Caspase 3/7 activity detected by the Apo-ONE assay. Plotted relative to the increase in activity in uninfected cells induced by staurosporine, at three timepoints after infection with C. pneumoniae. Lanes A-H correspond to the conditions in panels A-H of figure 7. Lanes C, E and G depict decreased activity relative to uninfected control. Error bars are s.e.m. for 9 samples of 104 cells from 3 cell culture preparations.