FIG. 6.

The pan-caspase inhibitor zVAD-FMK protects NS1-expressing and H-1PV-infected cells from undergoing apoptosis. 293-NS1 cells grown in medium supplemented (induced) or not supplemented (noninduced) with doxycycline, and HEK-293 cells either mock treated or infected with H-1PV (MOI, 10 PFU/cell), were treated with the pan-caspase inhibitor zVAD-FMK (10 μM) for 72 h. (A, C) Cultures were analyzed by flow cytometry, as described in the legend to Fig. 5, for the determination of the sub-G₁ cell population. Results are presented as average values with standard deviation bars from three independent experiments, each performed in triplicate. (B, D) Cell lysis of NS1-expressing and H-1PV-infected cells treated with zVAD-FMK was determined by LDH assay.