title: Different subcellular localization of cytochrome b and the dormant NADPH-oxidase in neutrophils and macrophages: effect on the production of reactive oxygen species during phagocytosis.
abstract: When neutrophils and macrophages phagocytose a prey, e.g., complement (C3b)-opsonized yeast particles, the oxygen radical generating NADPH-oxidase is activated. In neutrophils, most of the production of oxygen metabolites occurred in an intracellular compartment, possibly in the phagolysosome. In contrast, no intracellular production could be detected in human macrophages. In these cells, the subcellular localization of the superoxide-generating NADPH-oxidase and associated cytochrome b was assessed in intact cells with indirect immunofluorescence and confocal laser scanning microscopy, and with subcellular fractionation, using centrifugation on Percoll density gradients. A dual localization of the cytochrome b as well as the dormant NADPH-oxidase activity in neutrophils was in agreement with earlier immunocytochemical, biochemical, and subcellular fractionation studies. Furthermore, most of the activity was recovered from the specific granules, whereas only a small fraction was retained in the plasma membrane. In contrast, the cytochrome b/NADPH-oxidase activity in macrophages localized primarily in the plasma membrane fraction. We suggest that the macrophages are incapable of producing reactive oxygen species intraphagosomally, due to an absence of a granule-localized pool of the membrane components of the NADPH-oxidase.
authors.affiliation: Department of Medical Microbiology, University of Linköping, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Johansson
authors.forename: A J
authors.initials: AJ
authors.lastname: Jesaitis
authors.forename: H
authors.initials: H
authors.lastname: Lundqvist
authors.forename: K E
authors.initials: KE
authors.lastname: Magnusson
authors.forename: C
authors.initials: C
authors.lastname: Sjölin
authors.forename: A
authors.initials: A
authors.lastname: Karlsson
authors.forename: C
authors.initials: C
authors.lastname: Dahlgren
mesh_terms: D000328:Adult; D002451:Cell Compartmentation; D002458:Cell Fractionation; D003179:Complement C3b; D003573:Cytochrome b Group / Q000302:isolation & purification; D004789:Enzyme Activation; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D008264:Macrophages / Q000502:physiology*; D009247:NADH, NADPH Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D019255:NADPH Oxidases; D009504:Neutrophils / Q000502:physiology*; D009895:Opsonin Proteins; D010587:Phagocytosis / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D003573:Cytochrome b Group; D009895:Opsonin Proteins; D017382:Reactive Oxygen Species; D003179:Complement C3b; D006861:Hydrogen Peroxide; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases