FIG. 5.

HeLa cells infected during S phase are more susceptible than cells infected during G₁ to cell killing by the E1B 55-kDa mutant virus. HeLa cells were synchronized and cultured in six-well plates and then mock infected or infected with the wild-type virus dl309 or the E1B 55-kDa mutant virus dl1520 at MOIs of 3 and 10 at the onset of S phase or G₁. During a time course after infection, replicate dishes of cells were harvested and the percentage of live cells was determined by flow cytometry using the LIVE/DEAD assay as described in Materials and Methods. The data shown are from a single experiment and are representative of two independent experiments each performed in duplicate.