FIG. 4.
Time course of bovine macrophage survival. (A) Survival after infection with wild-type Salmonella serovar Typhimurium grown to the logarithmic or stationary phase and a sipB mutant grown to the logarithmic phase. (B) Survival in the presence of a caspase inhibitor. Macrophages were incubated with the general caspase inhibitor Z-VAD-Fmk (25 μM) for 1 h prior to infection. To determine survival, macrophages were infected in 96-well plates, fixed at different times, stained with crystal violet, and analyzed by use of a microplate reader with a 630-nm filter. Values are means and standard deviations (n = 4).