Major differences in TF activity and protein levels between monocytes and granulocytes. A clear reduction in TF protein levels was observed when purified si-TF–nucleofected monocytes were reintroduced into whole blood predepleted for monocytes (A). The decrease in TF protein levels was accompanied by a reduction in TF procoagulant activity in MNC lysates (B). Granulocytes, isolated from LPS-stimulated whole blood, possessed almost 200-fold weaker TF activity than MNCs from the same blood aliquot (C). Stimulation of granulocytes with LPS/PMA, GM-CSF/PAF, and P-selectin did not induce any detectable TF protein levels (D) or TF activity (E) in contrast to monocytes. Data are means (± SEM). NS indicates nonstimulated; CTR, 2h, time-matched control; and ND, nondetectable. *P < .05 compared with respective nonstimulated controls. P < .05 compared with nonsilenced LPS-stimulated monocyte samples. **P < .05 compared with samples from unstimulated MNC fraction.