Patent ID: 7576258

Claim:
A method for generating a human sequence antibody or fragment thereof that binds to a predetermined antigen, the method comprising: isolating antibody V region nucleic acid sequences from a transgenic mouse, the transgenic mouse comprising two human immunoglobulin loci, wherein one of the human immunoglobulin loci is a human heavy chain locus and the other human immunoglobulin loci is a human light chain locus; wherein the human heavy chain locus is carried by transchromosome SC20 and the human light chain locus is carried by a transgene integrated into the genome of said mouse, and wherein an endogenous mouse heavy chain locus and at least one endogenous mouse light chain locus are inactivated, the transgenic mouse having been immunized with a predetermined antigen; cloning the isolated V regions into a vector to generate an expression library; and expressing the library to identifiy V region nucleic acid sequences that encode a human antibody sequence or fragment thereof that binds to the predetermined antigen.