Phagocytes ingest foreign organisms and digest them intracellularly. The
pathognes are killed in the phagocytes by production of oxygen and nitric
oxide. The ability of the phagocyte to produce oxygen and nitrogen
metabolites, that are lethal to bacteria is increased by the effects of
cytokines such as interferon gamma, (IFN
) and tumor necrosis factor
alpha, (TNF-
).
Another mechanism that aids in microbial killing is the acidification of lysosomal enzymes after the formation of phagolysosomes.