RIAM^−/− mice suffer from LAD and extravasation defects. (A) β2 integrin-mediated adhesion of PMNs from wt, RIAM^−/−, and talin-1^−/− mice under flow ex vivo. Flow chambers were coated with E-selectin only or a mixture of E-selectin, ICAM-1, and/or CXCL1 (K), connected to the carotid artery and perfused with whole blood for 10 minutes (n ≥ 4 chambers in 3 independent experiments for each condition). (B-C) Mean rolling velocity (B) and adhesion efficiency (C) of PMNs in TNF-α–stimulated postcapillary cremaster muscle venules of wt, RIAM^−/−, and talin-1^−/− mice (n = 4 independent experiments). (D) Quantification of perivascular PMNs after Giemsa staining of TNF-α–stimulated cremaster muscles 3 hours after cytokine application (n ≥ 5 independent experiments). (E) Adhesion efficiency of leukocytes in unstimulated cremaster muscle venules of wt and RIAM^−/− mice before and 2 minutes after injection of the arrest chemokine CXCL1 (n = 4 of 6 independent experiments). (F) Adhesion efficiency of PMNs in TNF-α–stimulated postcapillary cremaster muscle venules of BM mixed chimeras analyzed 8 weeks after transplantation (n = 4 independent experiments). (G) Whole-mount staining of phorbol ester–treated ears from wt and RIAM^−/− mice, stained with an anti-pan-laminin antibody (LN, green) to visualize endothelial basement membranes and an anti-Gr-1 antibody to identify neutrophils. Arrowheads indicate extravasated cells; arrows point to neutrophils within blood vessels. Scale bar represents 100 μm. (H-I) wt and RIAM^−/− mice were exposed to aerosolized LPS for 30 minutes and ratios of neutrophils extravasated into the interstitium (H) or the brachioalveolar space (I) and neutrophils remaining in the lung vasculature are shown 4 hours after treatment. Data are shown as mean ± SEM P values indicate significant differences and were calculated with the Student t test. E, E-selectin; EI, E-selectin and ICAM-1; EIK, E-selectin, ICAM-1 and KC.