FIG. 4.

EBV-infected cells are resistant to apoptosis. EBV-negative [EBV(−)] and EBV-positive [EBV(+)] clones derived from the parental Akata cells (A) and neoR-transfected, EBV-reinfected, and EBNA-1-transfected clones derived from an EBV-negative Akata clone (B) were exposed to apoptotic stimuli. The average relative survival rates (percent) and error bars (standard errors of the means) are shown. (A) The average relative survival rate of the EBV-positive clones is significantly higher than that of the EBV-negative clones (∗, < 0.001), suggesting that EBV-positive cells are resistant to apoptosis because of the presence of EBV in cells. The data presented here are typical results from three independent experiments. (B) The average relative survival rates of reinfected clones are significantly higher than those of NeoR- and EBNA-1-transfected clones (∗∗, < 0.005; ∗∗∗, < 0.05), suggesting that EBV-infected cells are resistant to apoptosis because of the presence of EBV in cells. The data presented here are typical results from three independent experiments. The numbers of clones tested are noted beneath the graph. Significance values between the indicated groups were determined by unpaired Student’s t test.