Alterations in splenic architecture and the localization of anti-double-stranded DNA B cells in aged mice

Aging is characterized by a decline in humoral immunity and a concommitant increased incidence of anti-DNA and other autoantibodies. To define how the regulation of autoreactive B cells is altered with age, we have used BALB/c mice with an Ig heavy H chain transgene to track the fate of anti-double-stranded (ds) DNA B cells in vivo. In young adult mice, anti-dsDNA B cells are developmentally arrested and excluded from the splenic B cell follicle, whereas in most aged mice they are mature and localize within the B cell follicle. Furthermore, we have detailed global changes in lymphoid architecture that accompany aging: CD4⁺ T cells are found not only in the periarteriolar lymphoid sheath, but also in the B cell follicles, Strikingly, these disruptions are similar to those that precede serum anti-dsDNA antibody expression in autoimmune MRL-lpr/lpr mice.