Protection Against Herpes Virus and Encephalomyocarditis Virus Encephalitis with a Double-Stranded RNA Inducer of Interferon

Abstract

Summary

The interferon sensitivities of intracerebrally administered HSV (VR₃ strain) and EMCV (r+ strain) were determined in mice with a potent inducer of circulating interferon, polyinosinic·polycytidylic ribonucleic acid (In·Cn). With the treatment as described, delay in mortality occurred at most challenge doses of HSV and EMCV. Significant delay in mortality and increased survival was obtained with 1000 and 100 TCID₅₀ of EMCV, whereas, significant protection was achieved for only 1 TCID₅₀ of HSV with mortality decreasing to about 12–20% as compared to 52–58% in the controls. The data show that sufficient interferon can be induced in the mouse with In·Cn to significantly alter intracerebral infection with HSV and EMCV. The protective effect of In·Cn against intracerebral infection of mice with HSV and EMCV was equal only when the challenge dose of each was sufficiently low. The protective effect against HSV was lost with increasing virus doses of virus whereas the protective effect against EMCV decreased only slightly with increasing virus dose.