FIG 4.

Effects of dose and duration of infection on host cell antiapoptotic activity. (A) RAW264.7 cells were infected as described in Materials and Methods with E. faecalis E99 at an MOI of 0.5, 1, 10, or 20. Apoptosis was induced at 12 h postinfection with 1 μM staurosporine for 5 h. (B) RAW264.7 cells were infected with E99 at an MOI of 10, and apoptosis was induced at 2, 12, and 24 h postinfection with 1 μM staurosporine for 5 h. Western blots of cell lysates at the indicated time points were processed for detection of cleaved caspase 3 levels. Cleaved caspase 3 levels were normalized by actin densitometry, and fold activations relative to untreated samples were determined. The graphs show the relative ratios of cleaved caspase 3, which are averages of three independent experiments and SD.