Fully human anti-mesothelin antibodies and immune effector cells targeting mesothelin

1. An antibody that specifically binds to mesothelin, wherein the antibody is at least one selected from the group consisting of:

(a) an antibody comprising:

a heavy chain variable region having VH CDR1 comprising the amino acid sequence of SEQ ID NO: 54, VH CDR2 comprising the amino acid sequence of SEQ ID NO: 55, and VH CDR3 comprising the amino acid sequence of SEQ ID NO: 56; and

a light chain variable region having VL CDR1 comprising the amino acid sequence of SEQ ID NO: 51, VL CDR2 comprising the amino acid sequence of SEQ ID NO: 52, and VL CDR3 comprising the amino acid sequence of SEQ ID NO: 53,

(b) an antibody comprising:

a heavy chain variable region having VH CDR1 comprising the amino acid sequence of SEQ ID NO: 60, VH CDR2 comprising the amino acid sequence of SEQ ID NO: 61, and VH CDR3 of the amino acid sequence of SEQ ID NO: 62; and

a light chain variable region having VL CDR1 comprising the amino acid sequence of SEQ ID NO: 57, VL CDR2 comprising the amino acid sequence of SEQ ID NO: 58 and VL CDR3 of the amino acid of ID NO: 59,

(c) an antibody comprising:

a heavy chain variable region comprising the amino acid sequence shown in positions 1 to 123 of SEQ ID NO: 6; and

a light chain variable region comprising the amino acid sequence shown in positions 139-254 of SEQ ID NO: 6, and

(d) an antibody comprising:

a heavy chain variable region comprising the amino acid sequence shown in positions 1 to 124 of SEQ ID NO: 8; and

a light chain variable region comprising the amino acid sequence shown in positions 140-247 of SEQ ID NO: 8.

2. A nucleic acid encoding the antibody of claim 1 .

3. An expression vector comprising the nucleic acid of claim 2 .

4. An isolated host cell, comprising the expression vector comprising the nucleic acid encoding the antibody of claim 1 or having the nucleic acid encoding the antibody of claim 1 integrated into the genome.

5. A method, comprising a step of preparing a targeted drug, antibody-drug conjugate, or a polyfunctional antibody that specifically targets tumor cells expressing mesothelin, or preparing a reagent for diagnosing a tumor expressing mesothelin, or preparing a chimeric antigen receptor-modified immune cell by using the antibody of claim 1 .

6. A pharmaceutical composition, comprising:

(a) the antibody of claim 1 or a nucleic acid encoding the antibody of claim 1 ;

(b) an immunoconjugate comprising the antibody of claim 1 and a functional molecule linked thereto or a nucleic acid encoding the immunoconjugate,

wherein the functional molecule includes at least one selected from the group consisting of a molecule that targets a tumor surface marker, a tumor-suppressing molecule, a molecule that targets a surface marker of an immune cell, and a detectable label;

(c) a chimeric antigen receptor comprising in sequential order: the antibody of claim 1 , a transmembrane region, and an intracellular signal region;

(d) a nucleic acid encoding the chimeric antigen receptor; or

(e) a genetically modified immune cell, wherein the genetically modified immune cell is transduced with a nucleic acid encoding a chimeric antigen receptor, or an expression vector comprising the nucleic acid, or a virus comprising the expression vector,

wherein the chimeric antigen receptor comprises in sequential order: the antibody of claim 1 , a transmembrane region, and an intracellular signal region, and the genetically modified immune cell expresses the chimeric antigen receptor on a surface thereof.

7. A chimeric antigen receptor, wherein the chimeric antigen receptor comprises

(a) sequentially linked: the antibody of claim 1 ; a transmembrane region; and an intracellular signal region, or

(b) the following sequentially linked antibody, transmembrane region, and intracellular signal region:

(i) the antibody of claim 1 , CD8 and CD3ζ;

(ii) the antibody of claim 1 , CD8, CD137 and CD3ζ;

(iii) the antibody of claim 1 , the transmembrane region of CD28 molecule, the intracellular signal region of CD28 molecule and CD3ζ; or

(iv) the antibody of claim 1 , the transmembrane region of CD28 molecule, the intracellular signal region of CD28 molecule, CD137 and CD3ζ.

8. The chimeric antigen receptor of claim 7 , wherein the antibody is a single chain antibody.

9. The chimeric antigen receptor of claim 7 , wherein the chimeric antigen receptor has:

SEQ ID NO: 41 or the amino acid sequence shown in positions 22-353 thereof;

SEQ ID NO: 42 or the amino acid sequence shown in positions 22-454 thereof;

SEQ ID NO: 43 or the amino acid sequence shown in positions 22-498 thereof;

SEQ ID NO: 44 or the amino acid sequence shown in positions 22-501 thereof;

SEQ ID NO: 45 or the amino acid sequence shown in positions 22-543 thereof;

SEQ ID NO: 46 or the amino acid sequence shown in positions 22-346 thereof;

SEQ ID NO: 47 or the amino acid sequence shown in positions 22-447 thereof;

SEQ ID NO: 48 or the amino acid sequence shown in positions 22-491 thereof;

SEQ ID NO: 49 or the amino acid sequence shown in positions 22-494 thereof; or

SEQ ID NO: 50 or the amino acid sequence shown in positions 22-536 thereof.

10. A nucleic acid encoding the chimeric antigen receptor of claim 7 .

11. An expression vector comprising the nucleic acid of claim 10 .

12. A virus, wherein the virus comprises the expression vector of claim 11 .

13. A method for a preparation of genetically modified immune cell targeting a mesothelin-expressing tumor, comprising a step of obtaining a nucleic acid encoding an chimeric antigen receptor, or an expression vector comprising the nucleic acid, or a virus comprising the expression vector,

wherein the chimeric antigen receptor comprises sequentially linked: the antibody of claim 1 , a transmembrane region, and an intracellular signal region.

14. The method of claim 13 , wherein the mesothelin-expressing tumor includes at least one selected from the group consisting of pancreatic cancer, ovarian cancer and thymus mesothelioma.

15. The chimeric antigen receptor of claim 7 , wherein the intracellular signal region includes at least one selected from the group consisting of intracellular signal region sequences of CD3ζ, FcεRIγ, CD27, CD28, CD137, CD134, MyD88, CD40, and a combination thereof.

16. A genetically modified immune cell, wherein the genetically modified immune cell is transduced with a nucleic acid encoding a chimeric antigen receptor, or an expression vector comprising the nucleic acid, or a virus comprising the expression vector,

wherein the chimeric antigen receptor comprises sequentially linked: the antibody of claim 1 ; a transmembrane region; and an intracellular signal region,

the chimeric antigen receptor is expressed on a surface of the genetically modified immune cell.

17. The genetically modified immune cell of claim 16 , wherein the genetically modified immune cell further contains an encoding sequence of an exogenous cytokine;

the genetically modified immune cell further expresses another chimeric antigen receptor that does not contain CD3ζ but contains the intracellular signaling domain of CD28, the intracellular signaling domain of CD137, or a combination thereof;

the genetically modified immune cell further expresses a chemokine receptor;

the genetically modified immune cell further expresses siRNA capable of reducing expression of PD-1 or a protein which blocks PD-L1;

the genetically modified immune cell further expresses a safety switch; or

the genetically modified illumine cell are genetically modified T lymphocyte, NK cell, or NKT cell.

18. The genetically modified immune cell of claim 17 , wherein the exogenous cytokine includes IL-12, IL-15, or IL-21, or

the chemokine receptor includes CCR2, or

the safety switch includes iCaspase-9, truncated EGFR, or RQR8.

19. A multi-functional immunoconjugate, wherein the multi-functional immunoconjugate comprises:

the antibody of claim 1 ; and

a functional molecule linked thereto,

wherein the functional molecule includes at least one selected from the group consisting of a molecule that targets a tumor surface marker, a tumor-suppressing molecule, a molecule that targets a surface marker of an immune cell, and a detectable label.

20. A nucleic acid encoding the multi-functional immunoconjugate of claim 19 .

21. A method, comprising a step of preparing an antineoplastic agent or an agent for diagnosis of tumors that express mesothelin, or a

chimeric antigen receptor modified immune cell by using the multi-functional immunoconjugate of claim 19 .

22. The multi-functional immunoconjugate of claim 19 , wherein the molecule that targets the tumor surface marker is an antibody or ligand that binds to a tumor surface marker; or

the tumor-suppressing molecule is an anti-tumor cytokine or an anti-tumor toxin; or

the detectable label includes a fluorescent label or a chromogenic label.

23. The multi-functional immunoconjugate of claim 22 , wherein the anti-tumor cytokine includes IL-12, IL-15, IFN-beta, ear TNF-alpha, and

the antibody that binds to a tumor surface marker refers to an antibody that recognizes an antigen other than mesothelin, and the antigen other than mesotheline includes EGFR, EGFRvIII, mesothelin, HER2, EphA2, Her3, EpCAM, MUC1, MUC16, CEA, Claudin 18.2, folate receptor, Claudin 6, CD3, WT1, NY-ESO-1, MAGE 3, ASGPR1, or CDH16.

24. The method of claim 21 , wherein the chimeric antigen receptor modified immune cell is modified from an immune cell, and the immune cell includes T lymphocyte, NK cell, or NKT lymphocyte.

25. A multi-functional immunoconjugate comprising:

the antibody of claim 1 ; and

a functional molecule linked thereto,

wherein the functional molecule includes at least one selected from the group consisting of a molecule that targets a tumor surface marker, a tumor-suppressing molecule, a molecule that targets a surface marker of an immune cell, and a detectable label;

the molecule that targets the surface marker of the immune cell is an antibody that binds to a T cell surface marker and forms a T-cell engaging bifunctional antibody with the antibody of claim 1 .

26. The multi-functional immunoconjugate of claim 25 , wherein the molecule that targets the tumor surface marker is an antibody or ligand that binds to a tumor surface marker; or

the tumor-suppressing molecule is an anti-tumor cytokine or an anti-tumor toxin; or

the detectable label includes a fluorescent label or a chromogenic label.

27. The multi-functional immunoconjugate of claim 26 , wherein the anti-tumor cytokine includes IL-12, IL-15, IFN-beta, or TNT-alpha.

28. The multi-functional immunoconjugate of claim 26 , wherein the antibody that binds to a tumor surface marker refers to an antibody that recognizes an antigen other than mesothelin, and the antigen other than mesothelin includes EGFR EGFRvIII, mesothelin, HE2, EphA2, Her3, EpCAM, MUC1, MUC16, CEA, Claudin 18.2, folate receptor, Claudin 6, CD3, WT1, NY-ESO-1, MAGE 3, ASGPR1, or CDH16.

29. The multi-functional immunoconjugate of claim 25 , wherein the antibody that binds to a T cell surface marker is an anti-CD3 antibody.

30. The multi-functional immunoconjugate of claim 25 , wherein the multi-functional immunoconjugate is a fusion polypeptide and further comprises a linker peptide between the antibody of claim 1 and the functional molecule linked thereto.