[Current knowledge of the mechanism of neutrophil granulocyte and macrophage activation for the formation of superoxide anions and of H2O2 and for the causes of defects in the NADPH-oxidase enzyme system involved].

By the binding of activators (f.e. complement factor C5a, leukotriene B4) to receptors of neutrophil granulocytes an activation of a GTP-binding protein is induced, that increases the activity of the phospholipase C in the membrane and thereby the liberation of inositol-1,4,5-phosphate (IP) and of diacylglycerol (DG). The IP effects the liberation of Ca from intracellular stores and an increase in the concentration of Ca-ions in the cytosol. The DG induces an activation of the phosphokinase C near the membrane, that phosphorylates a cytosolic protein, which takes part in the formation of the NADPH-oxidase. The mentioned reactions induce in the membrane the construction of the NADPH-oxidase from a NADPH-binding protein, a flavoprotein, a cytochrome b 558 and from 4 cytosolic proteins. When phagolysosomes are formed, the NADPH-oxidase is part of the membrane, so bactericidal superoxide-anions can be introduced in these. In the chronic granulomatous disease defects in the formation of cytochrome b or of 2 cytosolic proteins exist.