Consistent with this finding, there was no detectable caspase-3 cleavage, indicative of apoptotic caspase activation, in either the ΔflaA- or ΔflaA/ΔsidF-infected BMDMs after 8, 12, and 24 h of infection, as determined by immunoblotting of the caspase-3 p17/p19 fragment (Figure 2C). Here, CASP3 is linked to infection.