Effect of different inhibitors on PF4-mediated neutrophil adhesion. Freshly isolated neutrophils (1 × 106 cells/mL) were pretreated for 20 minutes with increasing concentrations of piceatannol, manumycin A, or SP600125, a constant dosage of cytochalasin B (CytoB; 5 mg/mL), or without inhibitor and subsequently were incubated with 2 μM PF4 in the presence of a monolayer of cultured endothelial cells. After 20 minutes, nonadherent cells were removed and residual neutrophils were determined. Cell amounts in samples receiving PF4 in the absence of any inhibitor were set at 100%, and data were calculated as the percentage of these controls. Data represent mean ± SD of 3 (manumycin A) or 4 (piceatannol, SP600125, and cytochalasin B) independent experiments, each performed in duplicate. Statistical analysis using one-way ANOVA indicates significant differences (*P < .025) between inhibitor-treated and untreated samples based on the data from 3 or 4 individual experiments.
