ABSTRACT
Phagocytes (neutrophils, monocytes, macrophages, eosinophils), which constitute a front-line of the body’s defense mechanisms against invading microbial pathogens, generate reactive oxygen species (ROS) as one of their instruments for killing foreign organisms. Neutrophils are the first cells to invade a site of inflammation following infection. Upon stimulation with both soluble and particulate matter, the neutrophil oxidative metabolism is activated resulting in a respiratory burst accompanied by a reduction of molecular oxygen to superoxide via a special electron transport system (NADPH-oxidase). Superoxide radicals form hydrogen peroxide in a dismutation reaction catalyzed by the enzyme superoxide dismutase. Hydrogen peroxide serves as a substrate for the myeloperoxidase reaction, in which a variety of highly toxic metabolites, including hypochlorite, are generated. These ROS have strong microbicidal effects and they are of great importance for the proper functioning of the immune system.
