In vitro effect of endotoxin from Shigella sonnei. phase I on human blood platelets and mononuclear leucocytes: comparison of "free endotoxin" with cell-extracted preparations
Miragliotta, G.; Semeraro, N.; Monno, R.; Colucci, M.; Fumarola, D.
Microbiologica 5(1): 35-42
1982
ISSN/ISBN: 0391-5352 PMID: 7050635 Document Number: 197014
The in vitro effects of a purified endotoxin preparation from culture fluids of S. sonnei, phase I, (purified free endotoxin, PFE) and 3 endotoxin preparations chemically extracted from the intact parent cells were investigated on human blood mononuclear leukocytes and platelets. PFE, like cell-extracted preparations, caused generation of strong procoagulant activity (tissue factor) by human mononuclear cells. PFE-stimulated cells developed significantly greater activity than cells stimulated by the other endotoxins; they had about 4-fold more activity. Neither free nor cell-extracted preparations induced aggregation in human citrated or heparinized platelet-rich plasma (PRP) or unmasking of platelet factor 3 (PF3). Thus, free endotoxin from S. sonnei, phase I, resembles endotoxin extracted from cells by conventional procedures in their interaction with human platelets and mononuclear leukocytes. In view of the possible contribution of free endotoxin to endotoxemia in human and experimental gram-negative sepsis, the data that free endotoxin stimulates human mononuclear leukocytes to produce a potent trigger of blood coagulation (tissue factor) may be relevant to the understanding of the mechanism(s) repsonsible for the initiation of intravascular coagulation in severe human infections.