S1126A-mutated integrins have lower affinity for a soluble ICAM ligand, and migration through SDF-1–activated endothelium is attenuated. (A) The effect of the S1126A mutation on soluble ICAM-2 binding of Mac-1 was determined. Jβ2.7 transfectants were incubated with 200 μg/mL ICAM-2Fc, and binding was determined by flow cytometry. (B) Jβ2.7 transfectants were incubated with 200 μg/mL iC3b, and binding was determined by flow cytometry. (C) Transendothelial migration through nonstimulated or SDF-1α–activated endothelium was determined as described in “Materials and methods.” Significant differences (P ≤ .02) in bracketed comparisons are indicated by a single asterisk. Error bars represent SD.