Inhibition of function of platelet and endothelial ERp5 with anti-ERp5 antibody. Inhibition of disulfide reductase activity on the activated cell surface of human platelets and HUVECs measured in the di-E-GSSG reduction assay. (A) Percent reductase activity of platelets in the presence of anti-ERp5 antibody (0.3 µM, gray; 1.2 μM, white) compared to reductase activity of platelets in the presence of control IgG (1.2 μM, black). (B) Percent reductase activity of HUVECs in the presence of anti-ERp5 antibody (0.3 µM, gray; 2.2 μM, white) compared to reductase activity of HUVEC in the presence of control IgG (2.2 μM, black). N = 3 in triplicate; *P < .05. (C) Inhibition of mouse platelet aggregation with anti-ERp5 antibody. Platelets were incubated with control IgG or anti-ERp5 antibody (0.2 μM) and subsequently stimulated with thrombin (0.2 U/mL).