Studies on Viral Inhibitors of Biological Origin. I. Inhibition of Viral Replication by Protein-Like Constituents of Bacteria. ∗

Abstract

Summary

Viral inhibitory factors were isolated from several different bacterial species including representatives of both gram negative and positive groups. Two of the factors were found to prevent viral cytopathogenicity even when added as late as 18 hours after viral inoculation. Trypsin sensitivity indicates that these inhibitors are probably proteins. Evidence is presented that viral inhibition appears to occur during the intra-cellular stages of viral replication. Each factor has a sharply specific spectrum of antiviral activity. This specificity of action may reflect blocking of cellular metabolic pathways necessary only for the replication of the virus affected.