Resurfacing of rodent antibodies

A method for producing a humanized rodent antibody or fragment thereof by resurfacing, said method consisting essentially of:

• (a) generating position alignments from relative accessibility distributions from x-ray crystallographic structures of a pool of rodent and human antibody heavy and light chain variable regions to give a set of heavy and light chain variable region framework surface exposed positions wherein the alignment positions for all rodent and human variable regions are at least about 98% identical;
• (b) defining for a rodent antibody or fragment thereof a set of heavy and light chain variable region framework surface exposed amino acid residues using said set of heavy and light chain variable region framework surface exposed positions generated in said step (a);
• (c) identifying from human antibody amino acid sequences a set of heavy and light chain variable region framework surface exposed amino acid residues that is most closely identical to said set of rodent surface exposed amino acid residues defined in said step (b);
• (d) substituting, in the variable region framework amino acid sequence of said rodent antibody or fragment thereof, said set of heavy and light chain variable region framework surface exposed amino acid residues defined in said step (b) with said set of heavy and light chain variable region framework surface exposed amino acid residues identified in said step (c);
• (e) constructing three-dimensional models of said variable region of said rodent antibody or fragment thereof and of said variable region of said rodent antibody or fragment thereof resulting from the substituting specified in said step (d);
• (f) comparing said three-dimensional models constructed in said step (e), and identifying any amino acid residues from said sets identified in said steps (b) or (c), that are within 5 .ANG.ngstroms of any atom of any residue of the complementarity determining regions of said rodent antibody or fragment thereof;
• (g) changing any residues identified in said step (f) from the human to the original rodent amino acid residue to thereby define a humanizing set of surface exposed amino acid residues;
• (h) replacing the set of rodent antibody variable region framework surface exposed amino acid residues defined in said step (b) with the humanizing set of variable region framework surface exposed amino acid residues defined in said step (g);
• and
• (i) producing said humanized rodent antibody or fragment thereof having binding specificity.