EXPRESSION OF PROCOAGULANT ACTIVITY IN A HUMAN MONOCYTE-LIKE CELL-LINE

  • 1 January 1983
    • journal article
    • research article
    • Vol. 101  (3) , 401-410
Abstract
Peripheral blood monocytes generate the potent membrane-bound procoagulant TF [tissue factor] in response to a number of immune-related stimuli. Although the contribution of the monocyte/macrophage and its soluble mediators to the immune response was recognized, the role of macrophage procoagulants in the pathogenesis of this response is less certain. Previous studies have suggested that MTF [monocyte TF] generation is important in the pathogenesis of fibrin deposition in the inflammatory response. To pursue this relationship, the activation of a procoagulant was studied in a human monocyte-like cell line, the U937. The U937 procoagulant was characterized as TF by the following criteria: the PCA [procoagulant activity] requires factors VII and X for expression; the PCA is not due to serine protease activity; PCA is neutralized by a monospecific antibody to purified bovine TF. The expression of TF in these cells was amplified after stimulation with LPS [lipopolysaccharide], a potent activator of peripheral blood MTF expression, and was inhibited by actinomycin D and cycloheximide. Cytosine arabinoside, an inhibitor of cell division, failed to affect U937 TF generation. The U937 cell line appears to be a useful in vitro model for the study of the activation of MTF.