Abstract
Human neutrophils undergo respiratory burst and generate oxygen metabolites in response to various stimuli. Primary product during this process is superoxide anion. The system responsible for this reaction is located at plasma membrane and is called NADPH oxidase, which means electron transport system receiving electron from NADPH in cytosol and giving it to extracellular oxygen. This enzyme is known to consist of seven protein components, namely, gp 91Phox, p 22Phox, Rap 1 A, p 47Phox, p 67Phox, p 40Phox, Rac 1/2. Protein-protein interaction between these components has been intensively studied and clarified. In regard to the signaling system from plasma membrane receptor for superoxide-producing agonists to NADPH oxidase, one member of mitogen-activated protein kinase family, p 38 seems to play a critical role. On the other hand, various physiological agonists including cytokines are known to prime human neutrophils for enhanced release of superoxide upon stimulation with the second triggering agonists, though the mechanism of priming is still largely unknown, and await future investigation.
