IL1B and infection: Importantly, IL-1β release was entirely dependent on NLRC4 upon infection with any of these different Pseudomonas aeruginosa strains, whereas the pyroptotic strains PAO1ΔExoS, CHAΔExoS and PP34ΔExoU triggered neutrophil lysis and IL-1β release that was fully NLRC4-dependent (Fig 2A).