A Comparison of the Efficacy of Endogenous, Exogenous, and Combined Endogenous-Exogenous Interferon in the Treatment of Mice Infected with Encephalomyocarditis Virus

The efficacy of endogenous, exogenous, and combined endogenous-exogenous interferon was compared in the treatment of mice preinfected with 40–80 LD50 of EMC virus. The different interferon inducers, Newcastle Disease virus, statolon, and poly (I) poly (C) proved equally effective in increasing the survival of viral infected mice. Daily reinoculation of an inducer afforded no significant added protection. Administration of potent interferon preparations proved more effective than any of the interferon inducers in 3 experiments and equally effective in a fourth experiment. In 2 experiments no significant difference was observed between the therapeutic efficacy of combined endogenous-exogenous interferon and exogenous interferon alone, whereas in a third experiment the combined treatment proved more effective. A combined interferon treatment initiated 18 or 24 hr after inoculation of 2.5 or 8 LD50 of EMC virus still afforded a significant degree of protection.