Effect of anti–ICAM-2 mAb on IL-1β–stimulated leukocyte transmigration in the cremaster muscle and peritoneal cavity of WT and PECAM-1–deficient mice. Wild-type or PECAM-1–deficient mice were injected with intrascrotal (A) or intraperitoneal (B) saline/PBS or IL-1β (50 ng per mouse and 10 ng per cavity, respectively) 4 hours before quantification. In additional groups of mice, IL-1β–injected mice were also pretreated with an isotype-matched control antibody or the anti–ICAM-2 mAb 3C4 (both at 3 mg/kg intravenously) 15 minutes prior to administration of IL-1β. The data represent mean ± SEM from 2 to 9 mice per group in panel A and 3 to 7 mice per group in panel B. *P < .05, **P < .01, and ***P < .001 versus responses obtained from saline-injected animals. Additional statistical comparisons are indicated by lines.