Merck, L4391-1MG, Lipopolysaccharides from Escherichia coli O111:B4

Lipopolysaccharides (LPS) are intricate molecules consisting of lipids and polysaccharides, predominantly present in the outer membrane of Gram-negative bacteria. Comprising lipid A, the core oligosaccharide (core), and the O-specific polysaccharide or O antigen (OAg), LPS is anchored to the outer bacterial membrane, with lipid A primarily responsible for its associated toxicity. Functioning as a potent activator of the proinflammatory response, LPS engages various mammalian cells, including macrophages, monocytes, and endothelial cells. While serving a protective role for Gram-negative bacteria against environmental stress, LPS also triggers recognition by the innate immune system during infections.