HUMANIZATION OF MOUSE ANTI-HUMAN IL-2 RECEPTOR ANTIBODY B-B10

Mouse monoclonal anti-human IL-2 receptor antibody (B-B10) inhibits IL -2-dependent human T-cell proliferation. It has been used in clinical trials in the transplantation field and promising results are being ac cumulated. Mouse B-B10 antibody was humanized by grafting all CDRs and some framework amino acid residues onto human antibodies, KAS for V-H and PAY for V-k. Nine humanized B-B10s with differently grafted frame work residues were constructed and assessed for their biological activ ities. One of these humanized B-B10, M5, showed nearly the same activi ty as the mouse B-B10. The 49th residue of V-k was demonstrated to pla y a crucial role in the antigen-antibody interaction by 3-D structure analysis with a computer modeling system.