LPS found in outer membrane of gram ⊝ bacteria.

Composed of O-antigen + core polysaccharid + lipid A (the toxic component).

Released upon cell lysis or by living cells by blebs detaching from outer surface membrane (vs exotoxin, which is actively secreted).

Three main effects:1. Macrophage activation (TLR4/CD14) → TNFα, IL-1, IL-6, NO2. Complement activation → C3a, C5a3. Tissue factor activation → Coagulation cascade → DIC