The phagocyte NADPH oxidase and bacterial infections

Neutrophils play a crucial role in host defense against microbial infections. During phagocytosis of invading bacteria or fungi, the phagocyte NADPH oxidase produces superoxide. The importance of the oxidase is exemplified by the genetic disorder known as chronic granulomatous disease (CGD). The neutrophils of CGD patients cannot produce superoxide, with the result that affected infants and children suffer from severe recurrent bacterial and fungal infections. Staphylococcus aureus and Aspergillus fumigatus often cause life-threatening infections in these patients. The phagocyte NADPH oxidase is composed of the plasma membrane protein (cytochrome b 558) and cytosolic proteins. Cytochrome b 558 is a heterodimer consisting of the gp91 phox and p22 phox . The cytosolic proteins are p47 phox , p67 phox , p40 phox and a small G-protein, Rac. The oxidase is also expressed in peripheral eosinophils, monocytes, B lymphocytes, and several cultured cell lines after differentiation other than neutrophils. Here, we will consider and discuss the oxidase in relation to CGD.