CASP1 and infection: Infection with the HND115 strain resulted in an increased number of AnnexinV/PI-positive cells compared to cells infected with the wild-type and the complemented strain (Fig. 5); furthermore, the lack of apyrase indirectly induced caspase-1 activation which, in turn, leads to gasdermin D cleavage and pro-IL-1β processing, thereby triggering pyroptotic cell death (Fig. 6).