Binding of PRT/heparin antibodies to antigens and to EA.hy926 cells. (A) Binding of PRT/heparin antibodies to PRT/heparin complexes, PRT/dextran, or PRT/EA.hy926. Plasma from 21 patients with CPB containing PRT/heparin antibodies were diluted 1:2000 in microtiter wells coated with PRT/heparin or PRT/dextran 10 µg/mL. For cell-based studies, fixed EA.hy926 cells were incubated with PRT 31 µg/mL for 1 hour at room temperature, followed by CPB samples (n = 21) diluted 1:500. (B-C) Correlation of PRT/EA.hy926 binding. Binding of PRT/heparin antibodies (n = 21) to PRT/heparin complexes (B) or PRT/dextran 10 µg/mL (C) is plotted as a function of PRT/EA.hy926 binding. All data shown are representative of 2 independent determinations.