Effect of anti–ICAM-2 mAb on IL-1β–elicited neutrophil migration into the peritoneal cavity of WT and ICAM-2–deficient mice. Animals were treated intraperitoneally with PBS or IL-1β (10 ng per cavity) 4 hours prior to peritoneal lavage. In additional groups of animals, mice were pretreated intravenously with anti–ICAM-2 mAb 3C4 (3 mg/kg) or isotype-matched control antibody (3 mg/kg) 15 minutes before the intraperitoneal administration of IL-1β. The figure shows the number of neutrophils that transmigrated into cavities. The data represent mean ± SEM from 3 to 8 mice per group. ***P < .001 versus responses obtained from saline-injected animals. Additional statistical comparisons are indicated by lines.