FIG. 3.

Treatment of EBV TK-expressing cells and control cells with nucleoside analogues in vitro. Cells were seeded into 96-well microtiter plates at 10³ cells/well. After allowing cells to adhere overnight, cells were incubated with GCV (A), PCV (B), ACV (C), BVdU (D), S-BVdU (E), or AZT (F) for 7 days. A colorimetric assay measuring the conversion of MTT to formazan was used to determine the fraction of cells surviving relative to untreated controls (100% viable). Each experiment was repeated three times, with each MTT absorbance value representing replicates of six wells. Each bar represents the average of three experiments, with error bars representing the standard errors of the means.