Cytotoxic immunoglobulin
The invention relates to a cytotoxic modular antibody with a molecular weight of up to 60 kD, specifically binding to a cell surface target with a binding affinity of Kd<10 −8 M, a method of producing such antibody and its use as a therapeutic.
1. An isolated protein that binds specifically to human Her2, wherein the isolated protein comprises two polypeptides, wherein each polypeptide comprises a human IgG1 heavy chain fragment comprising a CH2 domain and a CH3 domain, wherein the CH3 domain comprises an AB loop comprising the amino acid sequence of SEQ ID NO: 191, a CD loop comprising the amino acid sequence of SEQ ID NO: 241 and an EF loop comprising the amino acid sequence of SEQ ID NO: 370.
2. The isolated protein of claim 1 , wherein the CH3 domain comprises the amino acid sequence of the CH3 domain in SEQ ID NO: 1 or SEQ ID NO: 440 exclusive of that of loops AB and EF.
3. The isolated protein of claim 1 , wherein the CH2 domain comprises the amino acid sequence of the CH2 domain in SEQ ID NO: 1.
4. The isolated protein of claim 2 , wherein the CH2 domain comprises the amino acid sequence of the CH2 domain in SEQ ID NO: 1.
5. The isolated protein of claim 1 , wherein the human IgG1 heavy chain fragment comprises a hinge.
6. The isolated protein of claim 1 , wherein the human IgG1 heavy chain fragment comprises the amino acid sequence SEQ ID NO: 1 exclusive of that of loops AB and EF.
7. The isolated protein of claim 1 , wherein the two polypeptides are connected by a disulfide bond.
8. The isolated protein of claim 7 , wherein the two polypeptides are connected by 2 disulfide bonds.
9. The isolated protein of claim 1 , which binds to human Her2 with a binding affinity of Kd<10 −8 M.
10. The isolated protein of claim 1 , which is cytotoxic.
11. The isolated protein of claim 10 , which triggers at least one of antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), complement dependent cytotoxicity (CDC), or apoptotic activity.
12. The isolated protein of claim 1 , having a molecular weight of up to 60 kD.
13. An isolated protein that specifically binds to human Her2, wherein the isolated protein comprises two polypeptides, wherein each polypeptide comprises a human IgG1 heavy chain fragment comprising a CH2 domain and a CH3 domain, wherein the CH3 domain comprises an AB loop comprising the amino acid sequence of SEQ ID NO: 191, a CD loop comprising the amino acid sequence of SEQ ID NO: 241 and an EF loop comprising the amino acid sequence of SEQ ID NO: 370; and wherein the isolated protein has a molecular weight of up to 60 kD, a binding affinity of Kd<10 −8 M and is cytotoxic.
14. A pharmaceutical composition comprising the isolated protein of claim 1 and a pharmaceutically acceptable carrier.
15. The isolated protein of claim 10 , which triggers apoptotic activity.
16. The isolated protein of claim 13 , wherein the CH3 domain comprises the amino acid sequence of the CH3 domain in SEQ ID NO: 1 or SEQ ID NO: 440, exclusive of that of loops AB and EF.
17. The isolated protein of claim 13 , wherein the CH2 domain comprises the amino acid sequence of the CH2 domain in SEQ ID NO: 1.
18. The isolated protein of claim 16 , wherein the CH2 domain comprises the amino acid sequence of the CH2 domain in SEQ ID NO: 1.
19. The isolated protein of claim 13 , wherein the human IgG1 heavy chain fragment comprises a hinge.
20. The isolated protein of claim 13 , wherein the two polypeptides are connected by a disulfide bond.
21. The isolated protein of claim 20 , wherein the two polypeptides are connected by 2 disulfide bonds.
22. The isolated protein of claim 13 , which triggers apoptotic activity.
23. The isolated protein of claim 13 , wherein the polypeptides are connected by a disulfide bond, and wherein the CH2 domain comprises the amino acid sequence of the CH2 domain of SEQ ID NO: 1 and the CH3 domain comprises the amino acid sequence of the CH3 domain of SEQ ID NO: 1 or SEQ ID NO: 440 exclusive of that of loops AB and EF.
24. The isolated protein of claim 23 , which triggers apoptotic activity.
25. The isolated protein of claim 23 , wherein the AB loop consists of the amino acid sequence of SEQ ID NO: 191, the CD loop consists of the amino acid sequence of SEQ ID NO: 241 and the EF loop consists of the amino acid sequence of SEQ ID NO: 370.
26. The isolated protein of claim 25 , which triggers apoptotic activity.
27. The isolated protein of claim 13 , wherein the polypeptides are connected by 2 disulfide bonds, and wherein the CH2 domain comprises the amino acid sequence of the CH2 domain of SEQ ID NO: 1 and the CH3 domain comprises the amino acid sequence of the CH3 domain of SEQ ID NO: 1 or SEQ ID NO: 440 exclusive of that of loops AB and EF.
28. The isolated protein of claim 27 , which triggers apoptotic activity.
29. The isolated protein of claim 27 , wherein the AB loop consists of the amino acid sequence of SEQ ID NO: 191, the CD loop consists of the amino acid sequence of SEQ ID NO: 241 and the EF loop consists of the amino acid sequence of SEQ ID NO: 370.
30. The isolated protein of claim 29 , which triggers apoptotic activity.