Neutrophil ICAM-1 does not support neutrophil transmigration in vivo. Extravasation of WT or ICAM-1 KO neutrophils was quantified using chimeric WT mice with a mix of WT-LysM-GFP and ICAM-1 KO (GFP-negative) neutrophils. Chimeric mice were stimulated with LPS (1000 ng IS or IP) and cremaster muscle tissues and peritoneal lavage fluid was collected and labeled with fluorescent antibodies against PECAM-1 and S100a9 (cremasters) or CD45 and Ly6G (lavage). (A) Representative image of extravasated WT and ICAM-1 KO neutrophils in LPS-stimulated cremaster muscles. (B-C) Quantification of extravasated WT-LysM-GFP and ICAM-1 KO neutrophils in saline and/or LPS-stimulated inflamed tissues. Values are normalized to the WT:KO ratio in the peripheral blood of each animal. Data are expressed as mean ± SEM of n = 6 to 10 animals/group. Statistically significant (t test or ANOVA) differences between stimulated and unstimulated treatment groups: *P < .05 and **P < .01.