APC does not lead to increased surface expression of TF or availability of anionic phospholipids. TNFα- or control-treated cells were incubated for 3 hours with the indicated agonists. (A) Surface expression of TF was determined by immunoassay using monoclonal anti-TF. Prothrombin activation (B) and annexin V binding (C) were analyzed on the cell surface as measures of negatively charged phospholipids as described in “Reagents, antibodies, and assays.” HgCl₂ was added only for 30 minutes. Agonists were removed by washing steps before the assays were performed. Means ± SEM with n = 6 are shown.