Figure 4. LsfA plays an important role in virulence in an acute pneumonia model.

(A) BALB/c mice were infected i.t. with 2×10⁶ bacteria per mouse with wild-type strain PA14 or the ΔlsfA or C45A mutants (n = 8 per group). Control mice were inoculated with PBS (n = 3) and the survival of the mice was followed for the course of the experiment. (B) At 24 hours post-infection, three animals were sacrificed, the organs were macerated, and the bacterial CFU were enumerated. (C) The cytokines in the lungs were determined by ELISA. (D) Mice were infected with PA14 or the C45A mutant. At 24 hours post-infection, the animals were euthanized, and the lungs were macerated. The cell suspensions were labeled for macrophages (F4/80⁺; CD11b⁺) or neutrophils (Ly6G/Ly6C⁺; F4/80⁻) and analyzed by FACS. (E) Mice were infected with PA14 or the C45A mutant. At 24 hours post-infection, the animals were euthanized, and the lungs were macerated, the cells were lysed by sonication and the suspension was centrifuged. The resulting supernatant was used for MPO activity assay with TMB., and OD was measured at 450 nm. The data are representative of three (B, C) or two (D, E). independent experiments independent experiments *, p<0.05; **, p<0.01; ***, p<0.001.