Lipopolysaccharide in the outer membrane of Gram-negative bacteria (LPS)

Lipopolysaccharide is a complex glycolipid forming the outer leaflet of the outer membrane of Gram-negative bacteria. It consists of three regions: lipid A (membrane anchor and endotoxin activity), core oligosaccharide (structural integrity), and O-antigen polysaccharide (serotype specificity and immune evasion). LPS is essential for bacterial survival, providing a protective barrier against toxic compounds, contributing to biofilm formation, and playing a key role as a pathogen-associated molecular pattern that triggers strong innate immune responses in host organisms. LPS is the principal cause of endotoxin-mediated clinical manifestations during Gram-negative infections, including sepsis and shock. Its diversity and capacity to evade immune responses present major challenges for therapy and diagnosis.

Other names

LipopolysaccharideLPSEndotoxin (when referring to its biological effects)Bacterial glycolipid

Drugs targeting LPS can disrupt outer membrane integrity, leading to increased permeability and bacterial death (e.g., colistin binds to lipid A, destabilizing the membrane). Blocking LPS recognition by host immune receptors (CD14/TLR4/MD2 complex), reducing proinflammatory cytokine release.