FIG. 2.

Effect of (S)-HPMPA and CDV on vaccinia virus DNA synthesis in vivo. BSC40 cells were cultured for 24 h, with or without the indicated concentrations of drugs, and then infected with vaccinia WR at a multiplicity of infection of 10. Fresh culture medium was added, also containing (S)-HPMPA or CDV where indicated, and then all of the nucleic acids recovered at 2, 4, or 6 h postinfection. A slot blotting protocol, followed by phosphorimager analysis, was used to quantify the amount of accumulated viral DNA (in arbitrary units) using a ³²P-labeled vaccinia DNA polymerase gene as a probe. The concentrations of each drug used correspond to the EC₅₀ (18 and 45 μM) and twice the EC₅₀ (36 and 90 μM) for (S)-HPMPA and CDV, respectively.