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Title: Extracellular proton release by stimulated neutrophils

We have tried to elucidate the mechanism of phagosome acidification in human neutrophils. Assuming that phenomena occurring at the plasma membrane reflect reactions in the phagocytic vacuoles, we have stimulated human neutrophils with agents that induce a ''respiratory burst,'' and we have measured the release of protons into the extracellular medium. Phorbol myristate acetate, N-formyl-methionyl-leucyl-phenylalanine and serum-opsonized zymosan particles each caused a rapid release of protons, concomitant with the increase in oxygen consumption. The stimulated release of protons was strictly coupled to the increase respiration of the cells, because inhibition of the respiration of either anaerobiosis, chlorpromazine, or glycolytic inhibitors also inhibited the release of protons. Also, in the presence of the above-mentioned stimulating agents, neutrophils from three patients with chronic granulomatous disease enhanced neither respiration not proton release. In normal cells, the ratio of deltaH+/-deltaO2 was 1.04 +/- 0.19 (mean +/ SD, n . 13). The mechanism of this proton release is not clear. The amount of lactic and carbonic acid produced by stimulated neutrophils was inadequate to explain the amount of protons released. Perhydroxyl radicals were also ruled out as the source of the protons. Because the cells did not release measurable amounts of phosphate ions, a phosphate-hydroxyl-ionmore » antiport was also excluded. Finally, the lack of any effect of uncouplers renders it unlikely that a respiration-driven proton gradient is built up across the plasma membrane.« less
Authors:
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Publication Date:
OSTI Identifier:
5674691
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Clin. Invest.; (United States); Journal Volume: 68:1
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; NEUTROPHILS; STIMULATION; OXYGEN; METABOLISM; PROTONS; BIOCHEMISTRY; ACETATES; CELL MEMBRANES; HEMIC DISEASES; PATIENTS; RESPIRATION; ZYMOSAN; BARYONS; BIOLOGICAL MATERIALS; BLOOD; BLOOD CELLS; BODY FLUIDS; CARBOXYLIC ACID SALTS; CELL CONSTITUENTS; CHEMISTRY; DISEASES; ELEMENTARY PARTICLES; ELEMENTS; FERMIONS; HADRONS; LEUKOCYTES; MATERIALS; MEMBRANES; NONMETALS; NUCLEONS 550300* -- Cytology