endotoxin
An endotoxin is a toxic component of the OUTER MEMBRANE of GRAM-NEGATIVE BACTERIA, mainly composed of LIPOPOLYSACCHARIDE (LPS), that can trigger strong IMMUNE RESPONSES and cause INFLAMMATION when released into the body.
Endotoxins are heat-stable BACTERIAL TOXINS that form an integral part of the CELL WALL and OUTER MEMBRANE of GRAM-NEGATIVE BACTERIA. The major endotoxin molecule is LIPOPOLYSACCHARIDE (LPS), which consists of LIPID A, a core polysaccharide, and O ANTIGEN. The LIPID A component is primarily responsible for the toxic effects by activating the INNATE IMMUNE SYSTEM, stimulating MACROPHAGES and other immune cells to release CYTOKINES such as TUMOR NECROSIS FACTOR (TNF) and INTERLEUKINS. Excessive endotoxin exposure can lead to severe INFLAMMATION, FEVER, SEPTIC SHOCK, and MULTIPLE ORGAN FAILURE. Endotoxins differ from EXOTOXINS because they are structural components of bacteria and are mainly released during bacterial destruction or cell breakdown.
An endotoxin is a harmful substance found in some bacteria that can be released when bacteria break apart and may cause fever, inflammation, or serious illness.
• Endotoxins are toxins found inside the outer layer of certain bacteria. • The most important endotoxin is lipopolysaccharide (LPS). • The toxic part of LPS is called Lipid A. • Endotoxins are released when bacterial cells are damaged or destroyed. • They activate the immune system and cause inflammation and fever. • High levels of endotoxin may cause sepsis and septic shock. • Unlike exotoxins, endotoxins are part of the bacterial structure rather than actively secreted.
endotoxin