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Z A COHN

Publications and source records attributed to Z A COHN.

At least 19 recordsLinked to original sources
PubMed1965

THE IN VITRO DIFFERENTIATION OF MONONUCLEAR PHAGOCYTES. II. THE INFLUENCE OF SERUM ON GRANULE FORMATION, HYDROLASE PRODUCTION, AND PINOCYTOSIS.

The concentration of newborn calf serum in the medium has marked effects on the morphological and biochemical properties of mouse mononuclear phagocytes. At a low serum concentration, the cells developed small numbers of tiny cytoplasmic granules and little or no increase in acid phosphatase, cathepsin, and beta-glucuronidase. As the serum concentration was raised, granules were formed at a more rapid rate and were larger in size. The rate of production and total amount of three hydrolytic enzymes was increased at higher levels of serum. Observations on living cells indicated that the phase-dense granules which accumulated in the perinuclear region were derived from pinocytic vesicles. These clear vesicles fused and migrated to the centrosphere where they underwent a gradual increase in phase density and reacted positively for acid phosphatase. A microscopic technique was described for the evaluation of the pinocytic process. When this method was employed, the rate of pinocytosis increased curvilinearly with elevations in the calf serum concentration of the medium. The comparative influence of bovine, horse, and rabbit serum on mouse cells was evaluated. It is suggested that pinocytosis is a major regulator of granule formation and hydrolytic enzyme production by the mouse macrophage.

Acid Phosphatase↗
PubMed1965

THE IN VITRO DIFFERENTIATION OF MONONUCLEAR PHAGOCYTES. I. THE INFLUENCE OF INHIBITORS AND THE RESULTS OF AUTORADIOGRAPHY.

The influence of selected inhibitors of protein synthesis on the in vitro differentiation of mouse mononuclear phagocytes has been investigated. DL-p-Fluorophenylalanine at concentrations of 250 microg/ml inhibits the formation of three lysosomal hydrolases, cytochemically demonstrable acid phosphatase and osmiophilic, phase-dense granules. These effects occur in the absence of cell death and are reversed by L-phenylalanine. Puromycin at concentrations of 0.2 to 0.4 microg/ml has a similar effect on both the morphology and biochemistry of cell maturation. Colchicine at a concentration of 0.05 microg/ml inhibits the growth in cell diameter and has less of an effect on enzyme production. Cells exposed to leucine-H(3) for 2 to 3 minutes exhibit the localization of grains in the perinuclear-dense granule region. After an exposure of 60 minutes a similar localization is evident but with a correspondingly greater number of grains. A similar localization of grains occurs when choline-methyl-H(3) is employed as a tracer. The data suggest the storage of newly formed protein and possibly phospholipid in the centrosphere region.

Acid Phosphatase↗
PubMed1965

THE DIFFERENTIATION OF MONONUCLEAR PHAGOCYTES. MORPHOLOGY, CYTOCHEMISTRY, AND BIOCHEMISTRY.

The in vitro differentiation of homogeneous populations of monocyte-like cells from the unstimulated mouse peritoneal cavity is described. Under the conditions employed, a progressive increase in cell size occurs without significant cell division. This process is characterized morphologically by the accumulation of phase-dense and neutral red-positive granules, mitochondria, and lipid droplets. The phase-dense granules react strongly for acid phosphatase. Biochemical determinations indicate marked increases in the total content and specific activity of acid phosphatase, cathepsin, and beta-glucuronidase. The production of acid phosphatase is more rapid and extensive than that of the other two hydrolases. From these data it appears that the conversion of a monocyte-like cell to a mature macrophage is accompanied by the formation of increased numbers of lysosome-like cytoplasmic organelles. Mouse peritoneal phagocytes stimulated in vivo with a bacterial lipopolysaccharide undergo a similar series of morphological and biochemical events.

Acid Phosphatase↗
PubMed1964

THE FATE OF BACTERIA WITHIN PHAGOCYTIC CELLS. 3. DESTRUCTION OF AN ESCHERICHIA COLI AGGLUTINOGEN WITHIN POLYMORPHONUCLEAR LEUCOCYTES AND MACROPHAGES.

The fate of a heat-stable Escherichia coli agglutinogen within three types of rabbit phagocytic cells was examined. A system is described whereby quantitative ingestion of viable E. coli by suspensions of PMN leucocytes, BCG-induced alveolar macrophages, and oil-induced peritoneal macrophages took place in vitro. After various periods of intracellular residence aliquots were injected intraperitoneally into NCS mice and the resulting agglutinins assayed. The loss of immunogenicity within phagocytes was estimated by comparison with a dose-response titration prepared with bacteria alone. Under these conditions no increase in immunogenic mass occurred in vivo or in vitro when viable organisms were employed. PMN leucocytes and alveolar macrophages destroyed the majority of the immunogen within 2 hours of intracellular residence. In contrast, the immunogenicity of E. coli was maintained within peritoneal macrophages for periods up to 5 hours. The use of heat-killed bacilli or specific immune serum did not significantly influence the intracellular fate of the immunogen. Residual immunogenicity was associated with a particle having the same centrifugal properties as the intact organism and essentially none was released in a soluble form. Intracellular residence within phagocytic cells did not influence the resulting temporal sequence of antibody formation nor the proportions of mercaptoethanol-sensitive and resistant immune globulins.

Agglutination↗
PubMed1963

THE PARTICULATE HYDROLASES OF MACROPHAGES. II. BIOCHEMICAL AND MORPHOLOGICAL RESPONSE TO PARTICLE INGESTION.

The influence of phagocytosis on the morphological and biochemical properties of macrophage hydrolase-containing granules has been studied in vitro. Following the uptake of large numbers of heat-killed bacteria, an intracellular rearrangement of hydrolytic enzymes occurred. This was associated with the solubilization of 50 to 60 per cent of the total cell content of acid phosphatase, cathepsin, lysozyme, beta glucuronidase, acid ribonuclease, and acid desoxyribonuclease and with a corresponding decrease in granule-bound enzyme. With more prolonged incubation the majority of the soluble intracellular pool of acid ribonuclease and lysozyme was lost to the extracellular medium. No change in the total content of any of the hydrolases was noted during 180 minutes of incubation in vitro. The morphological fate of the granules was studied by a histochemical method for acid phosphatase. After the phagocytosis of yeast cell walls there was a disappearance of acid phosphatase-positive granules and an accumulation of reaction product about the ingested particle. Experiments employing macrophages which were supravitally stained with neutral red also demonstrated the loss of neutral red-positive granules and the accumulation of the dye about the yeast cell walls. These results strongly suggest that lysis of macrophage granules occurs following phagocytosis and that a portion of the granule contents are then resegregated within the newly formed phagocytic vacuole.

Acid Phosphatase↗
PubMed1963

THE PARTICULATE HYDROLASES OF MACROPHAGES. I. COMPARATIVE ENZYMOLOGY, ISOLATION, AND PROPERTIES.

The contents of selected hydrolytic enzymes of oil-induced peritoneal, normal alveolar, and BCG-induced alveolar macrophages have been studied. On a per cell or nitrogen basis the normal alveolar cells contained considerably more acid phosphatase, cathepsin, acid ribonuclease, lysozyme, and lipase than peritoneal cells. The BCG-induced alveolar macrophage exhibited increased levels of acid phosphatase, lysozyme, and lipase as compared to alveolar macrophages from unstimulated rabbits. The morphological differences between these cells was discussed and electron micrographs of the BCG-induced macrophage presented. Fractionation of the BCG-induced macrophage by differential centrifugation showed that 60 to 80 per cent of the total cell content of acid phosphatase, cathepsin, beta glucuronidase, acid ribonuclease, acid deoxyribonuclease, aryl sulfatase, lysozyme, and lipase were localized in a postnuclear fraction which sedimented at 15,000 g. This fraction also contained the majority of the mitochondria as evidenced by its content of cytochrome oxidase. Non-specific esterase was not localized to this fraction. A separation of the hydrolase-containing particles and mitochondria was achieved by isopycnic sucrose gradient centrifugation. Under the conditions employed, the mitochondria distributed at densities of 1.19 to 1.20, whereas the hydrolase particles sedimented to a density of 1.26 to 1.27. Each of the hydrolases including acid phosphatase, beta glucuronidase, cathepsin, lysozyme, and acid ribonuclease exhibited maximum activities in the same gradient fraction. The isolated granules exhibited enzymatic latency, and activation could be achieved by cycles of freezing and thawing or surface active agents. The majority of each of the hydrolytic enzymes could be liberated in a non-particulate form by mechanical trauma. Macrophages which had been stained supravitally with neutral red were fractionated by differential and gradient centrifugation. More than 70 per cent of the dye could be recovered in the particulate hydrolase fraction. The isolated, stained granules resembled those seen in the intact cell.

Acid Phosphatase↗
PubMed1963

The fate of bacteria within phagocytic cells. I. The degradation of isotopically labeled bacteria by polymorphonuclear leucocytes and macrophages.

The intraleucocytic fate of a variety of P(32)- and C(14)-labeled bacteria has been studied in both polymorphonuclear leucocytes and macrophages. Both cell types brought about extensive degradation of bacterial lipids, nucleic acids, and proteins. Intracellular breakdown was primarily dependant upon the composition of the ingested particle rather than on the type or source of the phagocyte. Evidence is presented for the reincorporation of bacterial constituents into leucocyte lipid. More than 50 per cent of the acid-soluble degradation products of P(32)-labeled bacteria appear as inorganic phosphate. Bacterial RNA is degraded more readily than DNA. Following phagocytosis, labeled bacteria lose their pool of small molecular weight intermediates. This is followed by the degradation of acid-insoluble constituents. The majority of bacterial breakdown products are then excreted by the leucocyte and appear in the medium. Heat-killed bacteria were more readily broken down than viable organisms. Only small amounts of C(14)-labeled bacteria were completely oxidized by leucocytic enzymes to C(14)O(2). Acid extracts of polymorphonuclear leucocyte granules, which were highly bactericidal, liberated the acid-soluble constituents of labeled bacteria but did not significantly degrade bacterial macromolecules.

Bacteria↗
PubMed1963

The fate of bacteria within phagocytic cells. II. The modification of intracellular degradation.

The influence of immune serum, PMN leucocytes, and macrophages from immunized animals and metabolic inhibitors on the intraphagocytic degradation of isotopically labeled bacteria has been evaluated. Immune serum specifically delayed the degradation of a variety of P(32)- and C(14)-labeled organisms within both types of phagocytic cells. The active principle in immune serum was found to be a globulin which could be removed by adsorption with the homologous organism. The inhibiting action of immune serum was thought to be related to its combination with the bacterial surface and the subsequent temporary protection of the bacteria from leucocyte enzymes. PMN leucocytes and macrophages obtained from immune hosts did not differ from normal cells in their ability to degrade homologous, labeled bacteria. Immune serum had the same inhibiting influence in the presence of "immune" cells as with cells from non-immunized hosts. Iodoacetate, arsenite, and cyanide at concentrations which inhibited the glycolysis and respiration of both PMN leucocytes and macrophages had no influence on the rate of degradation of isotopically labeled bacteria engulfed by these cells. This implied that following the initial phagocytic events, the degradation of bacteria within leucocytes is not dependent upon the major pathways of energy metabolism.

Animals↗
PubMed1960

Degranulation of polymorphonuclear leucocytes following phagocytosis of microorganisms.

A marked reduction in numbers of cytoplasmic granules in rabbit and human polymorphonuclear leucocytes takes place following ingestion of various microorganisms or of a yeast cell wall preparation. The degranulation occurs within 30 minutes of phagocytosis, and is directly related to the quantity of material engulfed. White cells completely degranulated following phagocytosis of large numbers of microorganisms remain viable for at least 1 hour. The granules of polymorphonuclear leucocytes contain the antimicrobial agent, phagocytin, and various digestive enzymes. These substances thus are released into the cytoplasm or into vacuoles following ingestion of foreign material. The granule system and granule lysis mechanism may well play a central role in the primary function of these specialized cells; namely, that of destroying invading microorganisms.

Animals↗