Objective To investigate the role of T cell and its subsets in the induction of insulitis and type 1 diabetes mellitus(T1DM)in BALB/c mice.Methods Autoimmune diabetes mellitus was developed by intraperitoneal injection of 40 mg/kg streptozotocin(STZ)daily for 5 consecutive days in BALB/c mice as sources of donor cells.Spleen cells from diabetic mice were then cultured for 7 days in the stimulation of interleukin-2(IL-2)to harvest diabetogenic T cells,which were subsequently transferred into normal BALB/c mice recipients.MTT,ELISA,and HE staining were used to analyze the lymphocyte proliferation,cytokine(IL-2,interferon-γ,IL-4,and IL-10)levels,and pathological changes in pancreatic islets.Results As few as 3×106 diabetogenic T cells successfully induced diabetes mellitus in recipients pretreated with STZ twice,whereas transfer of equal amount of normal splenocytes,T cell-depleted diabetogenic splenocytes,or diabetogenic CD4+ T cells alone in recipients receiving STZ twice pretreatment was proved not to induce diabetes mellitus either.A markedly increased lymphocyte proliferation,high levels of interferon-γ and IL-2 in the supernatants of diabetogenic T cells were observed.In addition,a markedly enhanced lymphocyte proliferation,a high level of interferon-γ secretion in serum,and numerous lymphocytes infiltration in pancreatic islets were detected in the diabetic mice induced by diabetogenic T cells transfer.Conclusions A novel T1DM murine model is established in STZ-pretreated BALB/c mice by adoptive transfer of diabetogenic T cells.CD4+ T cells with interferon-γ may promote the onset of diabetes mellitus.
Xiao-lei Zou Zeng-yu Zhao Yun-yang Wang Zhi-qiang Su Ming Xiang
Administration of autoantigen can be of value for prevention of autoimmune diabetes and it has been speculated that the control point of dendritic cells(DC)for the induction of peripheral toler- ance may be highly relevant.We examined the properties of DC associated with immune suppression in NOD mice by insulin injection subcutaneously and their ability to suppress diabetes transfer by diabeto- genic effector cells in secondary NOD-SCID recipients.Our data showed that the surface expressions of MHCⅡand CD86 on NOD-derived DC were increased after insulin treatment compared with those on PBS controlled mice.The dendritic cells with a mature phenotype and increased MLR stimulation adop- tively transferred immune tolerogenic effects on secondary NOD-SCID mice,which were associated with significantly greater IL-10,TGF-beta production and CD4^+ CD25^+ T differentiation from splenocytes compared with NOD-SCID control recipients.Moreover,treatment with DC remarkably decreased the incidence of diabetes in secondary recipients.These results suggest that a subtype of DC generated by insulin subcutaneous treated NOD mice confers potential protection against diabetes through polarizing the immune response towards a Th2 regulatory pathway.
MING XIANG XIAO LEI ZOU JING XU YAO YAO JIN FANG ZHANG
