Endotoksinlerin

Endotoxins are toxic components derived from the outer membrane of Gram‑negative bacteria, primarily in the form of lipopolysaccharides (LPS). They are released when the bacterial cell wall is disrupted or during cell lysis, and they can also be secreted in small amounts by some bacterial species. Unlike exotoxins, which are proteins secreted into the environment, endotoxins are integral to the bacterial cell and persist as contaminant after bacterial inactivation.

The lipid A portion of LPS is the biologically active part that triggers the host’s innate immune response. It interacts with Toll‑like receptor 4 complexes and can activate macrophages, leading to the release of inflammatory cytokines, fever, and in severe cases, septic shock. Because their action is largely immune‑mediated, their effects are not dose‑dependent in a traditional way; even minute amounts can induce a potent response.

Medicinal and food‑production facilities routinely test for endotoxins using the Limulus amebocyte lysate (LAL) assay or recombinant factor C assays. Regulatory agencies such as the FDA and European Medicines Agency have stringent limits (typically 0.5 EU/mL) for endotoxin contamination in injectable drugs and vaccines.

In clinical settings, high endotoxin levels are associated with gram‑negative sepsis, a leading cause of ICU mortality. Management includes source control, antimicrobial therapy, and supportive measures; specific endotoxin‑neutralizing agents remain under investigation.

Research on endotoxin adjuvants has explored their use in vaccine formulations, where low, controlled amounts can enhance immune responses. Ongoing studies aim to better understand endotoxin structure‑function relationships and develop more sensitive detection technologies.