F. tularensis LVS FTL_0699::Tn5 and FTL_0724::Tn5 transposon mutants modulated Francisella-induced caspase-1 activation. (A) Lysates from LPS-primed BMMϕ infected with LVS, the FTL_0699::Tn5 mutant, or the FTL_0724::Tn5 mutant (50:1 MOI) for the indicated times were immunoblotted with antibodies against the p10 subunit of caspase-1 or GAPDH. Data are representative of the results of two separate experiments. (B) Unprimed or LPS-primed BMMϕ were infected as described for panel A. IL-1β and IL-18 release into the supernatant 12 h postinfection was determined by ELISA. (C) Unprimed BMMϕ were infected as described for panel A; supernatants were collected at the indicated times postinfection, and IL-12 p40 and KC levels were assessed by ELISA. (D and E) LPS-primed BMMϕ from wild-type (WT), ASC−/−, caspase-1−/−, NLRP3−/−, NLRC4−/−, and AIM2−/− mice were infected as described for panel A. IL-1β and IL-18 release into the supernatant 9 h postinfection was determined by ELISA. (B, D, and E) Determinations were performed in triplicate, and the results are expressed as means ± SD. Data are representative of the results of two (E) or three (B and D) independent experiments. (C) Data are expressed as means ± standard errors of the means (SEM) of the results of three independent experiments. *, P ≤ 0.05.