Foxp3+ Treg have thus been used to control adverse Th17 responses during autoimmune disease 7–9. Although the co-transfer of Treg can abrogate effector T-cell-mediated systemic autoimmune disease and inhibit IFN-γ production, it can enhance IL-17 production 7. In an autoimmune
gastritis BEZ235 model induced with Th1, Th2, or Th17 effector cells, Th17 cells were less susceptible to inhibition by Treg compared with Th1 or Th2 cells 8. The co-culture of Treg and effector T cells derived from a diseased central nervous system also demonstrated that IFN-γ production, but not IL-17 production, was inhibited by Treg 9. Moreover, the conversion of Treg into Th17 cells
has been reported both in mice and in humans 10, 11. Therefore, Foxp3+ Treg may be limited in their ability to control Proteases inhibitor Th17-mediated inflammatory diseases. Endogenous uveitis is a chronic inflammatory eye disease that frequently results in blindness 12. Experimental autoimmune uveitis (EAU) is a disease model of human endogenous uveitis and can be induced through immunization with retinal proteins, including the interphotoreceptor retinoid-binding protein (IRBP) 13. EAU is a CD4+ T-cell-mediated disease, and Th1 responses were suggested to be essential factors in its pathogenesis. Disease susceptibility paralleled Th1 responsiveness among the different mouse or rat strains 14. Recently, Th17 cells have been implicated in disease progression
of autoimmune eye diseases of human and animal models, including uveitis and scleritis. Th17 cells among peripheral blood mononuclear cells were increased in active uveitis and scleritis patients and anti-IL-17-blocking antibody treatment mitigated EAU in animal models 15. IL-17 and IFN-γ were suggested to have distinct pathogenic roles in different animal models of experimental uveitis 16, 17, whereas another study reported a preferential pathogenic role for IL-17 Rho and a regulatory role for IFN-γ 15. NKT cells have a wide spectrum of immunomodulatory activities 18, 19. We have previously demonstrated that NKT cells prolonged skin graft survival across minor histocompatibility mismatch combinations 20. NKT cells have also demonstrated anti-viral and anti-tumor activity and contribute to the regulation of autoimmune disease 18, 19. The regulatory capabilities of NKT cells in autoimmune disease, including recently defined Th17-mediated diseases, have been reported in both spontaneous and induced disease models 21–25. Activated NKT cells can suppress the development of autoimmune diabetes 21, 22 and encephalitis 23, 24, and co-transferred DX5+ NKT cells suppressed disease in a chronic colitis model 25.