Effect of ara-T on the replication of herpes simplex virus, varicella-zoster virus and cytomegalovirus.

The thymidine analogue, 1-beta-arabinofuranosylthymine (ara-T), has previously been found to selectively inhibit herpes simplex virus (HSV) replication. At a relatively non-toxic concentration (50 microgram/ml), ara-T reduced HSV yields by a factor of 10,000-100,000. Ara-T was also effective in inhibiting the replication of variecella-zoster virus (VZV) in vitro in human embryo fibroblasts, completely preventing VZV-specific cytopathic effects (CPE). Ara-T reduced the cell-free virus and plaque-forming cell (PFC) yields of VZV as well as of the simian varicella-like virus, Delta herpesvirus. In contrast to HSV and VZV, cytomegalovirus (CMV) replication was relatively resistant to ara-T. Neither CPE nor the incorporation of 3H-thymidine into acid-insoluble material in CMV-infected cells was markedly affected. Interpretation of these results with regard to virus-induced deoxypyrimidine kinase is discussed.