Objective:To check the effect of immunosuppressants as adjuvants for DNA vaccine to prevent autoimmune disease.Methotis:Three immunosuppressants,Cyclosporin A(CsA),Tacrolimus(FK506)and Mycophenolate Mofetil(MMF)Were combined with DNA vaccine of Multiple Sclerosis(MS)and injected intramuscuarly.The splenocytes of immunized mice were checked for regulatory T cells(Treg),T cell proliferation and maturation of dendritic cells(Dcs)as well as release of intereleukin 10(IL-10).The immunized mice were induced as EAE animal model to check the preventive effect of FK506 as adjuvant.Results:More Treg cells Were induced in the mice immunized with FK506 and DNA vaccine and also T cell proliferation Was suppressed.DCs maturation Was blocked and high level of IL-10 in DCs Was induced in mice treated with FK506 and DNA vaccine.The clinic scores of EAE were significantly decreased in mice treated with FK506 and DNA vaccine compared with other control groups.Conclusion:FK506 as adjuvant of DNA vaccine can stimulate Treg cells and immune tolerance,then prevent from the autoimmune disease.