Effect of VCAM-1–Fc and anti-β1 integrin mAbs on leukocyte adhesion to endothelium.
(A) Myelomonocytic HL60 cells were preincubated with medium alone (control), VCAM-1–Fc (40 μg/mL) with or without mAb anti–VLA-4 (α4 chain, HP2.1, 20 μg/mL), mAbs anti-β1integrin (K20), anti-α4 integrin (HP2.1), or the β2 integrin–activating mAb KIM185 (20 μg/mL each) or PMA (10 ng/mL) for 30 minutes at 37°C. After washing, adhesion to endothelial cell monolayers was performed. (B) HL60 cells (filled bars), U937 cells (gray bars), or isolated neutrophils (open bars) were preincubated with medium alone, VCAM-1–Fc (40 μg/mL), mAbs anti-β1 integrin LIA1/2 or K20, boiled mAb K20, isotype-matched irrelevant IgG2a, or anti-α4 integrin mAb HP2.1 for 30 minutes at 37°C. After washing, adhesion to endothelial cell monolayers was performed. Values are displayed as percentage of control and represent the mean ± SEM of at least 3 independent experiments. *Indicates P < .01 compared with control.
