Effect of dual and triple blockade of ICAM-1–, JAM-A–, and PECAM-1–dependent pathways. (A) WT, ICAM-2^−/−, or JAM-A^−/− mice were given an intrascrotal injection of IL-1β (50 ng) or saline (control). Additional groups of mice were pretreated with an anti–JAM-A mAb (BV-11), anti–ICAM-2 mAb (3C4), or an appropriate control mAb (all at 1 mg/kg intravenously), as indicated. Four hours after the administration of IL-1β, cremaster muscles were exteriorized and leukocyte transmigration was quantified by intravital microscopy, as detailed in “Intravital microscopy.” (B) WT mice were pretreated with submaximal doses of an anti–PECAM-1 mAb (Mec 13.3), a cocktail of blocking mAbs directed against ICAM-2, JAM-A, and PECAM-1, or control mAbs as appropriate (all at 1 mg/kg intravenously). IL-1β (50 ng) or saline was injected intrascrotally; and after 4 hours, leukocyte responses of adhesion and transmigration were quantified. Results are mean ± SEM from n = 4 to 10 mice/group. Statistically significant differences between control and stimulated groups are indicated as follows: **P < .01, ***P < .001. Additional statistical comparisons are indicated as follows: #P < .05, ## P < .01.