Does activation-induced deaminase initiate antibody diversification by DNA deamination

Abstract

Activation-induced deaminase (AID) is expressed only in germinal center B cells. There, it is required for somatic hypermutation, gene conversion and class switch recombination of antibody variable region segments, three processes that diversify antibodies during immune responses. Although AID has homology to RNA-editing enzymes, three recent reports suggest it could initiate the diversification processes by deaminating cytidine residues within the antibody genes themselves.