The energy metabolism of the leucocyte. X. Kinetics of oxygen consumption during phagocytosis by polymorphonuclear leucocytes. A photometric method

Oxygen metabolism of phagocytosing human polymorphonuclear leucocytes in diabetes mellitus

Zymosan stimulated oxygen metabolism was investigated in polymorphonuclear leucocytes (PMN) from 6 diabetic patients. Oxygen uptake and superoxide production were continuously measured in the presence of autologous or control serum and non-opsonized zymosan, or in the absence of serum and preopsonized zymosan. The only significant impairment in the diabetic cells studied was a lower oxygen uptake in the presence of autologous serum. This defect was normalized by addition of control serum or by omitting the serum and stimulating with opsonized zymosan. In the absence of serum, the oxygen consumption was markedly diminished in only one subject, whereas two subjects showed a decrease of superoxide production in the presence of control serum. An inverse correlation between fasting glucose concentration and oxygen uptake could be demonstrated. However, exposure of normal PMN to hyperglycemic glucose concentration in vitro did not significantly alter their oxygen metabolism, suggesting that glucose alone could not be the only factor responsible for the impaired oxygen consumption in diabetic cells.

The use of luminous bacteria for determination of phagocytosis

The existing methods for phagocytosis evaluation are inadequate for assessing all the real events occurring during phagocytosis, or for continuously following the kinetics of the process. Our purpose is to establish the use of luminous bacteria as an object for phagocytosis. The bioluminescence test offers an easy and simple method to determine the kinetics of phagocytosis by following the luminescence of the bacteria. The terrestrial luminous bacteria Vibrio cholerae var. albensis are readily phagocytosed by polymorphonuclear (PMN) cells. The correlation coefficient between the decrease in luminescence and the decrease in viable count is 0.999. The rate of decrease in luminescence and the residual level of luminescence after 60 min of phagocytosis are proportional to the rate of increase in phagocytosis induced chemiluminescence, and to its maximal level, respectively. Opsonization requirements are comparable in both tests. Different inhibitors of the phagocytosis process caused similar changes in the rates of the bio- and chemiluminescence (correlation coefficient 0.974), and in the luminescence maximal level (correlation coefficient 0.804). The validity of the bioluminescence assay being proved, it is suggested as an alternative assay for phagocytosis assessment.

Partial myeloperoxidase deficiency in preleukemia

In seven subjects with partial and apparently acquired form of myeloperoxidase (MPO) deficiency, some functional properties of neutrophils (PMNs) were studied. Five patients suffered from preleukemia, one from diabetes mellitus and one from carcinoma of the breast with bone marrow metastases. Intracellular bactericidal activity, oxygen consumption and superoxide radical production were within normal limits. In three patients with preleukemia, the serum opsonic activity was markedly reduced (less than m-3SD) in an autologous system, but normal in the presence of pooled normal serum. Decreased opsonic activity was also found when these patient's sera were assayed in the presence of normal PMNs. Since the levels of IgG and C3 were comparable in the patients' sera and the pooled serum, a deficiency of another unknown opsonin or the presence of an opsonization inhibitor has to be postulated. The partial MPO defect apparently doesn't decrease the intracellular killing of Staphylococcus aureus by PMNs. The known susceptibility to bacterial infections in preleukemia may be explained by the reduction of serum opsonization conducing to a secondary decrease of the ingestion and killing of bacteria by the PMNs.

Opsonic activity against zymosan of normal human serum of different blood types

Serum opsonic activity against zymosan was found to be decreased more markedly in highly diluted O type serum than in the other 3 types, among which no difference was noted. Heat-killed bacteria were equally well opsonized with any type of serum. This peculiar activity of O type serum against zymosan was not affected by the removal of isohemagglutinins. No inhibitory activity was demonstrable in O type serum.