Abstract
Investigation of the effects of 4,5,6-trichloro-1-D-ribofuranosyl benzimidazole and 2-mercapto-1-(-4-pyridethyl) benzimidazole on cellular RNA synthesis and virus multiplication showed that both compounds, like actinomycin, preferentially inhibited DNA-directed RNA synthesis. All three compounds inhibited interferon production initiated by several different viruses, and actinomycin inhibited interferon production almost as rapidly as it inhibited DNA-directed RNA synthesis. It was concluded that the compounds inhibited interferon production because of their primary action on DNA-directed RNA synthesis. Interferon production initiated by Chikungunya virus and ultraviolet-inactivated Newcastle disease virus was unaffected by addition of the inhibitors after interferon production had begun, while interferon production initiated by ultraviolet-inactivated influenza virus remained partially susceptible to the effect of the inhibitors.