Respiratory burst is related to:

Neutrophil's cell membrane-bound enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is activated on contact with a pathogen. Activation of NADPH oxidase is associated with a sharp increase in O2 uptake and metabolism in the neutrophil (the respiratory burst) and generation of superoxide (O2-) by the following reaction: The combination of the toxic oxygen metabolites and the proteolytic enzymes from the granules makes the neutrophil a very effective killing machine.