P-Rex and Vav are required for neutrophil recruitment to the acutely LPS-inflamed lung. (A) Reduced pulmonary neutrophil recruitment in P1V1 and P1V3 mice during LPS-induced acute lung inflammation. Mice were challenged intranasally with 200 μg/kg LPS or carrier (Con), and pulmonary recruitment of neutrophils (i) or total leukocytes (ii) were assessed after 4 hours by lung lavage, as were neutrophil numbers in peripheral blood (iii). Data are mean ± SEM of 3 experiments with 5 to 8 mice/group; statistics unpaired Student t test between sham and LPS treatment and Kruskal-Wallis test with Dunn’s multiple comparisons (i,ii) or 2-way ANOVA with Bonferroni multiple comparisons (iii) for genotypes. (B) Reduced LPS-induced neutrophil infiltration into lung tissue of P1V1 and P1V3 mice. H&E-stained mouse lung histology slides prepared after LPS challenge as in (A). Black arrows indicate blood vessels, white arrows airway walls, and the red arrow infiltrated neutrophils. Photographs represent 4 to 9 mice per group. The size bar represents 50 μm. The grey-scale insert in the PVWT/LPS panel is a ×2.5 magnification of the red frame. Neutrophils are identified by their characteristic donut- or horseshoe-shaped nuclei and are marked with dots. (C,D) Reduced leukocyte transmigration and airway infiltration in lung tissue of P1V1 and P1V3 mice. Leukocyte transmigration into lung tissue (C) and airway infiltration (D) in response to LPS challenge quantitated from histology slides, as in (B), as leukocytes within a radius of 50 μm of blood vessels or 50 μm of the airway wall, respectively, with multiple measurements per slide. Data are mean ± SEM of n = 4 to 9 mice per genotype; statistics 2-way ANOVA with Bonferroni multiple comparisons.