IFN-τ Suppresses Both the Autoreactive Humoral and Cellular Immune Responses and Induces Stable Remission in Mice with Chronic Experimental Allergic Encephalomyelitis

We have previously shown that interferon-τ (IFN-τ) pretreatment inhibits the development of both acute and chronic mouse experimental allergic encephalomyelitis (EAE), an animal model for the human demyelinating disease multiple sclerosis (MS). IFN-τ is a type I IFN that has pregnancy recognition hormone activity in ruminants. Here, we show that IFN-τ induced remission in SJL/J mice that had ongoing chronic active EAE disease and protected mice against secondary relapses. IFN-τ treatment reversed lymphocyte infiltration and microglial activation in the central nervous system. Mice that were treated with IFN-τ had lower levels of anti-MBP antibodies than untreated mice in both chronic and acute forms of EAE. MBP induced proliferation in B cells from EAE mice, but treatment with IFN-τ eitherin vivoorin vitroblocked activation. Furthermore, IFN-τ inhibited MBP activation of T cells from EAE mice. Thus, IFN-τ inhibits the humoral arm as well as the cellular arm of the autoimmune disease EAE. The data presented here show that IFN-τ inhibits both B cell and T cell responses in EAE as well as active, chronic EAE, and this may help explain the effectiveness of type I IFNs in treatment of MS.