Differential action of deoxynucleosides on mammalian cell cultures infected with herpes simplex virus types 1 and 2

Cytopathic effects induced by eight serologically defined isolates of herpes simplex virus type 2 (tested on human amnion cells) were markedly inhibited by thymidine at a concentration of 5 mM; eight serologically defined isolates of herpes simplex virus type 1, however, were not significantly inhibited. A similar effect was seen with thymidine, deoxyguanosine, and deoxycytidine at 1-mM concentrations in tests with rabbit kidney cultures. The inhibitory effect of thymidine was not blocked by the simultaneous presence of deoxycytidine, which has been shown by others to release mammalian cells from thymidine suppression. Differential suppression of herpes simplex cytopathic effects by these deoxynucleosides provides further evidence of biochemical differences between herpes simplex types 1 and 2. This phenomenon offers a basis for rapid differentiation of type 1 from type 2.