Polynucleotides encoding anti-KIT antibodies
Provided herein, in one aspect, are antibodies that immunospecifically bind to a human KIT antigen comprising the fourth and/or fifth extracellular Ig-like domains (that is, D4 and/or D5 domains), polynucleotides comprising nucleotide sequences encoding such antibodies, and expression vectors and host cells for producing such antibodies. The antibodies can inhibit KIT activity, such as ligand-induced receptor phosphorylation. Also provided herein are kits and pharmaceutical compositions comprising antibodies that specifically bind to a KIT antigen, as well as methods of treating or managing a KIT-mediated disorder or disease and methods of diagnosing a KIT-mediated disorder or disease using the antibodies described herein.
1. An polynucleotide comprising nucleotide sequences encoding a VH chain region, a VL chain region, or both a VL chain region and a VH chain region, of an antibody or an antigen-binding fragment thereof, which immunospecifically binds to human KIT (SEQ ID NO: 15) and comprises:
(i) a variable light (“VL”) chain region comprising a VL CDR1, VL CDR2, and VL CDR3 comprising the amino acid sequences of SEQ ID NO: 20, SEQ ID NO: 21, and SEQ ID NO: 22, respectively; and
(ii) a variable heavy (“VH”) chain region comprising a VH CDR1, VH CDR2, and VH CDR3 comprising the amino acid sequences of SEQ ID NO: 23, SEQ ID NO: 24, and SEQ ID NO: 25, respectively.
2. The polynucleotide of claim 1 , wherein the polynucleotide comprises a nucleotide sequence encoding a VH chain region, a VL chain region, or both a VL chain region and a VH chain region, of an antibody or an antigen-binding fragment thereof comprising:
(i) a VL chain region comprising the amino acid sequence of SEQ ID NO: 2; and
(ii) a VH chain region comprising the amino acid sequence of SEQ ID NO: 3 or 5.
3. The polynucleotide of claim 1 , wherein the polynucleotide comprises a nucleotide sequence encoding a VH chain region, a VL chain region, or both a VL chain region and a VH chain region, of an antibody or an antigen-binding fragment thereof which immunospecifically binds to human KIT (SEQ ID NO: 15), wherein said polynucleotide comprises the nucleotide sequence of SEQ ID NO: 8 or 9, or the nucleotide sequences of SEQ ID NOs: 8 and 9.
4. The polynucleotide of claim 1 , wherein the polynucleotide comprises a nucleotide sequence encoding a heavy chain, a light chain, or both a light chain and a heavy chain, of an antibody or an antigen-binding fragment thereof which immunospecifically binds to human KIT (SEQ ID NO: 15), wherein said polynucleotide comprises the nucleotide sequence of SEQ ID NO: 10 or 11, or the nucleotide sequences of SEQ ID NOs: 10 and 11.
5. An expression vector comprising the polynucleotide of any one of claims 1 and 2 - 4 .
6. The expression vector of claim 5 , which is a mammalian expression vector.
7. A host cell comprising the expression vector of claim 5 .
8. A hybridoma cell producing an antibody or an antigen-binding fragment thereof, which immunospecifically binds to human KIT (SEQ ID NO: 15) and comprises:
(i) a VL chain region comprising a VL CDR1, VL CDR2, and VL CDR3 comprising the amino acid sequences of SEQ ID NO: 20, SEQ ID NO: 21, and SEQ ID NO: 22, respectively; and
(ii) a VH chain region comprising a VH CDR1, VH CDR2, and VH CDR3 comprising the amino acid sequences of SEQ ID NO: 23, SEQ ID NO: 24, and SEQ ID NO: 25, respectively.
9. A method of making an antibody or an antigen-binding fragment thereof which immunospecifically binds to human KIT (SEQ ID NO: 15) comprising culturing the host cell of claim 7 .
10. The method claim 9 further comprising purifying the antibody obtained from said host cell.
11. A host cell comprising the expression vector of claim 6 .
12. A host cell comprising (i) the polynucleotide of any one of claims 1 and 2 - 6 that comprises nucleotide sequences encoding a VL chain region and a VH chain region of an antibody or an antigen-binding fragment thereof; or (ii) a first polynucleotide of any one of claims 1 and 2 - 6 that comprises a nucleotide sequence encoding a VH chain region of an antibody or an antigen-binding fragment thereof, and a second polynucleotide of any one of claims 1 and 2 - 6 that comprises a nucleotide sequence encoding a VL chain region of said antibody or antigen-binding fragment thereof.
13. The hybridoma cell of claim 8 , wherein:
(i) the VL chain region comprises the amino acid sequence of SEQ ID NO: 2; and
(ii) the VH chain region comprises the amino acid sequence of SEQ ID NO: 3 or 5.
14. A method of making an antibody or an antigen-binding fragment thereof which immunospecifically binds to human KIT (SEQ ID NO: 15) comprising culturing the host cell of claim 11 .
15. The method claim 14 further comprising purifying the antibody obtained from said host cell.
16. A method of making an antibody or an antigen-binding fragment thereof which immunospecifically binds to human KIT (SEQ ID NO: 15) comprising culturing the host cell of claim 12 .
17. The method claim 16 further comprising purifying the antibody obtained from said host cell.
18. A method of making an antibody or an antigen-binding fragment thereof which immunospecifically binds to human KIT (SEQ ID NO: 15) comprising culturing the hybridoma cell of claim 8 .
19. The method claim 18 further comprising purifying the antibody obtained from said hybridoma cell.
20. A method of making an antibody or an antigen-binding fragment thereof which immunospecifically binds to human KIT (SEQ ID NO: 15) comprising culturing the hybridoma cell of claim 13 .
21. The method claim 20 further comprising purifying the antibody obtained from said hybridoma cell.
22. The polynucleotide of any one of claims 1 and 2 - 6 , wherein the antibody is a humanized monoclonal antibody.
23. The polynucleotide of any one of claims 1 and 2 - 6 , wherein the antibody is a monoclonal antibody.
24. The polynucleotide of any one of claims 1 and 2 - 6 , wherein the antibody comprises an Fc region of a human IgG1 or IgG4 antibody.
25. The polynucleotide of any one of claims 1 and 2 - 6 , wherein the antibody is a humanized antibody.
26. The polynucleotide of any one of claims 1 and 2 - 6 , wherein the antibody further comprises a human heavy chain constant region.
27. The polynucleotide of claim 26 , wherein the human heavy chain constant region is a human gamma heavy chain constant region.
28. The polynucleotide of claim 26 , wherein the human heavy chain constant region is an IgG1 or IgG4 human heavy chain constant region.
29. The polynucleotide of any one of claims 1 and 2 - 6 , wherein the antibody further comprises a human light chain constant region.
30. The polynucleotide of claim 29 , wherein the human light chain constant region is a human kappa light chain constant region.
31. The polynucleotide of any one of claims 1 and 2 - 6 , wherein the antibody further comprises a human light chain constant region and a human heavy chain constant region.
32. The polynucleotide of claim 31 , wherein the human light chain constant region comprises the amino acid sequence of SEQ ID NO: 12 and the human heavy chain constant region comprises the amino acid sequence of SEQ ID NO: 13.
33. The polynucleotide of claim 31 , wherein the human light chain constant region is a human kappa light chain constant region and the human heavy chain constant region is a human gamma heavy chain constant region.
34. The polynucleotide of claim 31 , wherein the human light chain constant region is a human kappa light chain constant region and the human heavy chain constant region is an IgG1 or IgG4 human heavy chain constant region.