bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence That Specific High-Mannose Oligosaccharides Can Directly Inhibit Antigen-Driven T-Cell Responses
Authors: Muchmore Andrew V , Sathyamoorthy Neeraja , Decker Jean , Sherblom Anne P 
Published: January 2018

Abstract
Uromodulin is an 85 Kd immunosuppressive glycoprotein originally isolated from human pregnancy urine. It is unique in that most of its biologic activity can be attributed to attached oligosaccharides. Purified immunomodulatory oligosaccharides from uromodulin have been structurally characterized using 1H-NMR spectroscopy and shown to be Man6–7GlcNAc2(M6,117). Based on these observations, we isolated high-mannose N-type oligosaccharides and glycopeptides from ovalbumin, soybean agglutinin, and yeast mannan and show that these high-mannose compounds directly inhibit in vitro antigen-driven T-cell proliferation from millimolar to nanomolar concentrations. The most active compound was a core mannose oligosaccharide derived from yeast mannan, M9(y), which acts to block early events required for normal antigen processing/presentation. These data emphasize the potential functional role of carbohydrate structure in regulating the human immune response.
Distribution of Neutral Endopeptidase Activity in Human Blood Leukocytes
Authors: Iwamoto Itsuo , Kimura Akira , Ochiai Kenichi , Tomioka Hisao , Yoshida Sho 
Published: January 2018

Abstract
We investigated the distribution of neutral endopeptidase (NEP; EC 3.4.24.11) activity, a possible regulatory enzyme for neuropeptide-induced leukocyte activations, in each cell type of human blood leukocytes. The NEP activity assessed by an NEP inhibitor phosphoramidon-sensitive Met5-enkephalin degrading activity was present in neutrophils and the common acute lymphoblastic leukemia antigen (CALLA)-positive leukemic cells (59 pmol/min/106 cells and 62 pmol/min/105 cells, respectively); however, the NEP activity was virtually absent in lymphocytes, monocytes, eosinophils, basophils, CALLA-negative leukemic cells, or a promyelocytic cell line HL-60. The enzymatic activity was characterized as NEP on the basis of the values of kinetic parameters (Km = 61 μM, Kcat = 1,692 min-1, and Kcat/Km = 28 min-1/μM-1) and the values of IC50 of two NEP inhibitors phosphoramidon and thiorphan (7.4 nM and 8.4 nM, respectively). The distribution of NEP detected immunocytochemically using anti-NEP monoclonal antibodies was also found to be parallel with the distribution of NEP activity among peripheral blood leukocytes.
Neutrophil-Specific Antigen NB1 Is Anchored Via a Glycosyl-Phosphatidylinositol Linkage
Authors: Skubitz Keith M , Stroncek David F , Sun Bo 
Published: January 2018

Abstract
Neutrophil-Specific alloantibodies and the antigens they recognize are important in clinical medicine but little is known about the structure of these antigens. Alloimmunization to the antigen NB1 is a clinically important cause of neonatal neutropenia and leukocyte-mediated transfusion reactions. A novel mechanism of protein attachment to cell membranes involving the covalent linkage of the protein through an oligosaccharide to phosphatidylinositol has recently been defined. Many proteins which are anchored to the cell membrane by this mechanism can be released by treatment with phosphatidylinositol-specific phospholipase C (PI-PLC). The 58–64-kDa human neutrophil surface protein which contains the NB1 antigen was labeled with 125I by using lactoperoxidase and examined for PI-PLC sensitivity. The 58–64-kDa protein was specifically released from the cell by treatment with PI-PLC, and the mobility of the protein under non-denaturing conditions using non-ionic detergent was increased by treatment with PI-PLC. Surface expression of the NB1 antigen was slightly up-regulated by treatment with the chemotactic peptide f-met-leu-phe. Removal of N-linked carbohydrates with endoglycosidase-F decreased the apparent molecular weight of the protein to ~45-kDa. The data suggest that most of the 58–64-kDa protein bearing the neutrophil-specific antigen NB1 is anchored to the membrane through a glycosyl-phosphatidylinositol linkage.
Cyclic AMP Inhibits Secretion From Electroporated Human Neutrophils
Authors: Smolen James E , Stoehr Sally J , Kuczynski Barbara 
Published: January 2018

Abstract
It has long been known that Intracellular cAMP inhibits and cGMP enhances intact neutrophil function. However, these effects are modest and require relatively high concentrations of the cyclic nucleotides. We decided to re-examine the effects of cyclic nucleotides on Ca2+-induced secretion by electroporated cells. This system allowed us to bypass normal cell surface receptor-ligand interactions as well as to directly expose the intracellular space to native cyclic nucleotides. We found that concentrations of cAMP as low as 3 μM inhibited Ca2+-induced secretion; 30–300 μM cAMP was maximally inhibitory. cAMP was actually slightly more potent than dibutyryl cAMP, a membrane-permeant derivative. In contrast, cGMP was only slightly stimulatory at 3 μM and modestly inhibitory at 300 μM; dibutyryl cGMP was ineffective. A more detailed investigation of the effects of cAMP showed that inhibition was only obtained in the presence of Mg2+. Half-maximal inhibition by cAMP occurred at 10–30 μM. Inhibition by cAMP was achieved by shifting the Ca2+ dose-response curve for secretion to the right; this was observed for the release of both specific granules (vitamin B12 binding protein) and azurophil granules (B-glucuronidase). We previously showed that ATP could enhance Ca2+-induced secretion in the presence of Mg2+, apparently by interacting with a cell surface purine receptor. However, increasing concentrations of ATP could not overcome inhibition by cAMP; this suggested that cAMP acted at some site other than the purine receptor. Inhibition by cAMP was also less apparent in the presence of the protein kinase C agonist phorbol myristate acetate (PMA), suggesting that the cyclic nucleotide did not produce systemic desensitization of the neutrophils. In summary, these results demonstrate that low, physiologically relevant concentrations of cAMP can modulate neutrophil responsiveness.
Stimulation of Human Peripheral Blood Polymorphonuclear Cell Iodination by Lignin-Related Substances
Authors: Sakagami Hiroshi , Kawazoe Yutaka , Oh-hara Toshinari , Kitajima Ken , Inoue Yasuo , Tanuma Sei-ichi , Ichikawa Shinya , Konno Kunio 
Published: January 2018

Abstract
Lignin is a heterogeneous natural product composed of phenylpropane units and is usually associated with hemicellulose in its native state. Until now little attention has been paid to the potential therapeutic utility of lignified products. Natural lignified products are demonstrated in the present study to stimulate iodination significantly (incorporation of radioactive iodine into an acid-insoluble fraction) of human peripheral blood polymorphonuclear cells (PMN). This stimulation was significantly inhibited in the presence of myeloperoxidase inhibitors. These materials were almost completely deprived of their stimulation capacity by treatment with NaCIO2, but this capacity was not affected by severe treatment with H2SO4 or trifluoroacetlc acid. Similar stimulating activity by chemically defined tannin-related polyphenolic compounds was observed. Degradation products or component units of lignin, and natural antitumor polysaccharides and their chemically modified derivatives (introduced with negatively or positively charged groups) and polysialoglycoproteins had little or no activity. The results indicate the importance of a polymerized phenolic structure for the stimulation of PMN iodination. Possible physiological relevance of the stimulation of iodination by lignified substances is discussed.
Tumor Necrosis Factor-α Is Chemokinetic for Lymphokine-Activated Killer Cells: Regulation by Cyclic Adenosine Monophosphate
Authors: Maghazachi Azzam A 
Published: January 2018

Abstract
The ability of tumor necrosis factor-α (TNF-α) to attract lymphokine-activated killer (LAK) cells in vitro was examined. Utilizing modified Boyden chambers (BC), it was observed that TNF-α is not chemoattractant for LAK cells. On the other hand, TNF-α attracted both fresh and concanavalin A-activated T cells. However, when TNF-α was incubated in the upper compartments of BC and in the presence of LAK cells, it enhanced the random movement of these cells across the polycarbonate membranes. The effect of TNF-α was inhibited by incorporating anti-TNF-α antibody, or a high concentration (10 ng) of TFG-β1. The activity of TGF-β1 was reversed by anti-TGF-β1 antibody. Cholera toxin (CT), which is known to activate the endogenous level of cyclic adenosine monophosphate (cAMP) also inhibited TNF-α-induced LAK cell chemokinesis. The effect of CT was mimicked by the cAMP analog dibutyryl cAMP or by the phosphodiesterase inhibitors isobutyl methylxanthine or aminophylline. Measurement of the intracellular level of cAMP showed that cells incubated for 1,2, or 4 hr with TNF-α have a lower level of cAMP, whereas those incubated with a high concentration of TGF-β1 produced significantly higher levels of this messenger. cAMP level was also increased in cells incubated with TGF-β1 plus TNF-α. This level was reduced to the background when anti-TGF-β1 antibody was added to the cultures. These results suggest that cAMP negatively regulates LAK cell chemokinesis.
Translocation of CD45RA in Neutrophils
Authors: Caldwell Charles W , Patterson William P , Yesus Yohannes W 
Published: January 2018

Abstract
The CD45 family of high-Mr glycoprotein antigens is expressed in some molecular form on all lymphohematopoietic cells. Different cell types express various isoforms in a precisely programmed fashion. In addition to cell surface CD45 antigens, we recently demonstrated a cytoplasmic granule-associated pool of CD45RA, the highest Mr isoform, in mature neutrophils that is generally absent from the cell surface under nonstimulatory conditions. Under such conditions, the major cell surface form is CD45RO, the low-Mr isoform. In the present study, we demonstrate the ability of calcium ionophore A23187 to induce translocation of cytoplasmic CD45RA to the cell surface as well as to increase the cell surface expression of CD45RO and CD45. This process was calcium dependent and rapid, occurring within 5 min. A series of experiments using chemical antagonists of protein kinases suggest that this up-regulation may be mediated via the calmodulin system rather than via protein kinase C. Although the exact function(s) of the various isoforms of CD45 is not known, this translocation suggests a role for CD45RA in neutrophil activation.
Activation of the Neutrophil NADPH-Oxidase by Free Fatty Acids Requires the Ionized Carboxyl Group and Partitioning Into Membrane Lipid
Authors: Steinbeck Marla J , Robinson John M , Karnovsky Morris J 
Published: January 2018

Abstract
To investigate NADPH-oxidase activation, we studied the effects of free fatty acid (FFA), their uncharged derivatives, and calcium on membrane lipid structure and superoxide anion (O–2) release from intact neutrophils and in cell-free O–2-generating systems. This study determined that in calcium-free phosphate-buffered saline (PBS), cis-unsaturated FFA (cis FFA), trans-unsaturated FFA (trans FFA), and to a limited extent saturated FFA decreased the polarization of the membrane lipid structure probe 1,6-diphenyl-1,3,5-hexatriene (DPH), and these decreases correlated with partitioning of the FFA into the plasmalemma and the release of O–2 from intact neutrophils and in cell-free preparations. Although a decrease in DPH polarization was always observed under conditions that resulted in the release of O–2, there was not a direct correlation between the amount of decrease in DPH polarization and the release of O–2. Trans FFA did not induce a dose-dependent decrease or as dramatic a decrease in DPH polarization compared with cis FFA, yet the trans FFA stimulated a greater release of O–2 at 2.5, 5, and 10 µM concentrations. In addition, responses of the neutrophil to trans FFA, but not cis FFA, were differentially affected by the presence of calcium. When 0.1 mM calcium was added to the PBS decreases in DPH polarization in response to trans FFA were reduced by &gt;60%, whereas O–2 was reduced by only 25–36%. The addition of 0.1 mM calcium 3 min after the trans FFA had partitioned into the membrane also reversed by 50–65% decreases in DPH polarization but did not affect the release of O–2. In the presence of 0.9 mM calcium, only the cis FFA decreased DPH polarization or stimulated the release of O–2. Calcium is known to interact more readily with the ionized carboxyl group of trans FFA, neutralizing the anionic charge through an electrostatic interaction. In support of the requirement for the ionized carboxyl group, structurally similar uncharged cis, trans, and saturated fatty alcohols; methyl esters; and aldehydes decreased DPH polarization in the absence and presence of 0.9 mM calcium; however, none of these compounds stimulated the release of O–2. These results indicate that, in addition to the partitioning of FFA into the plasmalemma, which results in calcium-modulatable decreases in DPH polarization, activation or assembly of the NADPH-oxidase requires the ionized carboxyl group.
Intracellular Localization of a Lipopeptide Macrophage Activator: Immunocytochemical Investigations and EELS Analysis on Ultrathin Cryosections of Bone Marrow-Derived Macrophages
Authors: Uhl B , Wolf B , Schwinde A , Metzger J , Jung G , Bessler W G , Hauschildt S 
Published: January 2018

Abstract
Synthetic lipopeptides, structurally derived from the N-terminal part of bacterial lipoprotein, constitute macrophage and B-lymphocyte activators. The molecular mechanism of macrophage activation by lipopeptides still remains unclear. The purpose of our study was to determine the route and kinetics of lipopeptide distribution in bone marrow-derived macrophages. The intracellular localization of the C-terminally biotinylated lipodipeptide Pam3Cys-Ser was investigated on ultrathin cryosections using the biotinstreptavidin-gold system. Our findings indicate that the lipopeptide penetrates the plasma membrane and can already be found within the cytoplasm, the nuclear membrane, and within the nucleus after 2 min of stimulation. The pattern of lipopeptide distribution obtained 2 min after stimulation resembles that obtained after longer incubation times (8 and 20 min). Correlating distribution patterns were observed when using the method of electron energy loss spectroscopy (EELS). These findings are a clear indication for the rapid uptake of lipopeptides into eukaryotic cells, and are of importance for further studies of the immunostimulating properties of the bacterial lipopeptides and vaccines derived therefrom.
Mononuclear Cell Adherence Induces Neutrophil Chemotactic Factor/Interleukin-8 Gene Expression
Authors: Kasahara Keita , Strieter Robert M , Chensue Stephen W , Standiford Theodore J , Kunkel Steven L 
Published: January 2018

Abstract
The accumulation of polymorphonuclear cells (PMN) in tissue is an essential element of the inflammatory response that is important in host defense. Adherence to endothelium constitutes the first step in PMN migration from the vascular compartment to the interstitium. We demonstrate that human peripheral blood mononuclear cells (PBMC) adherent to plastic can result in expression of interleukin-8 (IL-8), a potent PMN chemoattractant and activating cytokine. Northern blot analyses showed PBMC adherent to plastic expressed IL-8 steady-state mRNA levels by 30 min, peaked at 8 h, and then decreased over the next 16 h. In contrast, nonadherent PBMC (cultured in teflon chambers) expressed less than 25% of the maximal IL-8 steady-state mRNA levels as compared with adherent PBMC. Adherent PBMC-associated IL-8 determined by immunohistochemistry, supernatant chemotactic bioactivity, and extracellular antigenic IL-8 paralleled IL-8 mRNA expression. Antigenic and bioactive IL-8 were significantly apparent by 4–8 h, respectively, and increased significantly to maximal levels by 24 h. Furthermore, adherent PBMC IL-8 gene expression was suppressed by either concomitant treatment with actinomycin-D or cycloheximide, yet specific neutralizing antibodies directed against either IL-1β or tumor necrosis factor (TNF)-α failed to alter adherence-induced steady-state IL-8 mRNA levels. These data support the hypothesis that PBMC adherence is an important signal for the production of IL-8, and may be essential to the development of the inflammatory response through the elicrtation of PMN.
Porcine Alveolar and Pulmonary Intravascular Macrophages: Comparison of Immune Functions
Authors: Chitko-McKown C G , Chapes S K , Brown R E , Phillips R M , McKown R D , Blecha F 
Published: January 2018

Abstract
Although a substantial amount of information is available on pulmonary alveolar macrophages (PAMs), little is known about pulmonary intravascular macrophages (PIMs), a separate population of lung macrophages found apposed to the endothelium of pulmonary capillaries. We compared these two populations of lung immunocytes to determine their relative immunological activity. Our results suggest that PAMs are more phagocytic than PIMs; however, PIMs may be more efficient at lysing ingested bacteria than PAMs. Although similar in antibody-dependent cellular cytotoxicity, PIMs are more spontaneously cytolytic than PAMs. Depending upon the effector:target cell ratio studied, the tumoricidal activity of PIMs was less than or equal to that of PAMs. Both cell populations produced the cytokines interleukin-1 and tumor necrosis factor-α at similar concentrations. These data suggest that PIMs are immunologically active, although the degree of activity may differ between PIMs and PAMs.
Adhesion of Human Neutrophils to and Activation by Type-I Collagen Involving a β2 Integrin
Authors: Monboisse Jean-Claude , Garnotel Roselyne , Randoux Alain , Dufer Jean , Borel Jacques-Paul 
Published: January 2018

Abstract
We previously demonstrated that the α1(l) polypeptide chain of collagen can bind and activate polymorphonuclear neutrophils (PMN). In the present experiments, performed in culture grade 96-well plastic plates coated with collagen, fibronectin, or other proteins, adhesion was assessed by staining the adhering cells after 30 min with crystal violet and measuring absorbance at 560 nm, and activation of PMNs was assessed by measuring the amount of O2- formed. Adhesion occurred at 17 and 37°C but activation at 37°C only. Monoclonal antibody anti-CD 18 inhibited adhesion, showing that the receptor of collagen I on PMNs is a β2 integrin. On the other hand, adhesion of PMNs to fibronectin was inhibited by monoclonal antibodies to CD18 and to CD11b.
Lipoxin-induced migration of fish leukocytes
Authors: Sharp Gregory J E , Pettitt Trevor R , Rowley Andrew F , Secombes Christopher J 
Published: January 2018

Abstract
The migration-inducing abilities of both synthetic lipoxin A4 (LXA4) and leukotriene B4 (LTB4) for rainbow trout neutrophils were examined with an in vitro assay. LXA4 caused enhanced migration of these cells with a three- to fourfold greater response than that observed toward LTB4 at most concentrations tested. Checkerboard assays showed that synthetic LXA4 was chemokinetic for trout leukocytes, while LTB4 was chemotactic. The chemokinetic ability of LX synthesized by rainbow trout macrophages maintained in short-term culture was also determined. These cells produced both 4-and 5-series LX, namely LXA4, LXA5, 11-trans-LXA4, 11-trans-LXA5, 7-cis-11-trans-LXA4 and 6(S)-LXA4. Although greater migration was found to LXA4 than to most of the other 4-series positional isomers, at least at some concentrations, this did not exhibit the degree of stereospecificity previously reported in some studies for mammalian leukocytes. Little difference was found between the chemokinetic responses of rainbow trout leukocytes to 4- and 5-series LX. These findings suggest that LXs are important migration-inducing molecules in trout and have a relatively long evolutionary history.
Anomalous features of human neutrophil activation by influenza A virus are shared by related viruses and sialic acid–binding lectins
Authors: Hartshorn Kevan L , Daigneault David E , White Mitchell R , Tauber Alfred I 
Published: January 2018

Abstract
Influenza A virus (IAV) causes both activation and deactivation of the human neutrophil, which may, respectively, contribute to host defense against the virus and enhanced susceptibility to bacterial superinfection. We have shown that certain features of neutrophil activation by IAV are distinctive compared with activation by chemoattractants in terms of both the stoichiometry of the respiratory burst response and the signal transduction events that precede it. We here demonstrate that related myxoviruses as well as sialic acid–binding lectins elicit a respiratory burst response similar to that induced by IAV, in which hydrogen peroxide is formed with minimal accompanying superoxide generation. Brief preincubation of neutrophils with these agents fully inhibits subsequent activation by IAV, implying that they are binding to the same surface membrane components as IAV. Preincubation with Limax flavus agglutinin (LFA) does, in fact, substantially reduce binding of radiolabeled IAV to the neutrophil. This lectin, like IAV, both activates and deactivates the neutrophil. As in the case of IAV, LFA-induced activation (1) is mediated via stimulation of phospholipase C, (2) is pertussis toxin insensitive, and (3) entails a lesser contribution of calcium influx than is the case for chemoattractants.
Urokinase expression in mononuclear phagocytes: cytokine-specific modulation by interferon-γ and tumor necrosis factor-α
Authors: Gyetko Margaret R , Shollenberger Susan B , Sitrin Robert G 
Published: January 2018

Abstract
This study delineates the regulatory effects of inflammatory cytokines on mononuclear phagocyte plasminogen activator (PA) activity. The mechanisms by which mononuclear phagocytes modulate PA activity are described. Mononuclear phagocytes regulate net PA activity by the balanced expression of urokinase-type PA (uPA), in either secreted or membrane-associated forms, and a specific plasminogen activator inhibitor, PAI-2. Therefore, understanding how immunomodulators regulate macrophage PA activity requires that the comparative effects of uPA and PAI-2 be elucidated. We determined how recombinant interferon-γ (IFN) and tumor necrosis factor-α (TNF) regulate plasminogen activation in monoblast-like U937 cells and normal human monocytes. In U937 cells, both IFN and TNF induced concurrent increases in secreted PA and PA inhibitor activities. These effects were accompanied by increased immunoreactive uPA and PAI-2 in conditioned media (enzyme-linked immunosorbent assay) and steady-state levels of cellular uPA and PAI-2 mRNA (Northern analysis). To determine the relative abilities of IFN and TNF to either promote or inhibit plasmin generation, we directly compared the effects IFN and TNF, using optimal stimulating concentrations. IFN induced PA activity to 180% of the level achieved by TNF. In contrast, IFN elicited only 78% of the PA inhibitor produced by TNF stimulation. These differences in secreted activity can be explained by the shift in balance between uPA and PAI-2 proteins. Immunoreactive uPA was induced equally by IFN and TNF, but TNF generated higher levels of PAI-2. The same overall pattern of results was seen in normal human monocytes. IFN and TNF differ greatly in the ability to augment receptor-bound PA activity in U937 cells, as IFN induced a twofold increase but TNF had no effect. We conclude that IFN and TNF modulate mononuclear phagocyte proteolytic activity through coordinate regulation of secreted and receptor-bound uPA, balanced against concurrent expression of PAI-2. These effects are cytokine specific, as IFN is superior to TNF in stimulating expression of both secreted and receptor-associated PA activities. These properties suggest mechanisms by which mononuclear phagocytes control proteolysis in cytokinerich inflammatory foci.