Error-Prone Candidates Vie for Somatic Mutation

Antibodies play a major role in the resistance of higher organisms to disease. This is made possible because mice, humans, and other species have evolved three unusual molecular mechanisms that allow the generation of an enormously diverse repertoire of antibodies from a relatively small amount of genetic material. First, each antibody-forming B cell assembles different combinations of variable (V), diversity (D), and joining (J) minigenes to create an antibody with a unique antigen-binding site. Second, to generate the high-affinity antibodies that are required for survival, B cells target many point mutations to the V(D)J regions of the H and VJ region of the L chain immunoglobulin (Ig) genes. Those B cells that are making higher affinity antibodies are selected for further growth and differentiation, resulting in the affinity maturation of the antibody response. Third, B cells rearrange the H...