Effect of chloroquine on the growth of animal viruses.

Abstract

The effect of chloroquine diphosphate on the growth of polio type 1, influenza, Newcastle disease, Sendai, vesicular stomatitis and vaccinia viruses was studied. Host dependency of the antiviral effect of chloroquine on Newcastle disease and Sendai viruses was shown using HeLa S 3 cells and primary chick embryo fibroblast cells. The antiviral effect of chloroquine was extensively studied in chick embryo cells infected with vesicular stomatitis virus. Chloroquine at a concentration of 12.5 μg per ml markedly reduced the virus yield. The drug did not affect the adsorption of vesicular stomatitis virus to chick embryo cells. No evidence for inhibition of the virus uncoating process by the drug was obtained in our present system. The addition of chloroquine at various times after the latent period induced immediate inhibition of the synthesis of progeny virus. Chloroquine inhibited selectively the synthesis of viral RNA without affecting that of cellular RNA or the synthesis of viral antigens.