scholarly journals Functional activity of enucleated human polymorphonuclear leukocytes.

1983 ◽  
Vol 97 (2) ◽  
pp. 368-377 ◽  
Author(s):  
D Roos ◽  
A A Voetman ◽  
L J Meerhof
Keyword(s):  
Plasma Membrane ◽  
Polymorphonuclear Leukocytes ◽  
Cytochalasin B ◽  
Unit Area ◽  
Chemotactic Activity ◽  
Myristate Acetate ◽  
Intact Cells ◽  
Ficoll Gradient ◽  
Pmn Functions ◽  
Human Polymorphonuclear Leukocytes

Enucleated human polymorphonuclear leukocytes (PMN) were prepared by centrifuging isolated, intact PMN over a discontinuous Ficoll gradient that contained 20 microM cytochalasin B. The enucleated cells (PMN cytoplasts) contained about one-third of the plasma membrane and about one-half of the cytoplasm present in intact PMN. The PMN cytoplasts contained no nucleus and hardly any granules. The volume of the PMN cytoplasts was about one-fourth of that of the original PMN. Greater than 90% of the PMN cytoplasts had an "outside-out" topography of the plasma membrane. Cytoplasts prepared from resting PMN did not generate superoxide radicals (O2-) or hydrogen peroxide. PMN cytoplasts incubated with opsonized zymosan particles or phorbol-myristate acetate induced a respiratory burst that was qualitatively (O2 consumption, O2- and H2O2 generation) and quantitatively (per unit area of plasma membrane) comparable with that of intact, stimulated PMN. Moreover, at low ratios of bacteria/cells, PMN cytoplasts ingested opsonized Staphylococcus aureus bacteria as well as did intact PMN. At higher ratios, the cytoplasts phagocytosed less well. The killing of these bacteria by PMN cytoplasts was slower than by intact cells. The chemotactic activity of PMN cytoplasts was very low. These results indicate that the PMN apparatus for phagocytosis, generation of bactericidal oxygen compounds, and killing of bacteria, as well as the mechanism for recognizing opsonins and activating PMN functions, are present in the plasma membrane and cytosol of these cells.

scholarly journals Role of microtubule assembly in lysosomal enzyme secretion from human polymorphonuclear leukocytes. A reevaluation.

1977 ◽  
Vol 73 (1) ◽  
pp. 242-256 ◽  
Author(s):  
S Hoffstein ◽  
I M Goldstein ◽  
G Weissmann
Keyword(s):  
Plasma Membrane ◽  
Dose Response ◽  
Lysosomal Enzyme ◽  
Polymorphonuclear Leukocytes ◽  
Cytochalasin B ◽  
Microtubule Assembly ◽  
Enzyme Release ◽  
Thin Sections ◽  
Human Polymorphonuclear Leukocytes ◽  
In Cells

The dose-related inhibition by colchicine of both lysosomal enzyme release and microtubule assembly was studied in human polymorphonuclear leukocytes (PMN) exposed to the nonphagocytic stimulus, zymosan-treated serum (ZTS). Cells were pretreated with colchicine (60 min, 37 degrees C) with or without cytochalasin B (5 microng/ml, 10 min) and then stimulated with ZTS (10%). Microtubule numbers in both cytochalasin B-treated and untreated PMN were increased by stimulation and depressed below resting levels in a dose-response fashion by colchicine concentrations above 10(-7) M. These concentrations also inhibited enzyme release in a dose-response fashion although the inhibition of microtubule assembly was proportionately greater than the inhibition of enzyme release. Other aspects of PMN morphology were affected by colchicine. Cytochalasin B-treated PMN were rounded, and in thin sections the retracted plasma membrane appeared as invaginations oriented toward centrally located centrioles. Membrane invaginations were restricted to the cell periphery in cells treated with inhibitory concentrations of colchicine, and the centrioles and Golgi apparatus were displaced from their usual position. After stimulation and subsequent degranulation, the size and number of membrane invaginations greatly increased. They remained peripheral in cells pretreated with greater than 10(-7) M colchicine but were numerous in the pericentriolar region in cells treated with less than 10(-7) M. Similarly, untreated PMN that were permitted to phagocytose immune precipitates had many phagosomes adjacent to the centriole. After colchicine treatment, phagosomes were distributed randomly, without any preferential association with the centrioles. These data suggest that microtubules are involved in maintaining the internal organization of cells and the topologic relationships between organelles and the plasma membrane.

scholarly journals Effects of quercetin on magnesium-dependent adenosine triphosphatase and the metabolism of human polymorphonuclear leukocytes

Blood ◽  
1981 ◽  
Vol 57 (3) ◽  
pp. 561-566 ◽  
Author(s):  
GD Long ◽  
LR DeChatelet ◽  
JT O'Flaherty ◽  
CE McCall ◽  
DA Bass ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Cell Membrane ◽  
Polymorphonuclear Leukocytes ◽  
Adenosine Triphosphatase ◽  
Glucose Oxidation ◽  
Myristate Acetate ◽  
Respiratory Burst Activity ◽  
Intact Cells ◽  
Human Polymorphonuclear Leukocytes ◽  
Dose Dependent

Abstract The bioflavinoid quercetin was found to exert at least three separate effects on human polymorphonuclear leukocytes. (1) Concentrations of approximately 100 microM inhibited the membrane-associated magnesium adenosine triphosphatase by 60%-80% in either broken cell preparations or intact cells. Lineweaver-Burk plots showed the inhibition to be uncompetitive in nature. (2) Similar concentrations of quercetin inhibited respiratory burst activity of the cells as measured by oxygen consumption, glucose oxidation, or iodination of protein. All inhibitions were dose-dependent and were observed with either opsonized zymosan or phorbol myristate acetate as stimulus. (3) Quercetin likewise inhibited the transport of the nonmetabolizable hexose, 3H-2- deoxyglucose. These observations are most consistent with the hypothesis that quercetin exerts a generalized effect at the level of the cell membrane of the neutrophi.

scholarly journals Mechanisms of lysosomal enzyme release from human polymorphonuclear leukocytes. Effects of phorbol myristate acetate.

1975 ◽  
Vol 66 (3) ◽  
pp. 647-652 ◽  
Author(s):  
I M Goldstein ◽  
S T Hoffstein ◽  
G Weissmann
Keyword(s):  
Phorbol Myristate Acetate ◽  
Lysosomal Enzyme ◽  
Polymorphonuclear Leukocytes ◽  
Cytochalasin B ◽  
Enzyme Release ◽  
Myristate Acetate ◽  
Azurophil Granule ◽  
Cytoplasmic Microtubules ◽  
Specific Granule ◽  
Human Polymorphonuclear Leukocytes

PMA enhanced release of the azurophil granule enzyme, beta-glucuronidase, as well as lysozyme, from cytochalasin B-treated PMN's exposed to either zymosan particles or C5a. PMA was active at nanomolar concentrations, was not toxic to the cells, and was most effective when present for brief durations (0-1 min) before exposure of the cells to the stimuli. Beta-glucuronidase was not released in significant amounts from PMN's exposed to PMA alone, in the absence of stimuli such as zymosan or C5a. In contrast, only the specific granule enzyme, lysozyme, was released from unstimulated cells. Electron micrographs of cells exposed to PMA revealed an increase in the number of visible cytoplasmic microtubules as compared to control cells. Enhancement of lysosomal enzyme (beta-glucuronidase) release by PMA appears to be independent of effects on release of specific granule enzymes (lysozyme), but rather is likely due to PMA-induced elevations of cellular cGMP.

scholarly journals Effects of quercetin on magnesium-dependent adenosine triphosphatase and the metabolism of human polymorphonuclear leukocytes

Blood ◽  
1981 ◽  
Vol 57 (3) ◽  
pp. 561-566
Author(s):  
GD Long ◽  
LR DeChatelet ◽  
JT O'Flaherty ◽  
CE McCall ◽  
DA Bass ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Cell Membrane ◽  
Polymorphonuclear Leukocytes ◽  
Adenosine Triphosphatase ◽  
Glucose Oxidation ◽  
Myristate Acetate ◽  
Respiratory Burst Activity ◽  
Intact Cells ◽  
Human Polymorphonuclear Leukocytes ◽  
Dose Dependent

The bioflavinoid quercetin was found to exert at least three separate effects on human polymorphonuclear leukocytes. (1) Concentrations of approximately 100 microM inhibited the membrane-associated magnesium adenosine triphosphatase by 60%-80% in either broken cell preparations or intact cells. Lineweaver-Burk plots showed the inhibition to be uncompetitive in nature. (2) Similar concentrations of quercetin inhibited respiratory burst activity of the cells as measured by oxygen consumption, glucose oxidation, or iodination of protein. All inhibitions were dose-dependent and were observed with either opsonized zymosan or phorbol myristate acetate as stimulus. (3) Quercetin likewise inhibited the transport of the nonmetabolizable hexose, 3H-2- deoxyglucose. These observations are most consistent with the hypothesis that quercetin exerts a generalized effect at the level of the cell membrane of the neutrophi.

scholarly journals Chemotactic activity of recombinant human granulocyte colony- stimulating factor

Blood ◽  
1988 ◽  
Vol 72 (5) ◽  
pp. 1456-1460 ◽  
Author(s):  
JM Wang ◽  
ZG Chen ◽  
S Colella ◽  
MA Bonilla ◽  
K Welte ◽  
...  
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Chemotactic Activity ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Migratory Response ◽  
Endotoxin Contamination ◽  
Human Polymorphonuclear Leukocytes ◽  
Stimulating Factor ◽  
Chemotactic Effect ◽  
Granular Lymphocytes

Abstract Recombinant human granulocyte colony-stimulating factor (rhG-CSF) induced migration across polycarbonate filters of human polymorphonuclear leukocytes (PMN). rhG-CSF was active in inducing PMN migration at concentrations greater than or equal to 10 to 100 U/mL (7 to 70 ng/mL). rhG-CSF did not contain appreciable levels of endotoxin contamination as assessed by Limulus amebocyte assay, and Polymixin B did not affect the chemotactic activity of rhG-CSF. A monoclonal anti-G- CSF antibody blocked the induction of migration by G-CSF, thus establishing that the cytokine was responsible for the activity of the recombinant preparation. Checkerboard analysis was performed by seeding different concentrations of G-CSF above and/or below the filter and revealed that the migratory response to this cytokine was best observed in the presence of a positive concentration gradient between the lower and upper compartments of the chamber, thus indicating an actual chemotactic effect. When different migrating cells were examined, rhG- CSF was inactive on large granular lymphocytes and endothelial cells under conditions in which appropriate reference attractants were active. In contrast, rhG-CSF elicited a chemotactic response in monocytes inhibited by specific antibody. Thus, G-CSF is a chemotactic signal for phagocytes. This cytokine, when produced at inflammatory sites, may contribute to the recruitment of phagocytes from the blood compartment to amplify resistance against certain noxious agents.

scholarly journals Prevention of degradation of human polymorphonuclear leukocyte proteins by diisopropylfluorophosphate

Blood ◽  
1980 ◽  
Vol 56 (3) ◽  
pp. 442-447 ◽  
Author(s):  
PC Amrein ◽  
TP Stossel
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Actin Binding ◽  
Intact Cells ◽  
Homogenization Treatment ◽  
Human Polymorphonuclear Leukocyte ◽  
Correlating Functions ◽  
Alpha 1 Antitrypsin ◽  
Human Polymorphonuclear Leukocytes ◽  
Neutral Proteases

Abstract Proteases can complicate the characterization of proteins from cells, especially human polymorphonuclear leukocytes (PMN), which contain abundant neutral proteases. We tested the ability of agents to inhibit proteolysis, with special reference to the subunit polypeptides of the contractile proteins actin, myosin, and actin-binding protein (ABP). Phenylmethylsulfonyl fluoride (PMSF), O-phenanthroline, EGTA, EDTA, N- ethylmaleimide, alone or in combinations, failed to prevent extensive proteolysis of the PMN proteins during solubilization of cells with dodecyl sulfate. These inhibitors and also alpha-1-antitrypsin and soybean trypsin inhibitor similarly could not prevent proteolysis during homogenization of cells in cold isosomolar sucrose. Treatment of PMN with greater than or equal to mM diisopropylfluorophosphate (DFP) prior to solubilization or homogenization markedly inhibited proteolysis. PMSF and DFP were equally effective in inhibiting proteolysis in PMN extracts, suggesting that the efficacy of DFP may result from its permeation of intact cells and granules before barriers are disrupted by detergents or homogenization. Treatment of PMN with DFP under conditions inhibiting proteolysis did not affect their rate of phagocytosis. We recommend the use of DFP in future studies correlating functions and protein structure of PMN.

Suppressive action of cobalt on exocytosis and respiratory burst in neutrophils

1989 ◽  
Vol 257 (5) ◽  
pp. C859-C864 ◽  
Author(s):  
J. G. Elferink ◽  
M. Deierkauf
Keyword(s):  
Plasma Membrane ◽  
Phorbol Myristate Acetate ◽  
Respiratory Burst ◽  
Cytochalasin B ◽  
Superoxide Production ◽  
Co2 Activation ◽  
Chemotactic Peptide ◽  
Myristate Acetate ◽  
Intracellular Target ◽  
Suppressive Action

Activation of exocytosis and respiratory burst in rabbit neutrophils by the chemotactic peptide fMet-Leu-Phe is inhibited by Co2+. Inhibition is antagonized by extracellular Ca2+ and is dependent on the time of preincubation of cells with Co2+ before addition of activator. Co2+ inhibits the enhancement of 45Ca association that occurs during activation with fMet-Leu-Phe. Interference with Ca2+ translocation across the plasma membrane by Co2+ is probably not the cause of inhibition of neutrophil activation, because activation in the absence of extracellular Ca2+ is inhibited by Co2+. Activation of neutrophils by phorbol myristate acetate is inhibited at higher Co2+ concentrations than activation by fMet-Leu-Phe. Inhibition of the superoxide production by Co2+ occurs both in the presence or in the absence of cytochalasin B. Fluorescence of neutrophils loaded with quin2 is diminished by Co2+, indicating that Co2+ had entered into the cytoplasm. The results are compatible with the view that Co2+ inhibits exocytosis and respiratory burst in neutrophils by an interaction with a Ca2+-dependent intracellular target.

scholarly journals Inactivation of α2-Macroglobulin by Activated Human Polymorphonuclear Leukocytes

1994 ◽  
Vol 3 (2) ◽  
pp. 117-123 ◽  
Author(s):  
G. Deby-Dupont ◽  
J.-L. Croisier ◽  
G. Camus ◽  
D. Brumioul ◽  
M. Mathy-Hartert ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Proteolytic Activity ◽  
Polymorphonuclear Leukocytes ◽  
Cytochalasin B ◽  
Hypochlorous Acid ◽  
Myeloperoxidase Activity ◽  
Trypsin Activity ◽  
Α2 Macroglobulin ◽  
Human Polymorphonuclear Leukocytes

The proteolytic activity of trypsin releases the dye Remazol Brilliant Blue from its high molecular weight substrate, the skin powder (Hide Powder Azure, Sigma), with an increase in absorbance at 595 nm. Active α2- macroglobulin (80 μg/ml) totally inhibits the proteolytic activity of trypsin (14 μg/ml) by trapping this protease. But after a 20 min incubation of α2-macroglobulin at 37°C with 2 × 106human polymorphonuclear leukocytes activated by N-formyl-L-methionyl-L-leucyl-L-phenylalanine (10−7M) and cytochalasin B (10−8M), 100% of trypsin activity was recovered, indicating a total inactivation of α2-macroglobuHn. Incubation with granulocyte myeloperoxidase also inactivates α2-macroglobulin. Hypochlorous acid, a by-product of myeloperoxidase activity, at a concentration of 10−7M also inactivates α2-macroglobulin, which indicates that an important cause of α2-macroglobulin inactivation by activated polymorphonuclear leukocytes could be the activity of myeloperoxidase.

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