Patent ID: 7087409

Claim:
A method of producing a humanized mouse monoclonal antibody which consists of the steps: (a) constructing a first human antibody heavy or light chain library consisting of antibody heavy chains or antibody light chains in which each chain in the first human antibody light or heavy chain library has three complementarity determining region (CDR) loops in which the complementarity determining region three (CDR3) loop in each light or heavy chain has the amino acid sequence of a corresponding mouse antibody heavy or light chain CDR3 loop and is flanked by unaltered human framework residues; (b) constructing a second human antibody heavy or light chain library consisting of antibody heavy chains or antibody light chains, in which each chain in the second human antibody heavy or light chain library has three complementarity determining region (CDR) loops in which the complementarity determining region three (CDR3) loop in each light or heavy chain has the amino acid sequence of a corresponding mouse antibody heavy or light chain CDR3 loop and is flanked by unaltered human framework residues; wherein the chains of said second human antibody heavy or light chain library are the complementary heavy or light chain of said first human antibody heavy or light chain library chains, such that one library is a light chain library and the other library is a heavy chain library; (c) creating a library of heavy and light chain pairs by combining chains from said first human antibody heavy or light chain library of step (a) with a complementary chain from an antibody which binds a preselected antigen forming a library of heavy and light chain pairs; (d) isolating antigen binding chains of step (a) by selecting from the library of step (c), a heavy and light chain pair which binds to said preselected antigen, isolating from the antigen binding heavy and light chain pair, the antigen binding chains of step (a); (e) creating a humanized pair library by combining isolated antigen binding chains of step (d), with chains of said library of step (b), so that a first isolated chain of step (d), together with a complementary second chain in said library of step (b) combine to form a heavy and light chain humanized pair library; (f) selecting from the humanized pair library of step (e) a humanized heavy and light chain pair that binds to said preselected antigen; and (g) combining two of said selected humanized heavy and light chain pair of step (f) to form a whole antibody; wherein said humanized mouse monoclonal antibody binds the same antigen as the mouse monoclonal antibody.