Reduced Incidence and Severity of Antigen-induced Autoimmune Diseases in Mice Lacking Interferon

Interferon regulatory factor-1 (IRF-1) is a transcription factor that regulates interferon-induced genes and type I interferons. Recently, studies of IRF-1-deficient mice have revealed that IRF-1 regulates the induction of molecules that play important roles in inflammation, such as inducible nitric oxide synthase (iNOS) and interleukin-1 b -converting enzyme (ICE). To study the role of IRF-1 in autoimmunity, we investigated type II collagen-induced arthritis (CIA), and experimental allergic encephalomyelitis (EAE), in mice lacking IRF-1. The incidence and severity of CIA were significantly decreased in IRF-1 2 / 2 mice compared with IRF-1 1 / 2 mice, as was the production of interferon (IFN)g in lymph node cells. Both IRF-1 1 / 2 and IRF-1 2 / 2