CASP3 and infection: The results showed that the levels of cleaved caspase-8, caspase-3, and PARP were higher in cells infected with ΔospC1 than in cells infected with WT Shigella. In contrast to infection with ΔospC1, infection with ΔospC1ΔospI did not lead to caspase-8, caspase-3, or PARP activation (Figs. 2G,H and EV2A–C).