Fig. 3.

Comparison of the VB and EAVP80 viruses in normal HeLa-H cells and in PPMO-cured HeLa-H cells. (A) Growth characteristics of the VB and EAVP80 viruses in normal HeLa-H cells and in PPMO-cured HeLa-H cells. Subconfluent monolayers of normal HeLa-H and PPMO-cured PI97 HeLa-H cells were grown in 6-well plates and inoculated with each virus (moi of 3) at 37 °C for 1 h. After removal of the inoculum, the cells were rinsed three times with PBS and overlaid with 4 ml of EMEM. At indicated time points, supernatants were harvested and titrated by plaque assay. The average results from four experiments are shown. (B) Attempt to establish persistent infection with the VB and EAVP80 viruses in normal HeLa-H cells and PPMO-cured HeLa-H cells. Subconfluent monolayers of normal HeLa-H and PPMO-cured PI97 HeLa-H cells grown in T-25 flasks were inoculated with each virus at a moi of 3. Following 1 h adsorption at 37 °C, cell monolayers were washed three times with PBS and 10 ml of fresh culture medium was added. Inoculated cultures were incubated at 37 °C and subcultured once every 4 days. Tissue culture supernatants from serial subcultures up to the 10th passage were harvested and titrated for virus by plaque assay. The average results from three experiments are shown.