Expression of the tlr2, tlr4, tlr5, nlrp3 and nlrc4 receptor genes, il-18 and il-1β cytokine genes and caspase-1 and caspase-4 genes was quantified by RT-qPCR after 1, 3 and 6 h of bacterial infection (Figure 2A). Here, CASP1 is linked to bacterial infectious disease.