Effect of cytokines on caspase-3 activation. PMN were stimulated for indicated times with 300 U/mL TNF-, 300 U/mL GM-CSF, or left untreated (control), respectively. (A) After stimulation for indicated times, whole-cell lysates were subjected to SDS-PAGE and Western blot was performed using the anti-caspase-3 Ab and a peroxidase-conjugated secondary antibody. Numbers indicate mean OD of each lane obtained from three representative and independent experiments. (B) Caspase-3 activity was measured in whole-cell lysates obtained from PMN, which were treated for 1 hour at 37°C with 200 μmol/L of the caspase-3 inhibitor Z-DEVD-FMK or left untreated (vehicle) before stimulation for 2 hours as indicated. Caspase-3 activity is shown as mean fluorescence intensity ± SD obtained from three independent experiments. *P < .05; #P < .05 versus unstimulated control; n.s., not significant.