Effect of acyclovir on various murine in vivo and in vitro immunologic assay systems.

In two in vitro tests, lymphocyte-mediated cytotoxicity and neutrophil chemotaxis, acyclovir showed no inhibitory effects at concentrations as high as 600 microM. The compound inhibited rosette formation with nonimmune mouse lymphocytes in vitro by approximately 50 percent at 15.8 microM. The significance of this inhibition is unclear. In four in vivo tests in mice which measured humoral and cell-mediated immunity (complement-dependent cellular cytotoxicity, complement-independent cellular cytotoxicity, delayed hypersensitivity and graft versus host reaction) acyclovir showed no inhibitory effects at single doses up to 200 mg/kg given on day 2 after antigenic stimulation. Four daily doses of acyclovir at 50 mg/kg per day had no effect on the numbers of hemolytic IgM antibody-forming cells in the spleen when assayed on day 4. At the higher dosage of 100 mg/kg per day for four days, there was a slight reduction in the numbers of these cells. There was no significant decrease in hemagglutinin or hemolysin antibody titers after four daily doses of acyclovir up to 200 mg/kg.