Effect of acyclovir on the proliferation of human fibroblasts and peripheral blood mononuclear cells.

The effect of acyclovir on human cells was measured. A concentration of 50 to 100 microM inhibited the division of fibroblasts to a variable extent, depending on the experimental design and the confluency of the monolayer. The magnitude of this effect was less than that caused by human leukocyte interferon when these antiviral agents were compared at clinically relevant concentrations. Acyclovir also inhibited thymidine incorporation by peripheral blood mononuclear cells stimulated by either phytohemagglutinin or three different herpesvirus antigens. A linear dose-response curve was observed with these cells, and their proliferation was inhibited 50% by 100 microM acyclovir. Inhibition was exerted on T-cell proliferation without apparent effect on the release of lymphokines or on monocyte function.