticoids; procaine; tetracaine; lidocaine; propranolol; puromycin; calicheamicin or an analogue or derivative thereof, antimetabolites such as methotrexate, 6 mercaptopurine, 6 thioguanine, cytarabine, fludarabine, 5 fluorouracil, decadiazine, hydroxyurea, asparaginase, gemcitabine or cladribine; alkylating agents such as mechlorethamine, thiopurine, chlorambucil, melphalan, BSNU, CCNU, cyclophosphamide, busulfan, dibromomannitol, streptozotocin, DTIC, procarbazine, mitomycin C; platinum derivatives such as cisplatin or carboplatin; duocarmycin A, duocarmycin SA, rapamycin (CC-1065) or analogs or derivatives thereof, antibiotics such as actinomycin, bleomycin, daunorubicin, doxorubicin, idarubicin, mithramycin, mitomycin, mitoxantrone, plicomycin, AMC; pyrrolo [2, 1-c] [1, 4]-benzodiazepine(PDB); diphtheria toxins and related molecules such as diphtheria A chain and active fragments and hybrid molecules thereof, ricin toxins such as ricin A or deglycosylated ricin A chain toxins, cholera toxins, shiga-like toxins such as SLT I, SLT II, SLT IIV, LT toxins, C3 toxins, shiga toxins, pertussis toxins, tetanus toxins, soybean Bowman-Birk protease inhibitors,  pseudomonas  exotoxin, arolin, saporin, modeccin, gelsolin, abrin A chain, modeccin A chain, α-sarcin,  Aleurites fordii  proteins, caryophyllin proteins, pokeweed proteins such as PAPI, PAPII and PAP-S,  Momordica charantia  inhibitors, curcin, crotin,  Sapaonaria officinalis  inhibitors, gelonin, mitomycin, restrictocin, phenomycin and enomycin toxins; RNase; DNase I, staphylococcal endotoxin A; pokeweed antiviral protein; diphtheria toxin and  pseudomonas  endotoxin; 
 preferably, the cytokine is selected from IL-2, IL-4, IL-6, IL-7, IL-10, IL-12, IL-13, IL-15, IL-18, IL-23, IL-24, IL-27, IL-28a, IL-28b, IL-29, KGF, IFNa, IFN3, IFNy, GM-CSF, CD40L, Flt3 ligand, stem cell factor, ancestine and TNFa; 
 preferably, the radioisotope is selected from  3 H,  14 C,  15 N,  35 S,  67 Cu,  90 Y,  99 Tc,  125 ,  131 I,  186 Re,  188 Re,  211 At  212 Bi,  212 Pb,  213 Bi,  225  Ac and  227 Th. 
 
     
     
         16 . A kit comprising the bispecific antibody or antigen-binding portion thereof according to  claim 1 , or a nucleic acid encoding the bispecific antibody or antigen-binding portion thereof, or a vector comprising the nucleic acid, or a cell comprising the nucleic acid or the vector. 
     
     
         17 . A method of diagnosing, treating or preventing diseases and conditions associated with a tumor antigen, wherein the method includes the steps of: administering to a subject a therapeutically effective amount of the bispecific antibody or antigen-binding fragment thereof according to  claim 1  or a nucleic acid molecule encoding the bispecific antibody or antigen-binding portion thereof, or a vector or a cell comprising the nucleic acid, or a pharmaceutical composition;
 wherein the pharmaceutical composition comprises any one of the bispecific antibody or antigen-binding fragment thereof, a nucleic acid encoding the bispecific antibody or antigen-binding portion thereof, a vector comprising the nucleic acid, and a cell comprising the nucleic acid or the vector; 
 preferably, the tumor antigen is CD20, the tumor antigen-related disease is a CD20-related disease; preferably, the CD20-related disease including B-cell diseases, such as B cell proliferative disorders, in particular CD20-positive B-cell disorders; preferably, the disease is selected from non-Hodgkin's lymphoma (NHL), acute lymphocytic leukemia (ALL), chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), mantle cell lymphoma (MCL), marginal zone lymphoma (MZL), and multiple myeloma (MM) and Hodgkin's lymphoma (HL); 
 preferably, the tumor antigen is BCMA, the tumor antigen-related disease is a BCMA-related disease; preferably, the BCMA-related disease including B-cell disease; preferably, the disease is cancer; more preferably, the cancer is a B-cell related cancer selected from multiple myeloma, malignant plasmacytoma, hodgkin's lymphoma, nodular lymphocyte-predominant Hodgkin's lymphoma, Kahler's disease and myeloid leukemia, plasma cell leukemia, plasmacytoma, B-cell prolymphocytic leukemia, hairy cell leukemia, B-cell non-Hodgkin's lymphoma (NHL), acute myelogenous leukemia (AML), chronic lymphocytic leukemia (CLL), acute lymphocytic leukemia (ALL), chronic myelogenous leukemia (CML), follicular lymphoma, burkitt lymphoma, marginal zone lymphoma, mantle cell lymphoma, large cell lymphoma, precursor B-lymphocyte lymphoma, myeloid leukemia, waldenstrom's macroglobulinemia, diffuse large B cell lymphoma, follicular lymphoma, marginal zone lymphoma, mucosa-related lymphoid tissue lymphoma, small cell lymphocytic lymphoma, mantle cell lymphoma, burkitt lymphoma, primary mediastinal (thymic) large B cell lymphoma, lymphoplasmacytic lymphoma, waldenstrom's macroglobulinemia, lymph node marginal zone B cell lymphoma, splenic marginal zone lymphoma, intravascular large B-cell lymphoma, primary effusion lymphoma, lymphomatoid granulomatosis, large B-cell lymphoma rich in T-cells/histiocytes, primary central nervous system lymphoma, primary cutaneous diffuse large B-cell lymphoma (leg type), elderly EBV-positive diffuse large B-cell lymphoma, inflammation-related diffuse large B-cell lymphoma, intravascular large B-cell lymphoma, ALK-positive large B-cell lymphoma, plasmablast-cell lymphoma, large B-cell lymphoma arising in HHV8-related multicenter Castleman's disease, unclassified B-cell lymphoma with intermediate features between diffuse large B-cell lymphoma and Burkitt's lymphoma, unclassified B-cell lymphoma with intermediate features between diffuse large B-cell lymphoma and classic Hodgkin's lymphoma, and other B-cell-related lymphomas; more preferably, the B-cell disease is a B-cell disorder; 
 preferably, the plasma cell disorder is selected from: multiple myeloma, plasmacytoma, plasma cell leukemia, macroglobulinemia, amyloidosis, waldenstrom's macroglobulinemia, solitary plasmacytoma of the bone, extramedullary plasmacytoma, osteosclerotic myeloma, heavy chain disease, monoclonal gammopathy of unclear significance, and multiple myeloma of stasis type; 
 preferably, the disease is an autoimmune disorder such as systemic lupus erythematosus or rheumatoid arthritis; 
 preferably, the tumor antigen is GPC3, the tumor antigen-related disease is a GPC3-related disease; preferably, the GPC3-related disease includes tumors; preferably, the tumor is a cancer; 
 more preferably, the cancer is a GPC3-positive cancer, which, for example, can be a GPC3-positive liver cancer, a GPC3-positive hepatocellular carcinoma, a GPC3-positive pancreatic cancer, a GPC3-positive lung cancer, a GPC3-positive colon cancer, a GPC3-positive breast cancer, a GPC3-positive prostate cancer, a GPC3-positive leukemia, or a GPC3-positive lymphoma. 
 
     
     
         18 . A kit comprising the composition according to  claim 14 . 
     
     
         19 . A kit comprising the antibody-drug conjugate according to  claim 15 .