Because IL-1β is induced via the innate immunity mediated by various TLRs and because the downstream IL-1 signals mediated via IL-1R also play an important role in the host defense [1,4], we have investigated the role of IL-1β signals in the development of TMEV-induced demyelinating disease by assessing the effects of IL-1β administration and using IL-1R-deficient mice. The gene discussed is IL1A; the disease is demyelinating disease.