EFFECT OF HELICOBACTER-PYLORI LIPOPOLYSACCHARIDE (LPS) AND LPS DERIVATIVES ON THE PRODUCTION OF TISSUE FACTOR AND PLASMINOGEN-ACTIVATOR INHIBITOR TYPE-2 BY HUMAN BLOOD MONONUCLEAR-CELLS

Different Helicobacter pylori lipopolysaccharides (LPSs) and LPS-deriv atives were studied for their ability to induce the production of proc oagulant activity (PCA) and plasminogen activator inhibitor type 2 (PA I-2) by human blood mononuclear leukocytes, Smooth (S)- and rough (R)- form LPSs caused a similar increase in cell-associated PCA (tissue fac tor) and PAI-2 antigen release. Both effects were potentiated by fetal bovine serum via a CD14-mediated mechanism, The potency of H. pylori LPSs was similar to 1000-fold lower than that of Salmonella typhimuriu m LPSs. When H. pylori LPS derivatives (dephosphorylated R-LPS, S-lipi d A, and R-lipid A) were used, PCA and PAI-2 production were markedly reduced, R-lipid A was similar to 4-fold less efficient than S-lipid A , These findings suggest that the induction of monocyte tissue factor and PAI-2 by H. pylori LPS is influenced by the lipid A structure and modulated by the core oligosaccharide and that phosphate groups presen t in both regions may play an important role.