Oral feeding of interferon τ can prevent the acute and chronic relapsing forms of experimental allergic encephalomyelitis

Abstract

IFNτ is a member of the type I IFN family but unlike IFNα and IFNβ, IFNτ lacks toxicity at high concentrations. Recently, ovine IFNτ was shown to prevent acute induction and superantigen reactivation of experimental allergic encephalomyelitis (EAE), an animal model for multiple sclerosis (MS). In this report, we examined the ability of IFNτ when administered by oral feeding to block development of EAE. Oral feeding of IFNτ prevented paralysis in the acute form of EAE in NZW mice and chronic-relapsing EAE in SJL/J mice. In addition, oral feeding of IFNτ at 105 U/dose was as effective as intraperitoneal (i.p.) injection in preventing chronic-relapsing EAE, and both forms of IFNτ administration resulted in IL10 production. Histological examination revealed no inflammatory lymphocytic infiltration to the CNS in IFNτ treated animals as compared to controls. Prolonged treatment of IFNτ was shown to be necessary for chronic-relapsing EAE since removal of IFNτ treatment by either oral feeding or i.p. injection resulted in onset of disease. Lastly, sera from SJL/J mice which received prolonged IFNτ treatment by oral feeding exhibited little to no development of anti-IFNτ antibodies. Thus, oral feeding of ovine IFNτ may be a successful form of IFNτ administration for treatment of autoimmune diseases such as MS and may circumvent potentially debilitative antibody responses.