Abstract
IFN
τ is a member of the type I IFN family but unlike IFN
α and IFN
β, IFN
τ lacks toxicity at high concentrations. Recently, ovine IFN
τ 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 IFN
τ when administered by oral feeding to block development of EAE. Oral feeding of IFN
τ prevented paralysis in the acute form of EAE in NZW mice and chronic-relapsing EAE in SJL/J mice. In addition, oral feeding of IFN
τ at 10
5 U/dose was as effective as intraperitoneal (i.p.) injection in preventing chronic-relapsing EAE, and both forms of IFN
τ administration resulted in IL10 production. Histological examination revealed no inflammatory lymphocytic infiltration to the CNS in IFN
τ treated animals as compared to controls. Prolonged treatment of IFN
τ was shown to be necessary for chronic-relapsing EAE since removal of IFN
τ treatment by either oral feeding or i.p. injection resulted in onset of disease. Lastly, sera from SJL/J mice which received prolonged IFN
τ treatment by oral feeding exhibited little to no development of anti-IFN
τ antibodies. Thus, oral feeding of ovine IFN
τ may be a successful form of IFN
τ administration for treatment of autoimmune diseases such as MS and may circumvent potentially debilitative antibody responses.
