title: Procoagulant activity of human mononuclear blood cells (MBC). Stimulation by concanavalin A and mixed MBC culture.
abstract: Human mononuclear blood cells (MBC) express procoagulant activity PCA) upon stimulation in vitro. This thromboplastin activity is generated in monocytes under the influence of T-helper cell-derived signals. The own experiments described here served to establish the methodological basis for human MBC PCA generation in vitro and its measurement. Using Con A as stimulant it was shown that maximum PCA could be detected after 6-8 h of incubation. Incubation of the cells at 37 degrees C resulted in much higher PCA as compared to 40 degrees C. But in most experiments the specific differences between unstimulated controls and the Con A treated cells were more marked at 40 degrees C, because the "spontaneous" activation of controls occurred more slowly. The "spontaneous" activation of controls has been the most troublesome problem throughout the experiments, and was most likely due to traces of endotoxin in the media used. Choosing an incubation temperature of 40 degrees C it was shown that neither glass-adherent (AC) nor non-adherent cells (NAC) responded sufficiently to Con A when incubated separately. Addition of NAC to AC restored the capability to respond to Con A. NAC pulse-stimulated with Con A were able to activate AC. The same has been true for 20 h incubation supernatants of Con A-pulsed NAC. Finally, some two-way MBC mixed culture experiments are described which have been conducted under apparently endotoxin-free conditions. These results clearly show cellular PCA generation to be a sensitive indicator of allogenic recognition.
mesh_terms: D001779:Blood Coagulation Factors / Q000032:analysis*; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D009000:Monocytes / Q000187:drug effects*
chemical_list: D001779:Blood Coagulation Factors; C045071:leukocyte procoagulant activity; D003208:Concanavalin A