FIG. 6.

L. pneumophila pathways for caspase-1 activation do not involve Nalp3 or the proteasome. (A) BMMs from wild-type (WT), Asc^−/−, Nalp3^−/−, or Casp1^−/− mice were infected with wild-type or flaA L. pneumophila at an MOI of 10 and assayed for IL-1β in supernatants at 8 h postinfection. (B and C) Wild-type or Asc-deficient (Asc^−/−) BMMs were pretreated with LPS (1 μg/ml) for 3 hours, followed by infection with wild-type or dotA L. pneumophila in the presence of dimethyl sulfoxide (DMSO) (mock treated) or MG132 and assayed for IL-1β or IL-18 in culture supernatants at 6 h postinfection. Data are represented as averages ± standard deviations. (D) LDH release assays were performed at 6 h postinfection for wild-type macrophages infected with wild-type or dotA L. pneumophila in the presence or absence of MG132. Values represent the percentage of LDH released compared to that for cells lysed with Triton X-100. Data are represented as averages ± standard deviations. Data are representative of two experiments.