Inhibition of Th17 Cells Regulates Autoimmune Diabetes in NOD Mice

CD4-positive T-cells that secrete interleukin (IL)-17, has been implicated in autoimmune diseases, including multiple sclerosis and lupus. Therapeutic agents that target the Th17 effector molecule IL-17 or directly inhibit the Th17 population (IL-25) have shown promise in animal models of autoimmunity. The role of Th17 cells in type 1 diabetes has been less clear. The effect of neutralizing anti–IL-17 and recombinant IL-25 on the develop-ment of diabetes in NOD mice, a model of spontaneous autoim-mune diabetes, was investigated in this study. RESEARCH DESIGN AND METHODS AND RESULTS— Although treatment with either anti–IL-17 or IL-25 had no effect on diabetes development in young (5 weeks) NOD mice, either intervention prevented diabetes when treatment was started at 10 weeks of age (P 0.001). Insulitis scoring and immunofluo-rescence staining revealed that both anti–IL-17 and IL-25 signif