Endotoksinin

Endotoksinin, commonly known as endotoxin, is a heat-stable component of the outer membrane of most Gram-negative bacteria. It is a complex of lipopolysaccharide (LPS) that consists of lipid A, a core polysaccharide, and an O-antigen. Lipid A is the primary source of endotoxin activity and is responsible for triggering most of its biological effects.

Biological activity arises when endotoxin is released during bacterial growth or cell lysis. In humans, it is recognized by a chain of innate immune receptors, including LPS-binding protein, CD14, and the TLR4–MD-2 complex. This engagement activates inflammatory signaling pathways, leading to the release of cytokines such as TNF-α, IL-1, and IL-6. The response can range from fever and inflammation to severe vasodilation and septic shock in extreme cases.

Clinical relevance centers on infections with Gram-negative bacteria and the risk of endotoxemia. Endotoxins are also a concern in the production of pharmaceuticals and vaccines, where even trace amounts must be controlled. Detection commonly uses the Limulus amebocyte lysate (LAL) assay or recombinant alternatives to quantify endotoxin levels.

Detection and control strategies emphasize depyrogenation and removal of endotoxins from products. Methods include dry heat sterilization, ultrafiltration, and affinity-based techniques using polymyxin B or other endotoxin-binding agents. Clinically, management of endotoxemia or sepsis follows established sepsis protocols, with supportive care and targeted treatment of the underlying infection.