Figure 7

Apoptosis ratios of J774A.1 cells induced by the fliY^- mutant and wild-type strain. Panel A: lower left quadrants indicate unstained normal cells; lower right quadrants, the early apoptotic cells binding Annexin-V; upper left quadrants, the necrotic cells binding PI; and upper right quadrants, the late apoptotic/necrotic cells binding both Annexin-V and PI. Cell death was measured by flow cytometry as described in Methods. Panel B: proportion of early apoptotic cells (annexin-V⁺/PI^-) after infection for different times. The data are expressed as mean ± SD for three independent experiments. Panel C: proportion of late apoptotic/necrotic cells (annexin-V⁺/PI⁺) after infection for different times. The data are expressed as mean ± SD for three independent experiments. *:P < 0.05, wild-type strain compared with the mutant.