bluuebunny/crossref_metadata_2025_split huggingface dataset:
Up-Regulation of Gamma Interferon Receptors on the Human Monocytic Cell Line U937 by 1,25-Dihydroxyvitamin D3 and Granulocyte-Macrophage Colony Stimulating Factor
Authors: Zuckerman Steven H , Schreiber Robert D 
Published: January 2018

Abstract
The human monoblast-like cell line U937 can be induced to differentiate by a variety of agents including phorbol esters, retinoic acid, gamma interferon (IFN γ), and 1,25-dihydroxyvitamin D3 (VD3). Increased expression of OKM1 antigen, Fc receptors, and other cell surface antigens occur with the differentiation of this cell line along the macrophage lineage. Whereas 10-8 M VD3 alone induces changes in cell surface antigens, there were no changes in the number or affinity of IFN γ receptors. Incubation of U937 with VD3 and 100 U/ml of granulocyte-macrophage colony-stimulating factor (GM-CSF) resulted in further increases in OKM1 antigen expression and an up-regulation of IFN γ receptors. The number of IFN γ receptors increased between two- and fourfold and was maximal after 48 h incubation with VD3 and GM-CSF. Scatchard analysis revealed a single class of receptors before or after differentiation, although the increase in receptor number was associated with an overall decrease in receptor-binding affinity. Incubation of U937 with VD3 plus GM-CSF and IFN γ resulted in further increases in the density of OKM1 antigen expressed per cell. This increase in OKM1 expression was greater than that observed for U937 incubated with VD3 and GM-CSF or VD3 and IFN γ alone. These results suggest that GM-CSF up-regulates IFN γ receptors on VD3-stimulated U937 and enables these cells to be induced further along the pathway of macrophage differentiation, possibly by subsequent interaction with additional cytokines such as IFN γ.
Merocyanine 540 as a Flow Cytometric Probe of Membrane Lipid Organization in Leukocytes
Authors: McEvoy Leslie , Schlegel Robert A , Williamson Patrick , Del Buono Brian J 
Published: January 2018

Abstract
Merocyanine 540 (MC540) is a fluorescent probe that binds preferentially to membranes with loosely packed lipids. When combined with flow cytometry, it provides a novel methodology for rapidly and quantitatively assessing lipid organization in individual leukocytes. Analysis of cells stained simultaneously with MC540 and 1-[4-trimethylam-moniumphenyl]-6-phenyl-1,3,5-hexatriene, to normalize for surface area, revealed that all leukocytes in peripheral blood bind equivalent amounts of dye per unit surface area. This result indicates that the lipids of the plasma membranes of all types of circulating cells are organized similarly. Upon activation with appropriate stimuli, lymphocytes, monocytes, and neutrophils all bound increased amounts of dye per unit surface area, indicating a change in lipid organization to a less-ordered state. Cells stained with MC540 were sorted on the basis of their fluorescence intensity yielding populations homogeneous with respect to lipid organization. Thus not only can MC540 and flow cytometry be combined for analyzing the organization of lipids in individual leukocytes, but sorted populations can be obtained for further biochemical, structural, and functional analyses.
Superoxide Anion Production in Glass-Adherent Polymorphonuclear Leukocytes and Its Relationship to Calcium Movement
Authors: Rebut-Bonneton C , Bailly S , Pasquier C 
Published: January 2018

Abstract
The production of superoxide anion (O) was measured in relation to 45Ca movement in glass-adherent polymorphonuclear leukocytes (PMNs), and the results were compared with those obtained by ourselves and others on PMNs in suspension. In adherent PMNs, O production stimulated by N-formyl-methionyl-leucyl-phenylalanine (FMLP) was of rapid onset and short duration; this was also true of PMNs in suspension. However, O production was insensitive to the concentration of extracellular calcium. Both in adherent and non-adherent PMNs, O production stimulated with phorbol myristate acetate (PMA) had a latency time and was of long duration. In adherent PMNs, pretreatment with PMA potentiated the FMLP-induced O production by lengthening its duration without changing its initial rate.
In adherent PMNs, (10-10-10-7 M) FMLP induced a fast but transient dose-dependent increase in 45Ca within 1 min, whereas PMA only released 45Ca about 5 min after its addition to the cell culture medium. Pretreatment of PMNs with 10 or 100 ng/ml PMA for 3 min before stimulation by 10-7 M FMLP reduced the 45Ca efflux observed with FMLP alone. We conclude that O production by adherent PMNs cannot simply be related to Ca2+ movement. In comparison with non-adherent cells, adherence seemed to interfere with the characteristics of both calcium and O generation, probably by modifying the cytoskeleton.
Requirements for Histoplasmin Presentation by Accessory Cells to a Histoplasma capsulatum-Reactive T-Cell Line
Authors: Harris Jeffrey E , Deepe George S 
Published: January 2018

Abstract
We examined the pathways involved in presentation of native histoplasmin by adherent splenocytes (as a source of accessory cells) to JC1, a Histoplasma capsulatum-reactive murine T-cell line that is CD4+. JC1 did not respond to accessory cells that had been fixed with paraformaldehyde and then exposed to histoplasmin but did proliferate to antigen-pulsed cells that were subsequently fixed. Accessory cells that were coincubated with histoplasmin and sodium azide or 2-deoxy-D-glucose failed to induce proliferation of JC1. Moreover, accessory cells exposed to the lysosomotropic agents, chloroquine and ammonium chloride, were unable to present antigen. Monensin also inhibited presentation of histoplasmin if added to accessory cells concomitant with antigen. In contrast, accessory cells that had been pulsed with antigen for 2 hr and then exposed to each inhibitor for 2 hr stimulated proliferation of JC1. The antigen-presenting capacity of accessory cells that had been pulsed with histoplasmin for 2 hr was diminished considerably by subsequent treatment with phospholipase A2. Additional studies demonstrated that cerulenin, which depresses posttranslational lipid modification of proteins, abolished presentation of histoplasmin. The reactivity of JC1 was sharply reduced by anti-L3T4 (CD4) or by anti-l-Ab monoclonal antibody. The results not only indicate that presentation of histoplasmin requires active metabolic events within accessory cells, they also delineate the pathways involved in handling this antigen.
Activation and Deactivation of Guinea Pig Peritoneal Eosinophils During Chronic Polymyxin B Stimulation
Authors: Davis W Bruce , Husney Rose M , Mohammed B Selma , Pawluk Lew J , Ackerman G Adolph , Sagone Arthur L 
Published: January 2018

Abstract
Eosinophils exhibit different levels of oxidative metabolism depending on their site of origin and various host factors that may influence metabolism. The present study examined the time course of eosinophil oxidative metabolism in animals undergoing chronic peritoneal stimulation. Eosinophils were purified from the peritoneal exudates of guinea pigs stimulated with weekly polymyxin B and saline peritoneal lavage. 14C-1- and 14C-6-glucose oxidation and H2O2 production were measured at week 0 and at various time points throughout 43 weeks of stimulation. Baseline oxidative metabolism of eosinophils was relatively high throughout the time course, but then declined sharply after 32 weeks. These “deactivated” cells that were recovered after 32 weeks also failed to respond to phorbol myristate acetate (PMA) or opsonized zymosan. Electron microscopy did not reveal significant differences between deactivated eosinophils and cells from earlier time points. These findings document the time course of eosinophil activation and deactivation in this model and suggest that metabolic heterogeneity of eosinophils can occur over time in response to a chronic stimulus.
Modulation of Macrophage Fibronectin Secretion by LPS
Authors: Trotter Kathleen M , Beezhold Donald H , Lause David B 
Published: January 2018

Abstract
The secretion of fibronectin (Fn) by rat peritoneal macrophages was found to be down-regulated by LPS. A sensitive ELISA was used to quantitate both substrate-attached and supernatant Fn. Thiogrycollate-elicited peritoneal exudate cells were observed to release a considerable amount of Fn during the adherence procedure for macrophage purification. After this procedure, macrophage Fn levels peaked within 2 hr and then declined steadily to baseline levels by 96 hr. Fn release by exudate cells during adherence purification was less affected by cycloheximide treatment than was subsequent Fn secretion by purified macrophages. Macrophages elicited with thioglycollate and P. acnes displayed enhanced Fn secretory activity when compared with resident unstimulated cells. Exposure to lipopolysaccharide (LPS) suppressed the levels of immunoreactive Fn in supernatants of elicited cells. This inhibition was shown to be dose-dependent and most significant after 24 hr of incubation. The inclusion of polymyxin B in the culture medium did not reverse the LPS-induced inhibition of Fn production but did prevent LPS stimulation of iterleukin-1 secretion in the macrophage cultures. These observations demonstrate that Fn secretion by macrophages is regulated according to the functional state of the cell.
Quantitative Model of Mononuclear Phagocyte Lineage Proliferation in Murine Bone Marrow
Authors: Novak J P , Skamene E , Gervais F 
Published: January 2018

Abstract
An analysis and a synthesis of published and original experimental evidence have been performed with a view to providing a global qualitative and quantitative description of the proliferation of monocyte precursors in murine bone marrow. Two versions of a mathematical model are proposed. The first consists of two dividing generations of granulocyte-macrophage colony-forming cells (GM-CFC) and two dividing generations of macrophage colony-forming cells (M-CFC), differentiating into promonocytes (PM) and then into monocytes (MC). The second version consists of two generations of GM-CFC and three generations of M-CFC, followed by PM and MC. Both are compatible with experimental data, and further evidence is needed to elaborate a unique representation. The kinetic constants have been taken from published material whenever possible and estimated from available data and model kinetics in the case of unknown quantities. The models are applied to a pulse labeling assay, and calculated labeled subpopulations are compared with experimental values. Agreement is satisfactory for both versions in the case of MC, while a calculated PM labeling index falls more rapidly than the experimental values. However, inconsistency also exists between PM and MC experimental data.
Mitochondrial Biogenesis During the Activation of Lymphocytes by Mitogens: The Immunosuppressive Action of Tetracyclines
Authors: Van den Bogert C , Melis T E , Kroon A M 
Published: January 2018

Abstract
The role of mitochondrial biogenesis and function during mitogenic stimulation of rat thymocytes was investigated. The results show that mitochondrial biogenesis is required to provide the ATP for the energy-requiring processes occurring during blastogenesis. Impairment of mitochondrial biogenesis by inhibition of mitochondrial protein synthesis inhibits blast transformation. Since the tetracyclines impair mitochondrial protein synthesis, the results offer an explanation for the well-known immunosuppressive effects of these antibiotics.
Activation of Human T Lymphocytes by Crosslinking of Anti-CD3 Monoclonal Antibodies
Authors: Dixon James F P , Law Judy L , Favero Jean J 
Published: January 2018

Abstract
The proliferation of human T lymphocytes induced by anti-CD3 monoclonal antibodies (mAb) is used as a model for antigen-induced activation via the T cell receptor-CD3 complex. Since both systems are accessory cell (AC)-dependent, an understanding of the role of AC in anti-CD3-induced proliferation may provide an understanding of physiological activation via the T cell receptor. Previous work has implicated receptor crosslinking as an important AC function. To determine its necessity in anti-CD3-induced lymphocyte proliferation, we prepared highly purified T lymphocytes and found that these cells did not respond to the anti-CD3 mAb UCHT1, either alone or with interleukin 1 (IL1), interleukin 2 (IL2), or tetradecanoyl phorbol acetate (TPA). However, the response, as measured by appearance of IL2 receptors and proliferation, was restored by crosslinking with immobilized goat anti-mouse antibodies (GAM) and did not require the addition of IL1, IL2, or TPA. Thus, crosslinking of CD3 receptors was a sufficient signal for proliferation of these cells. Cyclosporine A (CsA) inhibited the activation induced by immobilized UCHT1. Since macrophages are the principal targets of CsA-mediated suppression of mitogen-induced proliferation, but macrophages do not participate in the response to immobilized anti-CD3, this may indicate that CsA was inhibiting crosslinking or a signal generated by it.
Rat Bone Marrow and Monocyte Cultures: Influence of Culture Time and Lymphokines on the Expression of Macrophage Differentiation Antigens
Authors: Damoiseaux J G M C , Döpp E A , Beelen R H J , Dijkstra C D 
Published: January 2018

Abstract
A set of seven monoclonal antibodies (moabs) has been shown to discriminate in situ between distinct subpopulations of macrophages in the rat. It is still controversial if this heterogeneity is caused by the existence of different lineages or by differentiation of a common precursor. In both cases, the differentiation process might be regulated by microenvironmental factors. The present study examines the expression of the macrophage markers recognized by the seven ED-moabs in bone marrow and monocyte cultures. Furthermore, the impact of culture time and stimulating factors on the antigen expression in these cultures was tested. The expression of the ED3 antigen is highly inducible in bone marrow cultures. Factors that might be responsible for the increased ED3 expression are investigated. This strong ED3 expression by bone marrow-derived macrophages is nearly absent by monocyte-derived macrophages. This implies that the ability to express ED3 is blocked before the macrophage precursor cells enter the circulation to become monocytes. The ED2 expression cannot be induced under the tested circumstances during culture. The expression of ED7 and ED8 is also highly inducible because bone marrow macrophages in vivo do not express these antigens. In culture, these macrophages stain positive for these markers already after the first day of culturing. The other three antigens are expressed on all macrophages under all tested circumstances.
Leukotriene B4 Modulates Phospholipid Methylation and Chemotaxis in Human Polymorphonuclear Leukocytes
Authors: Bomalaski John S , Dundee David , Brophy Lynne , Clark Mike A 
Published: January 2018

Abstract
Formation of phosphatidylcholine from phosphatidylethanolamine via the S-adenosylmethionine (AdoMet) pathway has been shown to be required for signal transduction of receptor–ligand interactions in a variety of cells. These interactions result in the remodeling of phospholipid pools and phospholipase activation. To extend these observations and to explore the role of the phosphatidylcholine synthesis pathway in transduction of the leukotriene B4 (LTB4) receptor–ligand response, we examined phospholipid methylation in human polymorphonuclear leukocytes (PMN) following stimulation by LTB4, a potent chemotactic agent that is a metabolite of arachidonic acid. At early time points (~3–10 min), formation of methylated phospholipids was enhanced following LTB4 stimulation. The LTB4 analogs 6-trans LTB4 as well as LTB4 epimers induced less methylation compared with LTB4, and the potencies of these analogs in inducing methylation correlated with their diminished ability to induce chemotaxis. Furthermore, the ability of these agonists to induce methylation also correlated with the binding affinity of these agents to the LTB4 receptors on these cells. Synthesis of phosphatidylcholine by the choline transferase pathway was not affected by LTB4. Inhibition of the AdoMet reaction with 3- deazaadenosine, L-homocysteine homolactone, or erythro-9-[2-hydroxy-3-nonyl] adenine (EHNA) abrogated LTB4-induced phospholipid methylation and the chemotactic response. The potencies of these inhibitors in blocking phospholipid methylation also correlated with their ability to abrogate the LTB4-induced chemotactic response. These data suggest that phospholipid methylation and phospholipase activation play an important role in transduction of the LTB4 receptor–ligand interaction in PMN, which results in chemotaxis.
Interactions of Virulent and Avirulent Legionella pneumophila With Human Monocytes
Authors: Summersgill James T , Raff Martin J , Miller Richard D 
Published: January 2018

Abstract
Four pairs of virulent/avirulent strains of Legionella pneumophila were examined for their adherence/uptake and activation of human monocytes. Oxidative metabolic responses of monocytes were quantitated by measuring intracellular hydrogen peroxide generation using flow cytometry and by assessment of superoxide dismutase-inhibitable superoxide anion generation. All L pneumophila strains induced less of a response than did Escherichia coll. Within each pair of isolates, virulent strains of L. pneumophila stimulated the oxidative response of monocytes less than avirulent variants. To determine effects of complement fixation by each strain on their adherence to monocytes, a phagocytic index (PI) was determined under various conditions. In autologous donor serum (AS), all L. pneumophila strains had a PI in the range of 2.1–3.1 bacteria per monocyte, with E. coll having a PI of 9.1. No significant differences were observed between virulent L pneumophila strains and their avirulent variants. In the presence of heat-inactivated AS, all PI fell to 0.13–0.20 for the L pneumophila strains, and to 2.16 for E. coll. Using heat-inactivated AS reconstituted with exogenous human complement as a source of opsonization, levels of PI were indistinguishable from their respective levels in AS. This suggests that complement fixation plays an important role in the adherence of virulent and avirulent L pneumophila to human monocytes.
An Endotoxin-lnduced Factor Distinct From lnterleukin-1 and Tumour Necrosis Factor α Produced by the THP-1 Human Macrophage Line Stimulates Polymorphonuclear Leukocyte Infiltration In Vivo
Authors: Megyeri Pal , Issekutz Thomas B , Issekutz Andrew C 
Published: January 2018

Abstract
Endotoxin and gram-negative bacteria induce vigorous inflammatory reactions. Our previous work showed that rabbit macrophages (M⊘) incubated with endotoxin produce a 45,000 darton protein that recruited polymorphonuclear leukocytes (PMNL) into the skin of rabbits. This factor was separated from lnterleukin-1 (IL-1) but could not be unequivocally distinguished from rabbit tumour necrosis factor (TNFα). Here we have examined the human Mo cell line, THP-1, for the production of an analogous protein. After exposure to phorbol diester the THP-1 cells assumed the characteristic M⊘ phenotype and function. During 6 hours of culture with LPS these Mo released a factor(s) that caused PMNL recruitment into the skin of rabbits when injected intradermally, measured using 51Cr-labelled blood leukocytes. This activity, referred to as PMNL recruiting activity (PRA), was heat labile, and its production was blocked by cycloheximide, suggesting that this is most likely a de novo synthesized protein. Sephadex-G 100 and Superose-12 FPLC chromatography indicated a molecular weight in the 45,000–65,000 dalton range. The active fractions were free of IL-1 activity (&lt; 0.2 U/ml), and Superose-12 chromatography separated the peak of PRA, which eluted around 45,000 daltons, from TNFα eluting at 20,000 daltons. The peak PRA was not neutralized by antiserum to IL-1α, IL-1β TNFα, IL-6, and granulocyte-macrophage colony-stimulating factor (GMCSF), indicating that it was distinct immunologically from these cytokines. The major PRA did not induce migration of rabbit or human PMNLs in vitro in a Boyden chamber chemotaxis assay, although peaks of chemotactic activity and weak PMNL recruitment in vivo were detected in fractions eluting around 15,000 daltons and 800 daltons. The generation of PRA by a human Me cell line is analogous to that reported previously with rabbit Me. Here we extend these observations to a human Me system and confirm that this molecule is distinct from several other Me cytokines and Me chemotactic factors with inflammatory properties.
Interferons Exhibit Temporally Distinct Regulation of Two Bovine Macrophage Fc Receptors
Authors: Pontzer Carol H , Russell Stephen W 
Published: January 2018

Abstract
Interferon (IFN)-induced modulation of two distinct types of Fc receptors (FcR) on bovine bone marrow culture-derived macrophages was quantified by flow cytometry. We have established the presence of separate FcR for monomeric and aggregated IgG on these cells, equivalent to the FcRI and FcRII of mice, respectively. These two kinds of FcR differed in protease sensitivity, hierarchy of preferential binding of immunoglobulin subclass, and cross-inhibition. Treatment of macrophages with either recombinant bovine IFN-gamma (rBolFNγ) or rBolFNα1 produced a dose-dependent increase in the expression of both types of FcR; however, expression of the FcR for aggregated IgG was increased a full 24 h prior to that for monomeric antibody. Further, expression of the FcRII-equivalent declined substantially by 48 h of IFN exposure, while the presence of the FcRI-equivalent receptor was still enhanced. Finally, low doses (1 unit/ml) of either rBolFNγ or rBolFNα1 failed to alter FcR expression, yet mixtures of IFNs at this concentration were able to potentiate FcR expression. This is the first time that a differential time course of induction of FcR types by IFNs and the effects of mixtures of IFNs on FcR expression has been described in any species.
Simultaneous Flow Cytometric Measurements of Cytoplasmic Ca++ and Membrane Potential Changes Upon FMLP Exposure as HL-60 Cells Mature Into Granulocytes: Using [Ca++]in as an Indicator of Granulocyte Maturity
Authors: Bernardo John , Newburger Peter E , Brennan Lisa , Brink Holly F , Bresnick Sandra A , Weil Gary , Simons Elizabeth R 
Published: January 2018

Abstract
Treatment of human leukemic HL-60 cells with N,N-dimethylformamide (DMF) induces them to mature until they reach granulocytoid morphology 3–6 d later. We have reported a maturation-dependent ability of these cells to respond to phorbol myristate acetate (PMA), as evaluated by membrane depolarization and by oxidative burst product formation (Newburger et al.: J. Biol. Chem. 259, 3771, 1984). More recently we have attempted to develop techniques for simultaneous evaluation of these parameters during HL-60 cell maturation. Here, we compare the cytoplasmic [Ca+ +] and membrane potential changes elicited by the chemotactic peptide fMLP via simultaneous measurement of individual cells in a fluorescence-activated cell sorter (FACS), as done previously for mature granulocytes (Lazzari et al.: J. Biol. Chem. 261,9710, 1986). The stimulus-induced [Ca++]in changes are detected with the fluorescent probe lndo-1 and reproducibly increase in magnitude for a subpopulation of cells as the cells mature into granulocytes. Ca+ + responsiveness to formyl peptide is restricted to a subpopulation of HL-60 granulocytes which expresses receptors for chemotactic peptide and consistently increases in magnitude (in response to the same concentration of agonist) with maturation. In contrast, there is less consistency in the direction or magnitude of membrane potential changes elicited under the same circumstances from the same maturing HL-60 cells.