FIG. 2.

L. pneumophila activates caspase-1 through Asc, independent of the Ipaf/flagellin pathway. BMMs from wild-type (WT), Asc^−/−, Ipaf^−/−, or Casp1^−/− mice were infected with the indicated L. pneumophila variants at an MOI of 10. (A and B) IL-1β (A) and IL-18 (B) levels in culture supernatants at 8 h postinfection were quantified by ELISA. Data are represented as averages ± standard deviations. (C) Immunoblot of the p10 fragment of caspase-1 from combined supernatants and pellets of BMMs obtained at 4 h postinfection. Data are representative of four (A) or three (B and C) experiments. ND, measurable quantities not detected.