Abstract:Objective:To investigate the effect and mechanism of different macrophage subtypes on the induction process of regulatory T cells(Tregs). Methods: The cells was divided into the normal group(noM group),the primary macrophages effect group (M0 group),the M1 effect group (M1 group) and the M2 effect group (M2 group) according to different induction conditions. Foxp3 expression of Tregs and proliferation of effector T cells in co-culture and Transwell experiments were tested by flow cytometry. Serum of ALT was analyzed by automatic biochemistry analyzer and the injury of liver in ischemia reperfusion(IR) was detected by H&E staining. Results: Compared with the noM group, the expression of Foxp3 was reduced in the M0 group and the M2 group(both P < 0.01), while no significant difference was observed in the M1 group. What’s more,the suppressive ability of Tregs from the M0 and M2 group were less than those from the M0 and M2 group both in vitro and in vivo (both P < 0.01). Mechanism study proved that the regulatory effect of macrophage to Tregs was depended on cell-cell contact(P < 0.05). Conclusion: Our study suggests that peritoneal macrophages play an important role in regulating the induction of Tregs in vitro,which present key therapeutic potential in maintaining immune balance.