Ipaf responds to P. aeruginosa expressing flagellin. (A) Diagram of flagellar structure formed by WT P. aeruginosa or the amotile flgK, fliC, and flgB mutants. (B) IL-1β secretion by LPS-primed WT macrophages infected with WT P. aeruginosa, amotile mutants expressing flagellin monomer (flgK), or amotile mutants not expressing flagellin monomer (fliC or flgB). (C) Caspase 1 processing in macrophages infected with P. aeruginosa mutants was examined by Western blot. (D) IL-12 p40 secretion was determined by ELISA from macrophages infected with P. aeruginosa strains for 1 h, washed, and treated with gentamicin for four additional hours. (E) The motility phenotype of strains was confirmed in soft agar. The asterisk denotes a nonspecific band.