MK binding to PMNs did not require CD18 or CD29. (A-C) Analysis of binding of Alexa Fluor 488-labeled MK to murine PMNs using flow cytometry. For control, PMNs were left unstained. (A-B) Cells were left untreated for control (w/o) or stimulated with TNF-α (100 ng/ml), CXCL1 (100 ng/ml), or MnCl₂ (3 mM) for 20 minutes at 37°C. (A) Binding of MK to isolated PMNs from CD18^+/+ or CD18^−/− mice. (B) Binding of MK to isolated PMNs from CD29^+/+ or CD29^−/− mice. (C) Binding of MK to PMNs from WT mice. The α₄ subunit was blocked with the anti-CD49d antibody or left unblocked (untreated), and the rat IgG_2b antibody was used as control. Blocking was performed for 20 minutes at RT and cells were subsequently left unstimulated (w/o) or stimulated with TNF-α (100 ng/ml), or CXCL1 (100 ng/ml) for 20 minutes at 37°C. Histograms (A-C) are representative of 3 independent experiments.