[摘要]：CD4(+)CD25(+)Foxp3(+) Tregs play a major role in prevention of autoimmune diseases The suppressive effect of Tregs on effector T cells (Teffs), the cells that can mediate autoimmunity, has been extensively studied However, the m vivo impact of Teff activation on Tregs during autoimmunity has not been explored In this study, we have shown that CD4(+) Teff activation strongly boosts the expansion and suppressive activity of Tregs This helper function of CD4+ T cells, which we believe to be novel, was observed in the pancreas and draining lymph nodes in mouse recipients of islet-specific Teffs and Tregs Its physiological impact was assessed in autoimmune diabetes When islet-specific Teffs were transferred alone, they induced diabetes Paradoxically, when the same Teffs were cotransferred with islet-specific Tregs, they induced disease protection by boosting Treg expansion and suppressive function RNA microarray analyses suggested that TNF family members were involved in the Teff-mediated Treg boost In vivo experiments showed that this Treg boost was partially dependent on TNF but not on IL-2 This feedback regulatory loop between Teffs and Tregs may be critical to preventing or limiting the development of autoimmune diseases
