However, CASP8 siRNA knockdown in CASP1−/− Caco-2 cells did not abrogate inflammasome activation during Δ6 Yptb infection (Fig. S2F and G), indicating that additional caspase activation pathways likely mediate cell death during Δ6 Yptb infection of human IECs. This evidence concerns the gene CASP1 and infection.