Effect of APC on the HMGB1-mediated expression of cell adhesion molecules in HUVECs. Confluent HUVECs were incubated with HMGB1 (1 μg/mL for 16 hours) after treating cells with indicated concentrations of APC for 3 hours. The cell surface expression of VCAM-1 (A), ICAM-1 (B), and E-selectin (C) on HUVECs was measured by a cell-based ELISA as described in “Methods.” All results are shown as means ± SDs of 5 different experiments. *P < .05 and **P < .01 compared with HMGB1.