A respiratory burst refers to an increase in the metabolic activity of cells involved in the immune response, specifically, the phagocytes, which are cells that engulf and digest foreign particles. During a respiratory burst, these cells produce and release reactive oxygen species (ROS) and reactive nitrogen species (RNS) as part of their defense mechanism against pathogens. The ROS and RNS are toxic to the pathogens and can also stimulate the production of other immune cells.
Respiratory burst is a part of the oxidative burst, in which cells produce ROS and RNS to defend against pathogens, such as bacteria and viruses. The respiratory burst is mediated by the enzyme NADPH oxidase, which is activated by a variety of stimuli including pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs).
It’s important to note that an excessive or prolonged respiratory burst can also lead to tissue damage and chronic inflammation, therefore it’s a fine balance between producing enough ROS and RNS to eliminate the pathogens without causing harm to the host.