Lipid A precursors protect against endotoxin challenge.

These studies provide exciting prospects for the future treatment of gram-negative infections. The anti-endotoxin activity of lipid X, a monosaccharide precursor of lipid A, may be a prototypic compound for agents that can block the toxic effects of endotoxin that is being actively released. In contrast, monophosphoryl lipid A, a disaccharide derivative of lipid A, stimulates host defenses against infections and tumors. With further understanding of the mechanisms by which these compounds exert these effects, we can anticipate that new and more active compounds will be developed and that further activities of existing compounds will be found.