Effect of VIIa recycling on X activation.

BHK(TF) cells were treated with 10 nM VIIa at 37°C for 1 hour. Cell surface–associated VIIa was then removed by glycin wash, and the monolayers were washed 3 times with buffer B. Measurement of subsequent recycling of TF/VIIa activity at different time points was performed by incubating the cells with 100 nM X for 5 minutes and measuring the amount of Xa generated (♦). The activity of cells not preincubated with VIIa and not subjected to glycine wash (▴, ▪) and the activity of cells not preincubated with VIIa but washed with glycine (▵, ■) were measured for comparison at 10 and 240 minutes in the presence of 100 nM X (▴, ▵) or in the presence of 100 nM X and 10 nM exogenous VIIa (▪, ■).