Role of EPCR and PAR1 on APC-induced MP release. HUVECs (light gray bars) and monocytes (dark gray bars) were incubated with APC 100 nM for 2 hours in the presence and absence of the EPCR-blocking antibody RCR-252, the PAR1 antibody, ATAP2, and the PAR1 antagonist peptide T1. Panel A shows the changes in EPCR surface expression by flow cytometry using RCR49 in HUVECs and monocytes; panel B quantifies the MPs released from HUVECs and monocytes by their APC content through ELISA capture and chromogenic S2366 detection. Results are representative of 3 experiments. Values are mean ± SD; *P < .005.