Antiviral activity of the prostanoid clavulone II against vesicular stomatitis virus

Prostaglandins of the A series exhibit the most pronounced antiviral activity in cells infected with RNA or DNA viruses as compared to other prostaglandins. Clavulone is a prostaglandin A analog found in the soft coral Clavularia viridis. Using vesicular stomatitis virus in mouse L929 fibroblasts as a model system, 50% inhibition of viral yield was seen at a concentration of 1-1.5 microM, whereas 50% cytotoxicity required 50-70 times higher inhibitor concentrations. For a further elucidation of the antiviral mechanism a temperature-sensitive mutant, tsG 41, was used, which is replication-negative at the restrictive temperature. Results obtained with this mutant suggest that inhibition of VSV replication occurs at the level of transcription.