Macrophage migration in vitro requires Mac-1. Migration of LPS-stimulated WT (open bars) and Mac-1^-/- (filled bar) peritoneal macrophages was determined using transwell plates with a 5-μm pore insert in the presence or absence of anti-Mac-1 (M1/70), control IgG (IgG) or EDTA. The total number of macrophages within the lower chamber was determined manually by hemocytometer and normalized for the percentage of macrophages based on Hema3-staining of Cytospin smears. The number of migrated WT macrophages is assigned to 100%. The data represents mean ± SD of 3 to 5 independent experiments. ^*P < .001 for WT versus Mac-1^-/- and M1/70 versus IgG.