Mononuclear cell tissue factor: cell of origin and requirements for activation.

Human mononuclear leukocytes generate the procoagulant material tissue factor (TF) following stimulation by endotoxin, mitogens, or antigens in vitro. We have examined tissue-factor generation by mononuclear cell subpopulations prepared in a variety of ways in order to determine the cell of origin of mononuclear cell TF and the conditions necessary for maximal in vitro TF generation. We have also examined the relationship between in vitro TF generation and in vivo or in vitro measures of delayed hypersensitivity in response to identical antigen stimulation. Our results demonstrate that the monocyte is responsible for the bulk of mononuclear cell TF generation in vitro and that adhesion alone is not sufficient stimulation for significant.