Surface TF exposure in response to eosinophil stimulation. (A) TF exposure elicited by GM-CSF/PAF. Left-hand panel: TF presentation on the surface of eosinophils was determined by flow cytometry using an FITC-labeled anti-TF antibody (▪). In parallel, the FITC-labeled control antibody was used (□). Activation of the eosinophils for the indicated time periods was performed by PAF alone (10 μM) or by GM-CSF (50 ng/mL) plus PAF. Means ± SEM, n = 4. *P < .05 (versus control). Right-hand panel: Contribution of de novo synthesized protein to TF exposure. Isolated eosinophils of 3 different donors were preincubated with cycloheximide or actinomycin D (both at 10 μg/mL; 30 minutes) and then stimulated for 45 minutes with GM-CSF/PAF. No statistically significant differences were seen between the mean values. (B) TF exposure in degranulating eosinophils as detected by immunoelectron microscopy. (C) Procoagulant activity of isolated eosinophils. Eosinophils activated by GM-CSF/PAF were lysed by freezing and thawing as described previously.30 In parallel, lysed monocytes previously activated with LPS were analyzed. The anti-TF antibody and isotype control IgG were present at 10 μg/mL. No cells indicates presence of coagulation factor concentrate alone. Means ± SEM, n = 4. *P < .05 (versus control of respective cell).
