FIGURE 9.
Effect of APC(S360A) on thrombin generation in extrinsically triggered FVLeiden plasma in the presence and absence of FVIII antibodies. Thrombin generation was triggered by the addition of 3.4 pm TF and 30 μm phospholipid vesicles (20:60:20, DOPS:DOPC:DOPE), and CAT was performed as described under “Experimental Procedures.” Varying total concentrations of APC(S360A) ([APC(S360A]o) were added to plasma from a carrier of the FV R506Q mutation in the absence (●) or presence (○) of a FVIII inhibitory antibody. Either 1.5 μl of polyclonal goat anti-human FVIII (final concentration, 54 BU/ml) or the same volume of buffer was added in a total reaction volume of 125 μl, and the plasma was incubated for 15 min at 37 °C prior to initiating thrombin generation. The average thrombin peak concentration ± S.E. (Thrombin peak) from two different experiments is plotted as a function of the total concentration of APC(S360A).