Role of Mac-1, α₄ integrins, and ICAM-1 for CXCL1- or PAF-elicited leukocyte responses. (A-B) Leukocyte rolling, (C-D) firm adherence, and (E-F) transmigration were quantified in postcapillary venules of the cremaster muscle using RLOT in vivo microscopy as detailed in “Quantification of leukocyte kinetics and microhemodynamic parameters.” Panels show results for PBS-treated WT control mice as well as for WT mice receiving blocking mAbs directed against Mac-1, α₄ integrins, ICAM-1, or isotype control after stimulation with CXCL1 or PAF (mean ± SEM for n = 4 per group; #P < .05, vs unstimulated; *P < .05, vs isotype control).