Patent ID: 7960517

Claim:
A method of altering the amino acid sequence of a complementarity determining region (CDR) of an antibody, comprising: a) identifying a variation tolerant position in a CDR of a parent antibody by comparing the amino acid sequence of said parent antibody to the amino acid sequence of a related antibody that is obtained from the same animal as said parent antibody, wherein said parent antibody and said related antibody: i. bind to the same antigen; ii. have H3 CDRs that are identical in length and identical in sequence except for 0, 1 or 2 amino acid substitutions relative to one another; iii. have L3 CDRs that are identical in length and identical in sequence except for 0, 1 or 2 amino acid substitutions relative to one another; and iv. have at least one amino acid substitution in a CDR relative to one another; and b) substituting the amino acid present at said variation tolerant position in said CDR with a different amino acid to produce an altered antibody that binds the same antigen as the parent antibody.