Catalase-dependent peroxidative metabolism in the alveolar macrophage during phagocytosis

A B S T R A C T Bacterial infection may complicate pulmonary oxygen (02) toxicity, and animals exposed to high 02 concentrations show depressed in vivo pulmonary bacterial inactivation. Therefore, in vitro studies were undertaken to define the mechanism by which 02 alters pulmonary antibacterial activity. Normal and BCG pretreated rabbits were exposed to 100% 02 for 24, 48, and 72-h periods. Pulmonary alveolar macrophages (PAM) were obtained from the experimental animals and from nonoxygen exposed controls by bronchopulmonary lavage. 02 exposure did not alter cell yield or morphology. PAMs were suspended in 10% serum-buffer, and phagocytosis of ["C]Staphylococcus aureus 502A and ["C]Pseudomonas aeruginosa was measured. Comparison of the percent uptake of the "Clabeled S. aureus after a 60-min incubation period demonstrated that normal PAMs exposed to 02 for 48 h showed a statistically significant increase in phagocytosis when compared to their controls (43.5 vs. 29.2%). A similar, but smaller, increase was seen after 24-h 02 exposures. 48 and 72-h 02 exposures produced no significant changes in phagocytosis in PAMs from BCG-stimulated rabbits. Normal PAMs also showed an increased phagocytosis of Ps. aeruginosa after 48-h oxygen exposures. No impairment of in vitro bactericidal activity against either S. aureus 502A or Ps. aeruginosa could be demonstrated in PAMs from normal rabbits exposed to 02 for 48 h. These results indicate that the in vitro phagocytic and bactericidal capacity of the rabbit PAM is relatively resistant to the

Section: Resultssupporting

confidence: 70%

Effects of oxygen exposure on in vitro function of pulmonary alveolar macrophages.

Murphey¹,

Hyams²,

Fisher³

et al. 1975

“…bolus (28), as was the case here. Although data bearing on this point are lacking, it seems likely that fixed -phagocytic cells are also able to deiodinate T4 in view of the evidence that T. deiodination may be mediated by a peroxidase-hydrogen peroxide system (29) and that phagocytic cells other than circulating leukocytes, such as peritoneal and alveolar macrophages, also generate increased quantities of hydrogen peroxide during phagocytosis (30,31). Moreover, the increased hepatic uptake of T4 observed in the bacteremic monkeys may have been related to altered Kupffer cell activity in view of the evidence that Kupffer cells may possess a peroxidase-mediated antimicrobial system similar to that found in circulating leukocytes (32).…”

Section: Resultsmentioning

confidence: 99%

Accelerated Cellular Uptake and Metabolism of L-Thyroxine during Acute Salmonella typhimurium Sepsis

DeRubertis¹,

Woeber²

1973

A B S T R A C T The effects of acute Salmonella typhimurium sepsis on the kinetics of peripheral L-thyroxine (T4) distribution and metabolism and on serum total and free T4 concentrations were studied in rhesus monkeys inoculated i.v. with either heat-killed or viable organisms. The rate of disappearance of labeled T4 from serum was increased within 8 h after inoculation of monkeys with either heat-killed or viable Salmonella. The effects of the heat-killed organisms were transient and no longer evident by 16 h postinoculation. The monkeys inoculated with the viable Salmonella experienced a 2-3 day febrile, septic illness that was accompanied by an increase in the absolute rate of T4 disposal. In the infected monkeys, serum total T4 and endogenously labeled protein-bound iodine concentrations fell significantly during the period of acute sepsis and then rose during convalescence to values that exceeded the preinoculation values, suggesting that thyroidal secretion of hormone had increased in response to a primary depletion of the peripheral hormonal pool. Total cellular and hepatic uptakes of T4 were enhanced by 4 h after inoculation of monkeys with either heatkilled or viable Salmonella, but the increase in total cellular uptake persisted for 24 h only in the monkeys inoculated with the viable organisms. These alterations in T4 kinetics could neither be correlated with changes in the binding of T4 in plasma nor attributed to an increase in vascular permeability. Moreover, they could not be ascribed to an in vitro product of bacterial growth, suggesting that the presence of the organisms themselves was required. An acceleration of T4 disappearance was also observed during Escherichia coli and Diplococcus pneumioniae bacteremias. Our findings are Dr. Woeber's present address is the

“…Engulfment of a variety of kinds of particles by alveolar macrophages causes increased oxidation of glucose labeled in the first and sixth carbon positions, presumably reflecting augmentation of Krebs' cycle and hexose monophosphate shunt activity (13,14). Phagocytosis of paraffin oil droplets similarly enhanced the oxidation of glucose-1-'C and glucose-6-14C by alveolar macrophages.…”

Section: Discussionmentioning

confidence: 99%

Isolation and Properties of Phagocytic Vesicles II. ALVEOLAR MACROPHAGES

Stossel¹,

Mason²,

Pollard³

et al. 1972

A B S T R A C T Phagocytic vesicles were obtained by density gradient centrifugation of homogenized rabbit alveolar macrophages that had ingested emulsified paraffin oil contained Oil Red 0. The phagocyte vesicles floated and thereby were separated from the soluble fraction and from other cell components which sedimented. The purity of the isolated vesicles was documented by electron microscopy, chemical and enzyme analysis. The vesicles contained 87% of the cell-associated Oil Red 0, and were essentially free of DNA, RNA, succinic dehydrogenase, and glucose-6-phosphatase. Acid phosphatase, P-glucuronidase, and catalase were transferred from the sedimenting fraction to the phagocytic vesicle fraction during phagocytosis, whereas enzyme activities of the soluble fraction remained unchanged. Half of the catalase of resting macrophages was in the pellet fraction and, compared with acid phosphatase, greater amounts of digitonin were required to release full activity. Such differential latency has been described for enzymes of peroxisomes vs. those of lysosomes. Compared with polymorphonuclear leukocyte vesicles studied previously, phagocytic vesicles of macrophages had more electron-dense material and lower Oil Red O: protein, phospholipid: protein, and enzyme: protein ratios. It is thus probable that secondary lysosomes become part of the macrophage vesicle. When paraffin oil particles, the stimulus for phagocytic vesicle formation, were washed away from the macrophages, acquisition of hydrolases by preformed vesicles Dr. Stossel's present address is Hematology Division,