In vivo cytokine production induced by P. aeruginosa peritonitis. (A–C) WT mice were injected intraperitoneally with 1 × 107 CFU of either PA103 (n = 15 mice) or PA103ΔU (n = 15 mice); 4 h after infection, mice were killed and blood was collected by cardiac puncture. Serum IL-1β, IL-18, and TNFα concentrations were measured by ELISA. Data represent the mean ± the SEM. *, P = 0.036; **, P < 0.0001. (D–F) WT or IPAF−/− mice were injected intraperitoneally with 1 × 107 CFU of PA103ΔU; 4 h after infection, mice were killed and blood was collected by cardiac puncture. Serum IL-1β (n = 10 mice per group), IL-18 (n = 10 mice per group), and TNFα (n = 10 WT mice, n = 9 IPAF−/− mice) concentrations were measured by ELISA. Data represent the mean ± the SEM, ***, P = 0.023; ****, P = 0.014. (G) WT (n = 8), IPAF+/− (n = 6), or IPAF−/− (n = 10) mice were injected intraperitoneally with 5 × 106 CFU of PA103ΔU; 12 h after infection, mice were killed and peritoneal lavage with 10 ml of PBS was collected, spleens were removed and homogenized, and dilutions were plated on Vogel-Bonner minimal media for enumeration of CFUs. Bacterial counts from peritoneal lavage and spleen of IPAF−/− mice were significantly higher compared with WT mice (P < 0.0001 and P = 0.0009, respectively) and with IPAF+/− mice (P = 0.0005 and P = 0.0017, respectively).