Summary
The structural determinants of lipopolysaccharide required for the induction of tissue
factor in human umbilical vein endothelial cells were studied. Intact lipid A was
essential for the induction of tissue factor whereas the incomplete lipid A precursors
lipid IVA and lipid X, as well as monophosphoryl lipid A and acyloxyacyl hydrolase-treated
lipopolysaccharide, were unable to induce tissue factor and tissue factor specific
mRNA. However, the lipid A precursor, lipid IVA, was able to inhibit LPS-mediated induction of tissue factor; structural determinants
distal to lipid A were found to be required for maximal induction of tissue factor
activity and tissue factor mRNA. The presence of serum in the assay was found to amplify
but was not obligate for tissue factor induction by LPS.