Antiviral activity of tunicamycin on herpes simplex virus

Tunicamycin (0.5 μg/ml) significantly lowers (2 to 3 log₁₀) the infectious yield of herpes simplex virus type 1 grown in chicken embryo fibroblasts and in BSC1 cells. Although virus particles are formed and the synthesis of the viral deoxyribonucleic acid is only partially affected by the antibiotic, the glycosylation of herpesvirus glycopeptides is almost completely inhibited. The morphology of virus particles made in the presence of tunicamycin is similar to that of intact virus particles, as demonstrated by electron microscopy. This suggests that the absence of the carbohydrate side-chain from the viral glycopeptides does not affect the overall integrity of the virion but decreases very significantly the infectivity of these particles.