Fig. 2

Caspase-3, caspase-8, and caspase-9 activity in RAW264.7 cells infected with WT S. Typhimurium, ΔsseK3 mutant, or sseK3-complemented strains. Caspase-3, − 8, and − 9 activity was measured by colorimetric assay and analyzed using two-way ANOVA with Bonferroni’s multiple-comparison test (*P < 0.05,**P < 0.01,***P < 0.001). Results are shown as mean ± SD