FIG. 6.

PGE₂ delays the generation of IFN-γ⁺ T cells and inhibits effective clearance of F. tularensis from the lung. C57BL/6J mice were inoculated with F. tularensis LVS either intradermally (10⁵ CFU) or intranasally (5 × 10² CFU). (A) BALF was collected from all mice (n = 8) at indicated time points. BALF was analyzed for the concentration of PGE₂ using a standard ELISA. (B, C, D) C57BL/6J mice were inoculated with F. tularensis LVS intranasally (5 × 10² CFU). At days 5, 6, and 7 postinoculation, mice were treated with 1 mg/kg indomethacin in intraperitoneal injections. Untreated mice were injected with 1% DMSO. (B) On day 7, BALF was isolated from all mice and analyzed for the concentration of PGE₂ using a commercial ELISA. (C) On days 7, 10, and 14 postinoculation, cells were isolated from the lungs of all mice. T cells were then analyzed for IL-17 and IFN-γ. (D) On days 7, 10, and 14 postinoculation, the bacterial load was determined in the lungs of all mice. Panel A comparisons are between routes of inoculation at each given time point; panel B, C, and D comparisons are between treated mice and untreated mice. Asterisks denote statistical difference (*, P ≤ 0.05; **, P ≤ 0.01, ***, P ≤ 0.001). Error bars represent standard errors of the means (n = 8). Data represented are combined from two experiments with four mice per group for a total of eight mice per group per time point.