Phagocyte-generated oxygen metabolites and cellular injury.

Phagocytic leukocytes are motile cells capable of inducing damage and lysis of a wide variety of biologic targets. Recent insights into the mechanisms of phagocyte-mediated destruction have derived from the observation that these cells can consume and metabolize oxygen to generate an impressive array of reactive oxygen intermediates. The role of oxygen metabolites in antimicrobial defense mechanisms has been the subject of intensive study, but only recently has attention focused on the potential importance of oxygen in phagocyte-mammalian cell interactions. In this review we will examine evidence obtained in a variety of in vitro model systems demonstrating the ability of intact phagocytes to generate oxygen metabolites capable of destroying normal or neoplastic cells. A basic understanding of the biochemistry of phagocyte-mediated oxygen-dependent events should allow us to elucidate and potentially modulate immunologic defenses against neoplastic invasion, the destruction of normal tissue in pathogenic states, and the course of the inflammatory response. The role of phagocyte-derived oxygen metabolites in microbicidal activity will not be the subject of this report, and the reader is referred to recent comprehensive reviews.