Assessment of neutrophil recruitment in vivo secondary to LPS-induced inflammation in the lung in Srf WT and KO mice. BAL was performed in Srf WT and KO mice before and 4 and 24 hours after LPS nebulization. Total (A), neutrophil (B), and macrophage (C) cell numbers were determined in BAL. (Combined data from 2 independent experiments: 0 hours, n = 4; 4 hours, n = 5; 24 hours, n = 4; *P < .05; **P < .005; ***P < .0005). Macrophage and neutrophil percentages were determined on Wright Giemsa–stained cytospins and by flow cytometry. (D-F) Migration of Srf WT and KO neutrophils in vitro in a transwell assay and chemokine receptor expression. Srf WT and KO neutrophils were allowed to migrate across 3-µm pore membrane toward an fMLP (D) and CXCL1 (E) gradient at indicated concentrations. Representative experiments performed in triplicate of at least 3 independent experiments (**P < .005; ***P < .0005). mRNA expression of chemokine receptors was assessed in Srf WT and KO neutrophils (F).