Phagocytosing human neutrophils inactivate their own granular enzymes

During phagocytosis, neutrophils generate reactive oxygen metabolites and release lysosomal enzymes into the extracellular medium. We have investigated the possibility that these enzyme are inactivated by the oxygen compounds. Phagocytosing neutrophils from 12 patients with chronic granulomatous disease, which do not generate these oxygen metabolites, released two to three times more activity of lysozyme and beta-glucuronidase than did normal neutrophils. This difference proved to be due to a decrease of approximately 20% of the total activity of these enzymes in normal neutrophils, but not in neutrophils of patients with chronic granulomatous disease. This inactivation of enzymes took place during phagocytosis of opsonized zymosan particles as well as during stimulation of normal cells with phorbol myristate acetate. The inactivation was not due to formation of inhibitors. The lysosomal enzymes were not activated when the neutrophils were stimulated under anaerobic conditions. Addition of catalase, superoxide dismutase, or albumin gave no protection against the oxidative damage; reduced glutathione gave partial protection. The oxidative inactivation was more pronounced in the presence of azide. Measurement of the activity and the amount of protein of acid alpha-glucosidase in the cells showed that the specific activity of this enzyme decreased by approximately 50% during 30 min of phagocytosis. This indicates that the inactivation of the lysosomal enzymes takes place in the phagolysosomes, before the enzymes have leaked into the extracellular medium.

Monocyte alpha-naphtyl esterase deficiency in chronic granulomatous disease

Monocytes from five unrelated children (four boys and a girl) with chronic granulomatous disease were studied for their ability to reduce nitroblue tetrazolium dye after stimulation with zymosan, and for their alpha-naphtyl butyrate esterase activity. As expected, monocytes ingested zymosan particles but failed to reduce nitroblue tetrazolium dye. However, monocytes from two boys out of the five patients were alpha-naphtyl butyrate esterase-negative, whereas both their neutrophils and monocytes were positive for granular naphtol AS-D esterase activity.

Utilization of liposomes for correction of the metabolic and bactericidal deficiencies in chronic granulomatous disease

IgG-coated liposomes containing glucose oxidase (GO) in order to provide a means of generating H2O2 were prepared. Leukocytes from patients with chronic granulomatous disease (CGD) which are lacking a means of generating H2O2, ingested the IgG-coated liposomes and metabolic oxidative deficiencies of glucose-1-14C oxidation and iodination were normalized. Both of these activities have been shown to depend upon the availability of H2O2 within polymorphonuclear leukocytes. Improvement in the capacity to kill Staphylococcus aureus by chronic granulomatous disease leukocytes were observed under similar conditions. Thus, it is possible to restore the oxidative metabolic capacities to CGD leukocytes by the introduction of glucose oxidase containing liposomes to these cells.

Comparison of myeloperoxidase activity in leukocytes from normal subjects and patients with chronic granulomatous disease

A study was undertaken to compare myeloperoxidase (MPO) activity in leukocytes from normal subjects and those with chronic granulomatous disease (CGD) and to eliminate further consideration of MPO as the oxidase responsible for the post-phagocytic respiratory burst and subsequent oxidase microbicidal sequence lacking in leukocytes from patients with CGD. With use of granule fractions isolated from a number of samples, MPO activity in several MPO-mediated biochemical systems (peroxidase assays, protein iodination, and amino acid decarboxylation) was measured. No difference was demonstrated between granule fraction preparations from normal subjects and those with CGD. These data show that MPO activity is normal in CGD leukocytes and are inconsistent with a role for MPO in initiating the post-phagocytic respiratory burst.

Analytical subcellular fractionation of neutrophils from patients with chronic granulomatous disease. Demonstration of the enzyme defect in four cases

Analytical subcellular fractionation studies were performed on neutrophils from five patients, including two females, with chronic granulomatous disease. The density distribution and marker enzyme activities of the principal subcellular organelles in unstimulated cells were similar to those in unstimulated neutrophils from control subjects. NADH dependent reduction of nitroblue tetrazolium was measured in four of the patients including one female. In homogenates of whole cells the specific activity of this enzyme expressed as milliUnits/mg protein was lower in the patients than in the controls, but the difference was not statistically significant. There was however a highly significant difference between the specific activities of this enzyme in the plasma membrane fractions isolated from neutrophils of the four patients and the three controls. These findings suggest that the primary microbicidal oxidase of neutrophils, defective function of which manifests as the syndrome of chronic granulomatous disease, is a plasma membrane NADH oxidoreductase.

Multiple leukocyte abnormalities in chronic granulomatous disease: a familial study

A variety of leukocyte enzyme activities were studied in an 11-year-old female with chronic granulomatous disease (CGD) and several members of her family. Leukocyte glucose-6-phosphate dehydrogenase (G-6-PD) activity was 17 nmol/min/mg protein in the patient; two brothers with symptoms of recurrent bacterial infections have G-6-PD activities of 58 and 37 nmol/min/mg protein; the activites of this enzyme in both parents, maternal grandmother, and one additional brother were within normal limits. Storage at 4 degrees or heating at 37 degrees over a 120-min period revealed a marked lability of G-6-PD activity in the patient's cells which could not be stabilized by the addition of NADP and 2-mercaptoethanol; this lability was not seen in other family members tested. Activities of leukocyte glutathione reductase were reduced in both parents and the two affected male siblings with values of 18, 23, 23, and 24 nmol/min/mg protein, respectively. Activities of leukocyte glutathione peroxidase were reduced in all of the immediate family members tested, with values ranging from 11.2 to 43 nmol/min/mg protein; the activity of this enzyme in the patient was 38.5. Leukocyte NADP content in the patient, father, and two affected male siblings were 16.5, 23.4, 22.2, and 28.2 nmol/15 min/10(7) leukocytes, respectively.

Deficiency of NADPH oxidase activity in chronic granulomatous disease

NADPH oxidase activity was examined in paired 27,000 x g granule fractions isolated from normal polymorphonuclear leukocytes from patients with chronic granulomatous disease. At 0.17 mM NADPH, the oxidase activity was not measurable in normal resting cells but was activated by phagocytosis. This activation was absent in CGD cells. At higher levels of NADPH, activity was present in cells from patients with CGD, although it was lower than normal, and no difference in activity was found between resting and phagocytizing cells. Granule fractions from phagocytizing normal cells exhibited higher than granule fractions from resting normal cells at all levels of NADPH. These results suggest that NADPH oxidase activity is defective in chronic granulomatous disease, and further that the defect is not the absence of the enzyme but rather a failure to activate it.

Comparison of NADH and NADPH oxidase activities in granules isolated from human polymorphonuclear leukocytes with a fluorometric assay

A fluormetric method for the determination of pyridine nucleotides has been adapted for use in studying the reduced pyridine nucleotide oxidases in human polymorphonuclear leukocytes. In the presence of strong base the oxidized forms of the pyridine nucleotides form a highly fluorescent product. The small amounts of NAD(P) formed by the oxidase reactions can be determined with great sensitivity. This method has been compared to the radioisotopic assay for NADPH oxidation. Both methods gave essentially the same results in terms of nanomoles NADP produced by control, resting, and phagocytizing samples. Both NADPH and NADH oxidase activities were insensitive to cyanide. NADPH oxidation had a pH optimum of 5.5, while that for NADH appeared to be 6.0. Granules isolated from phagocytizing cells routinely showed more activity toward both substrates (two to threefold) than granules from resting cells. Both activities were located primarily in a granule fraction prepared by differential centrifugation. Oxidation of NADPH was routinely four to five times that of NADH at all except very high substrate levels. Measurable NADH oxidation was rarely seen below 0.80 mM NADH, while NADPH oxidation was easily measurable at 0.20 mM. One patient with chronic granulomatous disease was studied. At low substrate levels, there was no activity toward either substrate in granules isolated from either resting or phagocytizing cells of this patient, while granules isolated from normal control cells showed substantial activity at these substrate levels. Purification of the activities had been initiated with linear sucrose gradients. Both activities co-sediment to a very dense region of the gradient, a region different from that in which membrane or azurophil granules usually equilibrate. The peak gradient fractions show a 10-30-fold increase in specific activity over comparable granule fractions. These data suggest that the oxidase activities are associated with one enzyme that has different affinities for the two substrates ans support the contention that the oxidation of NADPH is responsible for the metabolic burst accompanying phagocytosis in human PMNL.

Characterisation of the enzyme defect in chronic granulomatous disease

Strikingly reduced activity of an enzyme, normally located in the plasma membrane of human neutrophils, has been demonstrated in a male patient with chronic granulomatous disease (C.G.D.). The subcellular distribution of N.A.D.H.-dependent reduction of nitroblue tetrazolium (N.B.T.) was determined in neutrophils because reduction of this dye by these patients is grossly impaired. Assayed at high concentrations of N.A.D.H. (1 mmol/1), N.B.T. is reduced by enzymes in the cytosol and mitochondria in addition to the plasma membrane by both normal and C.G.D. cells--properties which previously obscured the identity and location of this enzyme. At a more physiological concentration of N.A.D.H. (25 mumol/1), reduction of the dye by the plasma membrane, the principal site of N.B.T. reduction by normal neutrophils, was absent in the patient with C.G.D. It is suggested that absence or imperfect function of this reductase enzyme is the primary lesion in this disease.