Levels of TF expression in the culture medium of human pancreatic cell lines. Confluent cells were serum starved overnight and medium was prepared by centrifugation at 500g for 5 minutes and 1500g for 15 minutes. Levels of TF-positive MPs were determined by flow cytometry using a PE-labeled HTF-1 Ab (A). Levels of human TF protein were measured using a TF ELISA (B-C). Levels of TF activity on the MPs were measured using the MP TF activity assay (B-C). PS-positive MPs were measured using the Zymuphen MP-activity kit (B). All data are shown as means ± SD (n = 4). In panel C, the levels of TF protein and TF activity in the culture medium (CM), MPs, and MP-free supernatant (SN) were measured. The culture medium was centrifuged at 100 000g for 1 hour to pellet the MPs. Proteins in the SN were precipitated with ammonium sulfate. TF was detected by Western blot using specific Abs against flTF or asTF. Recombinant flTF (Innovin TF) and recombinant asTF were used as controls.