Figure 2. Characterization of PMN leukoctye–FXIa interaction.

Purified human PMN leukoctyes (1×10⁶/ml) were incubated over surfaces of FXIa (50 μg/ml) for 30 min at 37°C in the presence of vehicle (PMN leukoctye buffer; –), EDTA (5 mΜ), AnnexinV (AnxV; 10 μg/ml), or serine protease inhibitor PPACK (40 μΜ). In selected experiments, cells were treated with Zn²⁺ (25 μΜ) and HK (42 nΜ). Results are reported as mean cell count/mm² ± sem of three independent experiments. P < 0.05 compared with adhesion of vehicle-treated cells in the absence (*) or presence (**) of Zn²⁺/HK.