Mac-1 adhesion to ICAM-1 and ICAM-2 is attenuated when serine 1126 is mutated to alanine. (A) Jβ2.7 transfectants expressing wt CD11b were allowed to bind to wells coated with ICAM-1 or ICAM-2 at different ligand concentrations (microgram per milliliter of coated ligand) for 30 minutes. (B) Jβ2.7 transfectants expressing wt CD11b or S1126A-CD11b were allowed to bind to ICAM-1–coated wells (6 μg/mL coated ligand) without stimulation (control) or after stimulation with 100 nM PDBu or 5 mM MgCl2/1 mM EGTA for 30 minutes. Significant differences (P ≤ .02 for Mg/EGTA samples and P ≤ .002 for PDBu samples) in bracketed comparisons are indicated by a single asterisk. (C) As in panel B, except that ICAM-2 was used as the coated ligand. Significant differences (P ≤ .05 for unstimulated and Mg/EGTA-stimulated samples, P < .001 for PDBu-stimulated samples) in bracketed comparisons are indicated by a single asterisk. Error bars indicate SD.
