17] Respiratory burst during phagocytosis: An overview

Abstract

This chapter provides an overview of the respiratory burst during phagocytosis. Granulocytes, some classes of macrophages, and natural killer cells release substantial amounts of superoxide (O 2 – ) and hydrogen peroxide (H 2 O 2 ) when their plasmalemma is perturbed. This response and the concomitant phenomena is termed as the “respiratory burst.” The perturbations induced by physiological processes can be mimicked by certain soluble or “quasi-soluble” agents. Moreover, superoxide and H 2 O 2 , formed on the external surface of the plasmalemma and internal surface of the phagosome, may interact to form hydroxyl radical and perhaps singlet oxygen. The most thoroughly studied cidal system known to function in the phagosome consists of myeloperoxidase, H 2 O 2 , and chloride. This system has been shown in vitro to be effective in killing bacteria, yeast, mycoplasma, viruses, and tumor cells. The complex nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity consists of at least two components—namely, a flavoprotein and a b -cytochrome with a low midpoint potential.