FIG. 7.

Nlrc4 is required for pore formation. BMMs obtained from C57BL/6, caspase-1^−/− (Casp-1^−/−), and Nlrc4^−/− mice were infected at an MOI of 2, 10, or 100 of the wild-type L. pneumophila (A) or ΔflaA mutant (B) strain for 1 h and assayed for pore formation. (C) Proteins from uninfected cultures (NI) or BMMs infected with wild-type L. pneumophila (WT L.p.) or the ΔdotA mutant at an MOI of 10 for 1 h were separated by SDS-PAGE, blotted, and probed with a caspase-1 antibody. Indicated at left are procaspase-1 (45 kDa) and subunit p20 of active caspase-1 (20 kDa). (D) BMMs were pretreated with LPS for 4 h and either left uninfected (NI) or infected with wild-type L. pneumophila (WT L.p.) or the ΔdotA mutant for 1 h at an MOI of 10. IL-1β secretion was measured by ELISA. Data are representative of four independent experiments. *, P < 0.05 in comparison to C57BL/6 BMMs (A) or uninfected BMMs (D).