title: Curiouser and curiouser: the role(s) of AID expression in self-tolerance.
abstract: Aicda is crucial for antibody diversification by mediating Ig class-switch recombination, V(D)J hypermutation (SHM) and, in some species, gene conversion. Recently, evidence has accumulated to show that Aicda is expressed during B-cell development and that this expression in some unknown way, mediates tolerance in immature and transitional B cells. In this issue of the European Journal of Immunology, Umiker et al. [Eur. J. Immunol. 2014. 44: 3093-3108] show that enforced expression of Aicda during early B-cell development is associated with self-tolerance. Curiously, constitutive Aicda expression that begins early in B cells suppresses the generation of autoreactive IgM but promotes the expression of self-reactive IgG. In contrast, when Aicda is activated later in B-cell development, self-reactive IgM is abundant but IgG is not. These observations suggest pathways for self-tolerance that have been little explored.
authors.affiliation: Department of Immunology and Human Vaccine Institute, Duke University, Durham, NC, USA.
authors.forename: Garnett
authors.initials: G
authors.lastname: Kelsoe
mesh_terms: D000818:Animals; D000974:Antibodies, Antinuclear / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D003564:Cytidine Deaminase / Q000276:immunology*; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D000098830:AICDA (Activation-Induced Cytidine Deaminase)
chemical_list: D000974:Antibodies, Antinuclear; D000098830:AICDA (Activation-Induced Cytidine Deaminase); D003564:Cytidine Deaminase
keywords: Antibodies; Autoimmunity; B cell development; B cells; Immunopathology