A Major Role for Bim in Regulatory T Cell Homeostasis

摘要: We have previously shown that regulatory T cells (Treg) accumulate dramatically in aged animals and negatively impact the ability to control persistent infection. However, mechanisms underlying age-dependent accrual of Treg remain unclear. In this study, we show accumulation with age is progressive likely not result increased thymic output, peripheral proliferation, or from enhanced conversion. Instead, found mice are more resistant apoptosis than young mice. Although had expression functional IL-7Rα, IL-7R signaling was required for maintenance vivo. Notably, exhibit decreased proapoptotic molecule Bim compared Furthermore, absence Bim, rapidly, accounting >25% CD4 + cell compartment by 6 mo age. Additionally, Bim-deficient occurred after left transitional recent emigrant compartment. Mechanistically, IL-2 drives preferential proliferation lo Treg. Collectively, our data suggest chronic stimulation leads expansion having low which favors their survival hosts.