Figure 5.

Effect of anti-ZPI antibodies on factor Xa-induced coagulation of plasma. Reaction mixtures (200 μl) containing factor Xa (0.125 nM), CaCl₂ (5 mM), and cephalin (18.75 μM), with or without PZ (50 nM), were incubated in the sample cup of a fibrometer. After 2 min at 37°C, 50 μl of factor X-deficient plasma that had been treated with rabbit preimmune IgG (600 μg/ml) or various concentrations of immune anti-ZPI IgG for 30 min was added and the clotting time was measured. Apparent factor Xa inhibition (76%) produced by the inclusion of PZ during the preincubation period and using plasma treated with preimmune IgG is listed as maximal PZ-dependent inhibition (100% on the ordinate). The concentration of anti-ZPI IgG used to treat the plasma is listed on the abscissa. Note that the range of “% Maximal Inhibition” listed on the ordinate is plotted from 40 to 100.