TF-specific binding, internalization, and degradation of VIIa in BHK cells.

¹²⁵I-VIIa (10 nM) was added to confluent monolayers of BHK cells (■) or BHK cells transfected with full-length TF (BHK(TF)) (▪) that were preincubated for 60 minutes with control buffer or 200 μg/mL rabbit antihuman TF IgG at room temperature. Cell surface association (A), internalization (B), and degradation (C) were determined at various time points as described in “Materials and methods.” TF-specific binding, internalization, and degradation were determined by subtracting the values obtained in the presence of antihuman TF IgG from the values obtained in its absence. Nonspecific binding of ¹²⁵I-VIIa to BHK(TF) cells in the presence of antihuman TF IgG was 10% to 15% of the total binding. A similar amount of ¹²⁵I-VIIa was bound to parental untransfected BHK cells in both the absence and presence of antihuman TF IgG. Data are the mean ± SD of 3 independent experiments in triplicate.