Transcription Factors in Mature B Cells During Aging

The purpose of this chapter is to give an overview of the age-related changes in the expression and function of the major transcription factors regulating mature B cells. We also summarize our recent work and show that the age-related defects in Ig class switch are directly related to the decrease in the transcription factor E47 which controls the expression of activation-induced cytidine deaminase (AID), the enzyme needed for class-switch recombination (CSR) and somatic hypermutation (SHM). The age-associated effects on the expression and function of the transcription factors NF-kB and Pax-5 are also described. Blimp-1 seems not to be modified by aging, and only one report has shown age effects on Bach2. For other transcription factors relevant for mature B cell functions, such as IRF4, Notch2, and HoxC4, no effects of aging have been reported so far. The defects presented herein for aged B cells should allow the discovery of mechanisms to improve humoral immune responses in both humans and mice in the near future