Figure 7.

Sindbis vector infection causes caspase cleavage. (A) Sindbis vector infection leads to significant cleavage of caspase 9 but minimal amounts of caspase 8. MOSEC cells infected with SV or mock infected were assayed 24 h.p.i. for caspase activation using fluorescent probes specific for individual caspase cleavage products. Scale bars for panel A indicate 100 μm. (B) Infection with Sindbis viral vector results in the cleavage of caspase 3. MOSEC cells infected with SV or mock infected were assayed at 24 h.p.i. for caspase 3 cleavage using a cleavage specific fluorescent probe. Scale bars indicate 10 μm. (C) Treatment with selective caspase inhibitors can protect cells from a loss of cell viability. MOSEC or Pan02 cells were infected with Sindbis vector or mock infected and then incubated with caspase specific peptide inhibitors. Cell viability was assessed at 24 h.p.i. Cell viability indicates that cells treated with a broad caspase inhibitor, caspase 3 inhibitor or caspase 9 inhibitor are protected from apoptosis whereas samples treated with caspase 8 inhibitor were not. Data in C represents the SEM (error bars) of three experiments. Each sample was compared to the infected control at the same time point. Statistical significance was calculated by a two-tailed student t-test (* P < 0.05, ** P < 0.005).