The programmed cell death pathways apoptosis, pyroptosis, and necroptosis play critical roles in egress of intracellular pathogens.

<p>Intrinsic apoptosis is dependent on mitochondrial damage by Bax and Bak and activation of caspase-3. Caspase-3 can also be activated via cell surface receptors such as TNFR in the pathway of extrinsic apoptosis. Pyroptosis depends on caspase-1, which is activated by cytosolic NLRs, and caspase-11, for which the precise signaling pathway needs to be determined. Necroptosis requires Ripk1 and 3 and MLKL. Representative intracellular pathogens are listed that modulate these host suicide programs, either by blocking (red) or inducing (green) their activation.