Antigenic TF. (A) HUVECs were treated with LPS (▨) or staurosporine (▪) or were kept in suspension with serum deprivation () for 2, 4, 8, and 16 hours. Cells were then lysed and prepared for quantitative determination of TF by ELISA. Functional TF in adherent (B) and suspended cells (C). HUVECs either untreated or activated with LPS for 6 hours were treated with staurosporine (B; solid triangles) or kept in suspension with serum deprivation (C; shaded triangles) for 8 hours. After incubation with factor VIIa and factor X, the formation of factor Xa was measured using a chromogenic substrate. Controls were untreated cells (B and C; ○) and cells treated with LPS (B and C; □). Results are expressed as means ± SD (n = 4).