NKT Cells Stimulated by Long Fatty Acyl Chain Sulfatides Significantly Reduces the Incidence of Type 1 Diabetes in Nonobese Diabetic Mice
Figure 4
Analyses of NOD T cell cytokine secretion responses induced by sulfatides.
(A, B) C16:0 and C24:0 sulfatide stimulate different CD4+ T cell cytokine secretion profiles. NOD spleen CD4+ T cells were co-cultured for 72 h with mitomycin treated CD4– cells at a CD4+:CD4– ratio of 100∶1 in the presence of control vehicle or sulfatide (C16:0 or C24:0, 50 mg/ml), as described in Fig. 3A. The concentration of IFN-g (A) and IL-10 (B) secreted into cell supernatants were analyzed by ELISA. IL-2 and IL-4 were not detected in these supernatants. Data shown were obtained from one of three representative and reproducible experiments. (C, D) Treatment with sulfatide inhibits the induced anti-islet diabetogenic T cell cytokine responses. Female NOD mice (4 week-old, 4 mice/group) were injected i.p. with sulfatide (20 mg/mouse) or vehicle/PBS. One week later, the treated mice were immunized with 100 mg of either the insulin p9–23, GAD206-220, GAD524-543 or hsp277 peptide. Ten days following antigenic challenge, PLN lymphocytes were assayed for their proliferative ([3H]-thymidine incorporation) and cytokine (IFN-g, IL-4) secretion responses (Elispot assay). The average frequencies of IFN-γ (C) or IL-4 (D) secreting cells reactive to different islet antigens are shown. In comparison to control vehicle values, statistically significant reductions in the frequencies of cytokine-secreting islet antigen-reactive T cells were found for the insulin and GAD peptides but not Hsp peptide, as follows. Insulin 9–23 (P = 0.0001 for IFN-g, P = 0.0078 for IL-4); GAD 206-220 (P = 0.012 for IFN-g, P = 0.0018 for IL-4); GAD 524-543 (P<0.0001 for IFN-g, P = 0.0328 for IL-4); and Hsp 277 (Not significant, P = 0.0542 for IFN-g; Not significant, P = 0.0952 for IL-4).