fMLP-induced binding of VCAM-1 and LDV-FITC to U937-FPR cells is similar. (A) A time course of VCAM-1 monomer binding stimulated with fMLP is shown (mean ± SEM; n = 3). Asterisks indicate values that differ significantly (P < .05) from the control (0 time point). (B) The effects of inhibitors on fMLP-induced binding of LDV-FITC, VCAM-1, and VCAM-1/Fc were compared. U937-FPR cells were pretreated with various inhibitors used at the same concentrations as in previous figures or with vehicle. For each ligand and inhibitor, the increase in ligand binding to cells stimulated for 3 minutes with fMLP (100 nM) relative to unstimulated cells was determined, and data were normalized to cells pretreated in parallel with vehicle or buffer.