Oxidative burst
The oxidative burst ( Engl. Burst for "onset", "burst" or "burst"), also known as respiratory burst is designated, the release of reactive oxygen species ( "oxygen free radicals") by neutrophils and macrophages in the phagocytosis .
Discovery and description of the oxidative burst
In 1932 Baldrige and Gerard discovered that during phagocytosis the oxygen consumption of the granulocytes increases to 50 to 100 times the value. Associated with oxygen consumption is the gradual development of various reactive oxygen species. The process is catalyzed by the enzyme NADPH oxidase . The granulocytes are activated by a stimulus and the reaction is initiated. With the mediation of NADPH oxidase , the hyperoxide anion O 2 - is generated from oxygen and nicotinamide adenine dinucleotide phosphate (NADPH) . The highly reactive hyperoxide anion itself is the starting product for the synthesis of a number of other reactive oxygen species. For example, disproportionation catalyzed by superoxide dismutase results in the much more stable hydrogen peroxide . As a neutral, water-like molecule, hydrogen peroxide can very easily penetrate cells. The catalytic decomposition of hydrogen peroxide produces the highly reactive hydroxyl radical · OH, which can attack a large number of molecules.
From hydrogen peroxide and the simultaneous presence of oxygen radicals, myeloperoxidase can form the oxidizing agent hypochlorous acid (HClO) from the primary granules of chloride ions .
meaning
With these reactive oxygen species, it is possible for neutrophils and macrophages to digest the intracellular digestion of phagocytosed ("eaten") foreign bodies such as pathogens . These oxidizing agents react, among other things, with proteins , nucleic acids and other cell components of the pathogen. They also deactivate endogenous protease inhibitors that would prevent the breakdown of proteins.
The importance of the oxidative burst for defense is illustrated by the clinical pictures septic granulomatosis and myeloperoxidase defect.
Individual evidence
- ↑ CW Baldrige, RW Gerard: The extra respiration of phagocytosis. In: Am J Physiol , 103/1933, pp. 235-236.
- ↑ a b M. Ludwig: Experimental studies on cell-cell interactions of pulmonary epithelia and granulocytes. , Dissertation, Justus Liebig University Giessen, 2006.
- ↑ BM Babior: NADPH oxidase. In: Curr Opin Immunol , 16/2004, pp. 42-47.
- ↑ F. Chabot et al.: Reactive oxygen species in acute lung injury. In: Eur Respir J , 11/1998, pp. 745-757.
literature
- O. Hauschild: Suitability of lyophilized liposomes containing glucose oxidase for the correction of the NADPH oxidase deficiency in granulocytes. Dissertation, Eberhard-Karls-Universität zu Tübingen, 2003
- MR Gwinn, V. Vallyathan: Respiratory burst: role in signal transduction in alveolar macrophages. In: Journal of Toxicology and Environmental Health - Part B - Critical Reviews . , 9/2006, pp. 27-39.
- EB Thorgersen et al: Oxidative burst in complement deficient patients: Lessons from nature. In: Molecular Immunology , 44/2007, p. 3968.
- N. Noke et al .: The oxidative burst protects plants against pathogen attack: mechanism and role as an emergency signal for plant bio-defense - a review. In: Gene , 179/1996, pp. 45-51.