H2O2 release from human granulocytes during phagocytosis. I. Documentation, quantitation, and some regulating factors.
Open Access
- 1 May 1975
- journal article
- research article
- Published by American Society for Clinical Investigation in JCI Insight
- Vol. 55 (5), 945-955
- https://doi.org/10.1172/jci108024
Abstract
The extinction of fluorescence of scopoletin during its oxidation by horseradish peroxidase (HPO) provides a highly sensitive and specific assay for small quantities of peroxide in solution. With this assay, the release of free H2O2 into the extracellular medium by phagocytizing human granulocytes has been documented and quantitated, and some of the regulating factors have been determined. Under basal conditions granulocytes released less than 0.01 nmol/ml of H2O2 (2.5 X 10-6 polymorphonuclear leukocytes/ml). Upon the addition of phagocyte particles (latex, opsonized yeast, or staphylococci), an abrupt increase in extracellular peroxide concentration was observed (greater than 50-fold above basal levels) after latencies as short as 10 s. Release reflected increased intracellular H2O2 production during phagocytosis in that it paralleled the respiratory burst and was absent when phagocytosis was prevented or when cells from patients with chronic granulomatous disease were utilized. Evidence that scpoletin oxidation occurred predominantly in the extracellular medium was obtained by demonstrating a marked inhibition when HPO was omitted from the reaction mixture or when exogenous catalase was added. Similarly, it was found that exogenous serum also inhibited scopoletin oxidation, apparently because of the presence of competing hydrogen donors. H2O2 formation and release were observed at rates which closely paralleled those of phagocytosis. With O2 consumption as an approximate index of H2O2 formation, the fractions released during maximal rates of particle uptake were calculated as follows: for latex, 15.7%; for staphylococci, 10.3%; and for yeast, 4.9%. It is postulated that release is due to diffusion of free H2O2 from an expanded intracellular pool of this substance that develops during phagocytosis. This poos represents tha net of increased synthesis versus catabolism by various enxymatic pathways for H2O2 disposal within the cells. The close relationship between rates of H2O2 formation and rates of phagocytosis by human granulocytes suggests a role for specialized areas of the cell membrane, involved in particle ingestion, in the trigger mechanism for H2O2 synthesis. The consequences of H2O2 release to other cells or organisms in the immediate environment of phagocytizing granulocytes remain to be determined.Keywords
This publication has 23 references indexed in Scilit:
- Myeloperoxidase-Mediated Iodination by Granulocytes INTRACELLULAR SITE OF OPERATION AND SOME REGULATING FACTORSJCI Insight, 1974
- PhagocytosisNew England Journal of Medicine, 1974
- Stimulation of human neutrophil leukocyte aerobic glucose metabolism by purified chemotactic factors.JCI Insight, 1974
- Biological Defense Mechanisms. THE PRODUCTION BY LEUKOCYTES OF SUPEROXIDE, A POTENTIAL BACTERICIDAL AGENTJCI Insight, 1973
- Role of myeloperoxidase-mediated antimicrobial systems in intact leukocytes.1972
- Receptors for human γG Globulin on human neutrophilsJCI Insight, 1970
- Studies on phagocytosis: I. Uptake of radio-iodinated (131I) human serum albumin as a measure of the degree of phagocytosis in vitroExperimental Cell Research, 1969
- RECEPTORS FOR COMPLEMENT ON LEUKOCYTESThe Journal of Experimental Medicine, 1968
- METABOLIC AND MORPHOLOGICAL OBSERVATIONS ON THE EFFECT OF SURFACE-ACTIVE AGENTS ON LEUKOCYTESThe Journal of cell biology, 1967
- The Assay of Catalases and PeroxidasesMethods of biochemical analysis, 1954