Time-dependent formation of polymerized actin in human monocytes (5 × 10⁶/mL) without chemoattractant (○) and after stimulation with 10 nmol/L FMLP (•) or 0.14 (▪) or 0.43 (▴) CTA U/mL plasmin. Polymerized actin was quantified by flow cytometric analysis after staining with NBD-phallacidin. Results are the mean ± SEM of 4 experiments.