Patent ID: 8809051

Claim:
An antibody-producing B cell isolated from a transgenic mouse immunized with an antigen, wherein the genome of said transgenic mouse comprises: (i) a fragment of human chromosome 14 from the five most proximal V H gene segments, continuing through the D segment genes, the J segment genes and the constant region genes through Cδ of the human immunoglobulin heavy chain locus, wherein said fragment does not contain a Cγ gene, and wherein said fragment is operably linked to a human Cγ gene selected from the group consisting of: a human Cγ1 gene, a human Cγ3 gene, and a human Cγ4 gene; and (ii) a fragment of human chromosome 2 comprising human V κ , human J κ and human C κ gene segments of an immunoglobulin kappa light chain locus; wherein said transgenic mouse produces fully human antibodies having IgG1, IgG3, or IgG4 heavy chains, respectively, specific for a desired antigen when immunized with said desired antigen.