Cutting edge: Oral type I IFN-τ promotes a Th2 bias and enhances suppression of autoimmune encephalomyelitis by oral glatiramer acetate

IFN-τ, a novel type I IFN that possesses immunomodulatory properties, lacks toxicity normally associated with other type I IFNs. We examined the effects of oral IFN-τ alone and in combination with oral glatiramer acetate in experimental allergic encephalomyelitis (EAE). By comparison of oral administration of IFN-α, -β, and -τ to myelin basic protein-specific TCR-transgenic mice, we demonstrate these type I IFNs promote secretion of the Th2 cytokine IL-10 with similar efficiency. Whereas IFN-α and -β induced IFN-γ secretion, a Th1 cytokine, IFN-τ did not. Oral IFN-τ alone suppressed EAE. When suboptimal doses were administered orally in combination to wild-type mice, IFN-τ and glatiramer acetate had a synergistic beneficial effect in suppression of EAE. This combination was associated with TGF-β secretion and enhanced IL-10 production. Thus, IFN-τ is a potential candidate for use as a single agent or in combination therapy for multiple sclerosis.