研究報告Original PaperRegulatory T (Treg) cells can suppress effector T cells, but the mechanism underlying its suppression function is not comprehended. Here we examine the inhibiting co-stimulating molecule CTLA4 and cytokines secreted by Treg cells, and explore the immunology mechanism of T regulatory cells acting on effector T cells in co-cultured system (CCS) and separating-cultured system (SCS). Compared with effector T cells, Treg cells expressed higher level CTLA4 and secreted much more IL-10 and TGF-β_1 (P<0.01). The inhibitory capacity of Treg cells co-cultured with effector T cells is much stronger than that in separating cultured group (P<0.01). Moreover, the inhibiting rate of Treg cells exerting on effector T cells through secreting IL-10 was more powerful than that through secreting TGF-β_1 (P<0.01). Both cell-to-cell contact and cytokines secretion mechanisms are involved in CD4^+CD25^+ Treg cells operating function. However, the former is more important. Interestingly, we for the first time point found that IL-10 make more powerful role than TGF-β_1 in the cytokines secretion mechanism
