M. Gupta et al., EXPRESSION AND LOCALIZATION OF TISSUE FACTOR-BASED PROCOAGULANT ACTIVITY (PCA) IN PIGEON MONOCYTE-DERIVED MACROPHAGES, Thrombosis and haemostasis, 70(6), 1993, pp. 963-969
Monocyte-derived macrophages, focal to initiation and progression of a
therosclerosis, have been implicated in thrombotic complication of thi
s disease. In the present study we demonstrated tissue factor based pr
ocoagulant activity in cultured macrophages from the White Carneau pig
eon following endotoxin (1-2 mu g/ml) stimulation. This macrophage pro
coagulant activity paralleled activity obtained with pigeon brain homo
genate. We used Enzyme-Linked Coagulation Assay (ELCA), an ultrasensit
ive microtiter plate assay, io measure procoagulant activity in these
cells. Through the use of clotting factors purified from pigeon plasma
, procoagulant activity could be detected with as few as 1-3 cells. Ti
ssue factor antigen, detected through the use of immunogold labelling
in conjunction with a polyclonal antibody which was highly specific to
human tissue factor, was distributed uniformly over the plasma membra
ne of the endotoxin-stimulated cells. These studies suggest that this
procoagulant activity might play an important role in the pathobiology
of atherosclerosis in White Carneau pigeons by initiating fibrin poly
merization and thus leading to thrombotic complications of the disease
.