Endotoxin: Structure Source and Effects

Endotoxins are insoluble parts of the bacterial cells able to evoke a typical clinical picture characterizing bacterial infection. Usually, Gram-negative bacteria are a major part of the gut microbiota and are a source of endotoxins, particularly lipopolysaccharide (LPS). Endotoxins can stimulate extracellular and intracellular pathways that lead to the activation of the immune response. Endotoxic shock is a severe, generalized inflammatory response caused by high bloodstream levels of LPS, which plays a very prominent role in its pathogenesis. It is one of the most important pathogen-associated molecular pattern (PAMP). The toll-like receptor (TLR) 4 is the main receptor for LPS and one of the pattern recognition receptors responsible for the early detection of microbes by the innate immune system being involved in a related path of systemic response too.