Glycosylation engineering of antibodies for improving antibody-dependent cellular cytotoxicity

1. A glycoengineered, recombinant antibody comprising an IgG Fc region containing N-linked oligosaccharides, wherein said antibody is isolated from a Chinese Hamster Ovary host cell and has been engineered to have an increased ratio of GlcNAc residues to fucose residues in the Fc region compared to a corresponding antibody produced by a Chinese Hamster Ovary host cell that has not been glycoengineered, and wherein said antibody has increased Fc-mediated cellular cytotoxicity as a result of said glycoengineering.

2. A glycoengineered recombinant antibody according to claim 1 , wherein said GlcNAc residues are bisecting.

3. A glycoengineered, recombinant antibody according to claim 1 , wherein said GlcNAc residues are bisecting and wherein said bisected oligosaccharides are of complex type.

4. A glycoengineered, recombinant antibody according to claim 1 , wherein said GlcNAc residues are bisecting and wherein said bisected oligosaccharides are of hybrid type.

5. A glycoengineered, recombinant antibody according to claim 1 , wherein the predominant N-linked oligosaccharide in the Fc region is nonfucosylated.

6. A glycoengineered, recombinant antibody according to claim 1 , wherein said antibody is a chimeric antibody.

7. A glycoengineered, recombinant antibody according to claim 1 , wherein said antibody is a humanized antibody.

8. A glycoengineered, recombinant antibody according to claim 1 , wherein said antibody is an antibody fragment that contains a Fc region.

9. A glycoengineered, recombinant antibody according to claim 1 , wherein said antibody is a fusion protein that includes a Fc region of an immunoglobulin.

10. A glycoengineered, recombinant antibody according to claim 1 , wherein the predominant N-linked oligosaccharide in the Fc region is not a high-mannose structure.

11. A glycoengineered, recombinant antibody according to claim 1 , wherein said Chinese Hamster Ovary host cell has been genetically manipulated to have altered activity of at least one glycoprotein-modifying glycosyltransferase.

12. A glycoengineered, recombinant antibody according to claim 1 , wherein said antibody is a therapeutic antibody.

13. A glycoengineered, recombinant antibody according to claim 1 , wherein said antibody selectively binds to an antigen expressed by cancer cells.

14. A glycoengineered, recombinant antibody according to claim 12 , wherein said antibody is a monoclonal antibody.

15. A glycoengineered recombinant antibody according to claim 12 , wherein said antibody is a selected from the group consisting of: an anti-CD20 antibody, an anti-human neuroblastoma antibody, an anti-human renal cell carcinoma antibody, an anti-HER2 antibody, an anti-human colon, lung, and breast carcinoma antibody, an anti-human 17-1A antigen antibody, a humanized anti-human colorectal tumor antibody, an anti-human melanoma antibody, and an anti-human squamous-cell carcinoma antibody.

16. A glycoengineered, recombinant antibody according to claim 1 , wherein the majority of the N-linked oligosaccharides in the Fc region of said antibody are bisected.

17. A glycoengineered, recombinant antibody according to claim 1 , wherein the majority of the N-linked oligosaccharides in the Fc region of said antibody are nonfucosylated.

18. A glycoengineered, recombinant antibody according to claim 1 , wherein the majority of the N-linked oligosaccharides in said Fc region of said antibody are bisected, nonfucosylated.

19. A glycoengineered, recombinant antibody according to claim 1 , wherein said antibody is produced by a process comprising:

(a) providing a Chinese Hamster Ovary host cell comprising at least one nucleic acid encoding a recombinant anti body;

(b) genetically manipulating said host cell to alter the activity in said host cell of at least one glycoprotein-modifying glycosyltransferase;

(c) culturing said host cell under conditions which, permit expression of the glycoengineered, recombinant antibody; and

(d) isolating said glycoengineered, recombinant antibody.

20. A glycoengineered, recombinant antibody according to claim 11 , wherein said antibody is a therapeutic monoclonal antibody having a human Fc region and that selectively binds an antigen expressed by cancer cells, and wherein the majority of oligosaccharides in the Fc region of said antibody are nonfucosylated.

21. A glycoengineered, recombinant antibody according to claim 11 , wherein said altered activity comprises altered expression of at least one glycoprotein-modifying glycosyltransferase.

22. A glycoengineered, recombinant antibody according to claim 19 , wherein said altered activity comprises altered expression of at least one glycoprotein-modifying glycosyltransferase.

23. A glycoengineered, recombinant antibody according to claim 20 , wherein at least 45% of the oligosaccharides in the Fc region are complex structures.

24. A glycoengineered, recombinant antibody according to claim 20 , wherein said glycoengineered, recombinant antibody exhibits at least an 80% increase in maximal ADCC activity compared to the same antibody produced by the same host cell under identical culture and purification conditions, but which has not been glycoengineered.

25. A glycoengineered, recombinant antibody according to claim 11 , wherein said at least one glycoprotein-modifying glycosyltransferase is GnTIII or ManII.

26. A glycoengineered, recombinant antibody according to claim 1 , wherein said IgG Fc region containing N-linked oligosaccharides comprises an entire IgG Fc region.

27. A glycoengineered, recombinant antibody according to claim 1 , wherein said IgG Fc region containing N-linked oligosaccharides comprises an IgG fragment.

28. A glycoengineered, recombinant antibody according to claim 27 , wherein said IgG fragment comprises a CH2 domain.

29. A glycoengineered, recombinant antibody according to claim 1 , wherein said antibody has increased Fc receptor binding affinity as a result of said increased ratio of GlcNAc residues to fucose residues.