Two mechanisms account for generation of the human antibody repertoire; V (D) J
recombination during the early stages of B‐cell development in the bone marrow and
somatic mutation of immunoglobulin genes in mature B cells responding to antigen in the
periphery. V (D) J recombination produces diversity by random joining of gene segments
and somatic mutation by introducing random point mutations. Both are required to attain the
degree of antigen receptor diversification that is necessary for immune protection: defects in …