α2β1 integrin is required during the mast cell–dependent inflammatory response to zymosan. (A-C) Wild-type (WT) and α2 integrin–deficient (KO) mice were injected with zymosan intraperitoneally. At the indicated times after injection, the percent PMN, the absolute PMN number, and the IL-6 concentration in peritoneal fluid were determined. Shown is the combination of 2 experiments (mean ± SEM), with each group containing 5 or 6 mice.