Humanized antibodies against c-Kit
The invention provides antibodies specifically binding to c-Kit and methods of using such antibodies in stem cell replacement and treatment of cancer.
1. A nucleic acid molecule encoding an antibody specifically binding to human c-Kit comprising a mature heavy variable region comprising CDRs H1, H2 and H3 as defined by Kabat of SEQ ID NOS:14-16 respectively, and a mature light chain variable region comprising CDRs L1, L2 and L3 as defined by Kabat of SEQ ID NOS:36-38 respectively.
2. The nucleic acid molecule of claim 1 , wherein the mature heavy chain variable region shows at least 95% sequence identity to SEQ ID NO:13, and the mature light chain variable region shows at least 95% sequence identity to SEQ ID NO:53, wherein any variation from SEQ ID NOS:13 and 53 is outside the CDRs as defined by Kabat.
3. The nucleic acid molecule of claim 2 , wherein heavy chain position 1 by Kabat numbering is E.
4. The nucleic acid molecule of claim 2 , wherein the following positions of the mature light chain variable region according to Kabat numbering are occupied by amino acids as follows: Position 9 occupied by L; Position 12 occupied by P; Position 14 occupied by T; Position 15 occupied by P; Position 18 occupied by P; Position 20 occupied by S; Position 22 occupied by S; Position 37 occupied by L; Position 43 occupied by S; Position 45 occupied by Q; Position 74 occupied by K; Position 77 occupied by R; Position 78 occupied by V; Position 79 occupied by E; and Position 84 occupied by G.
5. The nucleic acid molecule of claim 1 , wherein the mature heavy chain variable region has the amino acid sequence of SEQ ID NO:13 except that position 1 can be E, and the mature light chain variable region has the amino acid sequence of SEQ ID NO:53.
6. The nucleic acid molecule of claim 1 , wherein the mature heavy chain variable region is linked to a heavy chain constant region and the mature light chain variable region is linked to a mature light chain constant region.
7. The nucleic acid molecule of claim 6 , wherein the heavy chain constant region is human IgG1.
8. The nucleic acid molecule of claim 1 , wherein the mature heavy chain variable region shows at least 98% sequence identity to SEQ ID NO: 13 and the mature light chain variable region shows at least 98% sequence identity to SEQ ID NO:53, wherein any variation from SEQ ID NOS: 13 and 53 is outside the CDRs as defined by Kabat.
9. The nucleic acid molecule of claim 5 , wherein the mature heavy chain variable region is linked to a heavy chain constant region and the mature light chain variable region is linked to a mature light chain constant region.
10. The nucleic acid molecule of claim 9 , wherein the heavy chain constant region is human IgG1.
11. An expression vector comprising the nucleic acid molecule of claim 1 .
12. A cell comprising the expression vector of claim 11 .
13. The cell of claim 12 , wherein the cell is a mammalian cell.
14. The cell of claim 13 , wherein the mammalian cell is selected from a CHO cell, a COS cell, a HeLa cell, HEK293 cell and an L cell.