Figure 3.

Reduction of neutrophil airspace influx does not significantly attenuate alveolar barrier disruption in thrombocytopenic Mpl^−/−mice following either live PA challenge or PA SN-induced sterile injury. (A) Schematic of experimental design: Mpl^−/− mice were administered Ly-6G or isotype control antibody (Ab) at −24 hours and inoculated with PA at 0 hours, and necropsy was performed 20 hours after PA lung infection. (B) Reduction of circulating neutrophil counts (10⁹/L blood) after anti-Ly6G. In separate experiments, mice were given either 10⁶ live bacteria (C-G) or mice were given cell-free PA SN and a second dose of antibody at t = 0 hours (H-K). Following live bacterial challenge, lung CFU/mL (C), BAL neutrophil counts/mL (D), gross appearance of BAL fluid (E), BAL OD₅₄₀ (F), and BAL IgM concentrations (ng/mL) (G) were obtained at necropsy 20 hours after 10⁶ CFU IT PA. n = 6 mice/group. There was 1 death in the isotype control group prior to the 20-hour time point. Following PA SN-induced sterile injury, BAL neutrophil counts/mL (H), gross appearance of BAL fluid (I), BAL OD₅₄₀ (J), and BAL IgM concentration (ng/mL) (K) were obtained at necropsy. n = 6 mice/group. There was 1 death in the isotype control group prior to the 20-hour time point. Each tube or point represents an individual mouse, and the group median is displayed. Statistical comparison by Mann-Whitney U test. **P < .01.