Thèses : « Immunology, Neutrophil »

1

Eckert, Rachael. « Molecular Mechanisms of Neutrophil Migration ». NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-10312007-134315/.

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This work is an investigative look behind the mechanisms of neutrophil migration. Each of three chapters involves exploration into a different signaling pathway important for migration downstream of chemoattractant stimulation through inhibition of a kinase or disruption of the function of an effector and examination of the effects on migration, adhesion, and actin reorganization in primary human or equine neutrophils. Chapter II examines the requirement for the signaling molecule p38 Mitogen Activated Kinase (MAPK) in equine neutrophil chemotaxis through use of the p38 specific inhibitor SB203580. SB203580 reduced LTB4- and PAF-induced migration and disrupted the ability of cells to polarize, but did not affect b2 integrin-dependent adhesion or surface b2 integrin expression. Chapter III is a comprehensive inquiry into the regulation of the phosphorylation of serine 157 of the cytoskeletal protein Vasodilator-stimulated Phosphoprotein (VASP). The rapid and transient phosphorylation of VASP serine 157 corresponded with F-actin levels in chemoattractant-stimulated human neutrophils. fMLF-induced serine 157 phosphorylation was abolished by pretreatment with the PKA inhibitor H89 and the adenylyl cyclase inhibitor SQ22536. In contrast, fMLF-induced serine 157 phosphorylation was unaffected by PKC inhibitors, PKG inhibitors, and the CamKII inhibitor KN-62. Inhibition of adhesion did not alter fMLF-induced VASP phosphorylation or dephosphorylation. This study demonstrated that chemoattractant stimulation of human neutrophils induces a rapid and transient PKA-dependent and adhesion-independent VASP serine 157 phosphorylation. Chapter IV probed into the function of the actin binding protein and PKC substrate Myristoylated Alanine-Rich C-kinase Substrate (MARCKS) through utilization of a cell permeant peptide derived from the MARCKS myristoylated aminoterminus (MANS peptide). Treatment of isolated human neutrophils with 50 μM MANS, but not a scrambled control peptide, significantly inhibited their migration and adhesion in response to fMLF, IL8, or LTB4. MANS significantly reduced F-actin content in neutrophils 30s after fMLF-induced polymerization, but did not alter the ability of cells to polarize, spread, or upregulate surface b2 integrin expression. These data provided evidence that MARCKS, via its myristoylated aminoterminus, is a key regulator of neutrophil migration and adhesion.

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2

Rochon, Yvan P. (Yvan Pierre). « Dynamics of neutrophil aggregation ». Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=70210.

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Neutrophil aggregation has been widely evaluated from changes in light transmission. Using direct particle counting, we demonstrated that light transmission does not accurately reflect aggregation, and showed that in contrast to previous reports, newborn neutrophils do not aggregate irreversibly. We developed a flow cytometric technique to measure the kinetics of neutrophil aggregation, including latent times for onset of aggregation, initial forward and reversal rates, and maximal extents of aggregation. The kinetics of neutrophil aggregation were related to changes in initial cell concentration, stir speed (shear), and activator type and concentration. Physiologic activators stimulated reversible aggregation, accompanied by an exponential decay in aggregatory potential with increasing time. The fraction of occupied activator receptors was found to correspond to the fraction of maximal rates or extent of aggregation. Monoclonal antibodies were used to show that neutrophil aggregation is mediated by the Mac-1 integrin (CD11b/CD18). Direct measurements of aggregation have enhanced our understanding of the (patho)physiologic process of neutrophil aggregation.

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Macdonald, Elizabeth A. « Bovine neutrophil functionality in mastitis resistance ». Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68211.

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Diapedesis, phagocytosis and microbicidal activity are important parameters of neutrophil functionality and thus outcome of mastitis. An in vitro model of an "alveolar pavement" using the MAC-T3 bovine mammary epithelial cell line was developed to assess neutrophil diapedesis. Features of this biologically-meaningful barrier include: characteristic transepithelial resistance, tight junction complexes and polarity. Continuous transepithelial resistance measurements showed no significant changes throughout the assay period. Neither a Staphylococcus aureus challenge ($1 times10 sp7$ and $2 times10 sp9$ cfu/ml), or the presence of neutrophils, both resting and challenged had any deleterious effects on monolayer integrity over a short term (1-2 h) exposure. Neutrophils, both resting and challenged gave no indication of causing damage to the epithelium over the short term. Neutrophils isolated from proven sires and evaluated for phagocytic activity were found to differ significantly (p $<$ 0.05) in activity, rate and capacity to uptake particles. Correlations between phagocytic parameters and production traits were negative and small in magnitude. Microbicidal activity of neutrophils isolated from proven sires showed a highly significant variation between animals due to test day (p $<$ 0.001), however variation due to source of cells (i.e. animal) was not significant. in vitro analysis of diapedesis and phagocytosis is promising as a tool for the assessment of resistance or susceptibility to mastitis.

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4

Bradford, Elaine Alison. « Proposed in vitro model of neutrophil swarming in a chronic, low-level inflammatory state ». Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/102737.

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Chronic, low-grade inflammation is an underlying condition across a globally increasing number of debilitating diseases. These diseases include obesity, atherosclerosis, and diabetes and their resultant low-grade inflammation can be effectivity modeled with low dose stimulants such as lipopolysaccharide (LPS). While the innate immunity plays a significant role in fighting infectious disease, an initial exposure to low dose LPS hinders secondary infection clearance and pre-disposes murine models for fatal sepsis. Neutrophils are the most prevalent circulating innate immune cell and their homotypic aggregation, or swarming, is a key mechanism in clearing pathogens greater than 20 μm in size. We hypothesize that neutrophil swarming ability is altered when in a low dose LPS primed state; potentially leading to an overall altered innate immune response in the face of infection. However, an in vitro model does not currently exist to reliably quantify and compare neutrophil swarms across treatment groups. Here we propose a novel model utilizing fungal zymosan coated beads as a uniform target to which neutrophils may swarm.
Master of Science

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5

Kirsch, Richard. « Characterisation of fibrinogen and fibrin proteolysis by the neutrophil membrane ». Doctoral thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/26928.

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Recent studies have identified a novel 600 kDa neutrophil membrane associated protease which degrades fibrinogen, fibrin and C-reactive protein (CRP) during incubation of these ligands with phorbol 12-myristate 13-acetate (PMA, 5-10 ng/ml) stimulated neutrophils. This proteolysis is predominantly an extracellular event which occurs through a ligand dependent release of this protease from the neutrophil. Degradation products arising from this proteolysis not only become neutrophil associated but influence a number of important processes occurring in inflammation and coagulation. The aim of the present 'study was to purify and further characterize this protease and investigate the location of the neutrophil associated fibrinogen and fibrin degradation products. Whilst enzyme purification procedures were unsuccessful, several observations made during these attempts suggested that the neutrophil membrane associated proteolytic activity displayed similar characteristics to proteases of the azurophil granule. The proteolytic activity of the membrane was concluded from inhibitor profiles, zymography, and the apparent molecular mass values and hydrophobicity of the fibrinogen degradation products that it generated, to be the composite action of the azurophil granule proteases, human neutrophil elastase, cathepsin G and possibly proteinase 3. Electron microscopy analysis of PMA stimulated neutrophils incorporated within fibrin clots revealed morphological changes suggestive of neutrophil degranulation, and the proteolytic activity released by these cells was shown to be identical to that of azurophil granule proteases with respect to the apparent molecular mass values of the fibrin products that it generated. Immunoelectron microscopy revealed minimal internalization of fibrin like material during this process suggesting that neutrophil mediated fibrinolysis under these conditions is predominantly an extracellular event. Immunoelectron microscopy was used to localise fibrinogen degradation products previously reported to be associated with the neutrophil following incubation with fibrinogen. This revealed neutrophil associated fibrinogen products to be intracellular. Internalisation appears to be the result of pinocytosis which is stimulated in the presence of PMA. Although internalisation may be enhanced by an initial interaction of fibrinogen with the neutrophil membrane, a large proportion of uptake occurs via the fluid phase. Both intact and degraded forms of fibrinogen can associate with the neutrophil. Internalised material is rapidly degraded intracellularly into low molecular weight products which are partially released into the surrounding medium. This intracellular degradation, however, contributes minimally to the overall degradation of fibrinogen by neutrophils; the major pathway is extracellular. The demonstration in this· study, that the previously identified fibrinogen- fibrin- and CRP-degrading activity of the neutrophil membrane is due to azurophil granule proteases co-incides with numerous recent reports suggesting that membrane bound forms of these proteases, due to their ability to evade naturally occurring protease inhibitors, are the biologically relevant forms of these proteases. The membrane expression of azurophil granule proteases has recently been shown to be under the control of a variety of inflammatory mediators. Thus, neutrophil mediated degradation of fibrinogen, fibrin and CRP in vivo may be tightly controlled by the regulated expression of azurophil granule proteases on the neutrophil membrane.

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Hoenderdos, Kim. « Modulation of neutrophil degranulation by hypoxia ». Thesis, University of Cambridge, 2015. https://www.repository.cam.ac.uk/handle/1810/247459.

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Neutrophils are key effector cells of the innate immune system. They employ a number of powerful ‘weapons’ to eliminate pathogens, including an array of destructive proteins packaged into distinctive granule subsets. In addition to their microbicidal activity, these granule proteins are capable of causing substantial tissue damage if inappropriately deployed. To mitigate against this possibility, most physiological stimuli induce minimal extracellular degranulation. Sites of inflammation and infection are usually hypoxic, and it has been shown that oxygen depletion compromises neutrophil function by impairing the generation of reactive oxygen species and hence bacterial killing. The key finding reported in this thesis is that hypoxia substantially increases the release of all neutrophil granule subsets, as measured by the release of (active) hallmark proteins (elastase, myeloperoxidase, lactoferrin and matrix metalloproteinase-9). In consequence, supernatants from hypoxic neutrophils induced substantially more damage to lung epithelial cell layers than supernatants from neutrophils cultured under normoxic conditions; this damage was protein- and protease-dependent. This pattern of damage was seen consistently across lung adenocarcinoma-derived epithelial cells, primary immortalised lung epithelial cells, and primary human bronchial epithelial cells grown in physiological air-liquid interface culture. Surprisingly, the mechanism of hypoxia-augmented degranulation was found to be independent of protein synthesis and specifically, of the transcription factor HIF-1α (the ‘master-regulator’ of hypoxic responses); thus, hypoxia did not affect mRNA transcript or protein abundance of the major granule components, and hypoxia mimetics failed to recapitulate the phenotype. Inhibition of the key pathways known to be involved in neutrophil degranulation, including, phosphatidylinositol 3-kinase and phospholipase C, but not calcium flux prevented augmented granule release under hypoxia In conclusion, hypoxia induces a destructive neutrophil phenotype, with increased release of multiple histotoxic proteases. This may contribute to tissue injury and disease pathogenesis in a range of clinically important conditions.

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7

Chen, Justin. « The effect of hyperleptinemia on polymorphonuclear neutrophil-endothelial interactions / ». Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101709.

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Obesity is a growing major public health concern and is associated with various co-morbidities. Given recent evidence of increased bacterial infections in bariatric patients, morbid obesity may adversely affect the immune system. As a pleiotropic pro-inflammatory mediator produced primarily by adipocytes, leptin is a link between metabolism and immunity. Consequently, excessive leptin secretion may hinder the body's ability to defend against bacterial infection. This situation arises in morbid obesity, where chronic hyperleptinemia is observed. We used an in vivo murine model of hyperleptinemia to determine whether abnormal levels of circulating leptin have a detrimental effect on the trafficking of neutrophils, with respect to the number present, their rolling velocity, preadherence, and adherence to the endothelium.
Male CD1 background mice (6-8 weeks) were divided to 3 treatment groups receiving once daily ip injections (1) sham (PBS); (2) low leptin (1mug/g); (3) high leptin (5mug/g). After 7 days of treatment, intravital microscopy was used to visualize post-capillary venule microcirculation of the cremaster muscle in the scrotum. Parameters such as neutrophil rolling, rolling velocity, preadherence, and adherence, were recorded and measured to assess PMN kinetics.
High doses of leptin resulted in increased preadherence and adherence of neutrophils in post-capillary venules. Serum leptin and TNFalpha levels were found not to correlate with this observation; consequently, potential pathways through which leptin increases PMN adhesion could not be elucidated. Conceivably, excessive adhesion could adversely affect neutrophil trafficking by producing a shift towards the marginal pool, limiting their ability to appropriately home into bacterial targets. This could parallel the situation in morbid obesity where high concentrations of leptin are also observed.

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8

Boespflug, Nicholas. « ATF3 regulates neutrophil migration in mice ». University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1382372804.

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9

Lin, Yongqing. « Study of neutrophil diapedesis across a bovine mammary epithelium in vitro ». Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22761.

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Bovine mastitis due to bacterial infection is one of the most costly diseases affecting the dairy industry. The polymorphonuclear neutrophils (PMNs) present in milk have a central protective role against invading pathogens, However, the manner by which PMNs traverse the secretory epithelia and the relationship between PMN diapedesis and the epithelial damage are unclear. This in vitro study investigated the process and rate of bovine PMN transepithelial migration. The bovine mammary epithelial cell line, MAC-T, formed a confluent monolayer with characteristic tight junctions, polarity and functional barrier to the dye trypan blue. In the first series of experiments, neutrophils were added into the upper compartment of the culture insert and stimulated to migrate across the epithelium in an apical-to-basal direction by the addition of Staphylococcus aureus to the lower compartment. Light and transmission electron microscopy revealed the following series of events for PMN transmigration: (1) adherence of PMNs to the surface of the epithelium; (2) projection of pseudopods toward the intercellular junction; (3) migration between adjacent epithelial cells; and (4) re-approximation of epithelial cell membranes and reformation.

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10

Chung, Henry Hung Li. « Engineered Microenvironment for Quantitative Studies of Neutrophil Migration ». Thesis, University of Rochester, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3686523.

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Cell migration is present in virtually all life processes, including fertilization, embryogenic development, immune response, wound healing, and tumor metastasis. To improve the treatment of diseases associated with these various life processes, it is important to understand the underlying mechanisms of cell migration involved. This often requires that we recreate the environment that leads to and supports the continuous migration of cells. Here, we present two engineering approaches toward such a goal, with the additional emphasis that cell migration can be conducted in the absence of fluid flow, a mechanical stimulus that is known to influence cell behaviors. We chose the primary human neutrophil, which is highly motile and sensitive to both fluid flow and chemoattraction, as the model cell type for all our studies.

In the first approach, we used fluid flow to create a linear and time-invariant gradient of chemoattractants to guide the migration of neutrophils. A thin and porous membrane was used to screen off the associated flow forces while still permitting the diffusion of the gradient to the neutrophils. We showed that the membrane-based system is capable of directing neutrophil migration without the bias from fluid flow, and allowed within minutes the exchange of media to label and wash the migrated neutrophils. To assess the reduction of flow forces enabled by the membrane, we developed an analytical model to predict the direction and the magnitude of flow within the system. The validity of the model was verified both experimentally and numerically with particle tracking and computational fluid mechanic (CFM) simulations. We also performed total internal reflection fluorescence (TIRF) microscopy to verify the preservation of the gradient after v its diffusion through the membrane.

In the second approach, we created immobilized gradients of the chemoattractant interleukin 8 (IL-8) and the intercellular adhesion molecule 1 (ICAM-1) in the attempt to guide neutrophil migration. A gradient of soluble factors is first established, and the resulting difference of concentration over space leads to a bias in the binding of the soluble factors unto the substrate, forming an immobilized gradient. The immobilization is mediated by a combination of different physicochemical linkages, including electrostatic attraction, protein/protein interactions, and covalent bonding. We showed through labeling with fluorescent antibody that the number of IL-8 or ICAM-1 immobilized in a given area could be controlled, and varied over distances to form different gradient profiles. We further showed that our immobilization procedure does not affect the ability of IL-8 and ICAM-1 to activate and bind the neutrophils. However, with all the immobilized gradients that we have created so far, none were able to effectively promote the directed migration of neutrophils in long distances. Additional work is therefore required to establish if an immobilized gradient of either IL-8 or ICAM-1 alone can direct the migration of neutrophils in long distances, and if it does, what are the required conditions. Currently, our efforts suggest that the membrane-based chemotaxis system is a more attainable platform for promoting a directed migration that is shear-free.

The presented thesis work offers many potential applications. The membrane-based chemotaxis system, which has the general structure of two compartments separated by a membrane, resembled many physiological structures, including bone marrow, blood vessel, blood-brain barrier, hepatic portal vein, nephron in the kidneys, and alveolus in vi the lungs, and therefore serves as a versatile platform for understanding the transport phenomenon and the biochemical signaling in the aforementioned tissues. With improvements, the membrane-based system can also host larger-scale cell culture for protein production and tissue engineering. The protocols established for the gradient immobilization also provided many valuable references. These include: 1. A 1^st order approximation of the reagents and the times required to fully saturate the substrate to be functionalized. 2. An automated image processing tool to measure the various parameters of cell motility. 3. A statistical framework to detect the presence of a directed migration. In theory, the standard operating procedures established are applicable to the surface functionalization with other peptides and proteins.

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11

Ellard, David. « Psychological stress and neutrophil activation : the potential for tissue damage and disease ». Thesis, Coventry University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271262.

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12

Martinod, Kim Lindsay. « Neutrophil extracellular traps in thrombosis and inflammation ». Thesis, Harvard University, 2014. http://nrs.harvard.edu/urn-3:HUL.InstRepos:13064970.

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Neutrophil extracellular traps (NETs), chromatin released by activated neutrophils, were first described for their antimicrobial properties. NETs have a backbone of DNA and histones lined with microbicidal proteins such as neutrophil elastase. NET release has pathological consequences, particularly within blood vessels where NETs can trap red blood cells and platelets, thus contributing to thrombosis (Chapter 1-Overview). NET formation (NETosis) is an active and coordinated biological process involving many enzymatic components. One enzyme in particular, peptidylarginine deiminase 4 (PAD4), citrullinates histones and is required for chromatin decondensation during NETosis. Neutrophils from PAD4-deficient mice are unable to form NETs. We obtained these mice from our collaborator Dr. Yanming Wang, and thus were able to compare PAD4-/- mice to wild-type (WT) mice in mouse models where NETs are formed. These studies have allowed for investigation of the biological relevance of PAD4 and NETs in vivo in thrombotic and/or inflammatory disease. This dissertation focuses on mouse models of deep vein thrombosis and of sepsis. In venous stenosis, thrombosis is initiated by restricting blood flow in the inferior vena cava (IVC). Here, PAD4-/- mice were greatly protected from thrombus formation (Chapter 2). Leukocyte rolling and platelet plug formation in response to vessel injury were unaffected, indicating that endothelial and platelet activation occurred normally in these mice. The mice did not exhibit any defects in hemostasis, and could be induced to produce deep vein thrombi by infusion of WT neutrophils that formed NETs as a part of the thrombus scaffold. Because there is potential to develop anti-NET therapies in thrombosis, I investigated if NET-deficiency would render mice immunocompromised (Chapter 3). PAD4-/- mice had similar mortality in the cecal ligation puncture model, and they were protected from shock in an LPS sepsis model where NETs are released in the absence of live bacteria. Therapies aimed at NET prevention or destruction would likely be beneficial without compromising host immunity. Thus, in summary, studying PAD4-deficient mice has revealed the impact of NETs in thrombotic/inflammatory disease and identified PAD4 as an attractive therapeutic target.

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13

Patel, Jaimin Mukesh. « Exaggerated neutrophil immunosenescence in sepsis and its potential modification with simvastatin ». Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/5837/.

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Sepsis remains a common reason for hospital admission and is associated with a high mortality especially in the elderly. Neutrophils are one of the primary immune cells involved in the elimination of pathogens; however also contribute to the pathogenesis of multi-organ failure in sepsis. Previous studies have demonstrated an age-related decline in neutrophil migration and phagocytosis suggesting this as a mechanism for the poorer outcomes observed from sepsis in the elderly. Observational studies suggest that HMG-CoA reductase inhibitors (statins) are associated with improved outcomes from sepsis and potentially modulate neutrophil function. This thesis demonstrates that high dose (80mg) simvastatin improved the migration of neutrophils in the healthy elderly without affecting other key neutrophil functions, such as phagocytosis and reactive oxygen species production (ROS). Studies in patients with sepsis, demonstrated that circulating neutrophils displayed features of immune-paresis and failed to migrate, but were activated with increased phagocytosis and ROS. This was accompanied by reduced neutrophil extracellular trap (NET) formation and delayed late apoptosis. The use of in-vitro simvastatin failed to modulate migration, whilst ROS and NET production was reduced by simvastatin. Simvastatin remains a potential immune-modulating drug for treating early infection in the elderly.

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Loitto, Vesa-Matti. « Towards a Refined Model of Neutrophil Motility ». Doctoral thesis, Linköping : Univ, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5142.

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15

Chilcoat, Clayton Douglas. « Protein Kinase A Regulates β2 Integrin Avidity Activation and Subsequent Neutrophil Activation via Modulation of Myosin Light Chain Kinase ». NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-03312005-093042/.

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β2 integrins are adhesion molecules on the surface of neutrophils. Avidity activation of β2 integrins includes transportation of pre-formed integrins to the cell surface and a conformational change in the integrin to a high-binding state. Upon binding ligand, β2 integrins initiate a signaling cascade that results in activation of the neutrophil to a pro-inflammatory state, and the inhibition of this signal can prevent further activation of the neutrophil. cAMP and it effector protein kinase A (PKA) exert a generally inhibitory effect upon neutrophil activation. PKA has been shown to inactivate myosin light chain kinase (MLCK). Myosin light chain (MLC) phosphorylation is crucial for actin-myosin complex formation, which is required for stability and contraction of the actin cytoskeleton in neutrophils as well as β2 integrin-dependent adhesion. We hypothesize that the inhibitory effect of PKA upon neutrophils is due to inhibition of β2 integrin avidity activation resulting in the subsequent inhibition of neutrophil activation. Furthermore we hypothesize that the effect of PKA upon β2 integrin avidity activation is mediated through PKA?s effect upon MLCK. We demonstrate that inhibition of PKA induces β2 integrin-dependent adhesion and that augmentation of cAMP prevented β2 integrin-dependent adhesion and subsequent respiratory burst activity. Further, we demonstrate via flow cytometric detection of antibodies directed against β2 integrins that pharmacologic inhibition of PKA activity results in overall increased β2 integrin expression on the neutrophil surface, as well as increased expression of the activated form of the integrin. This upregulation and activation of β2 integrins due to inhibition of PKA is abolished by pharmacologic MLCK inhibition. Inhibition of MLCK also blocked β2 integrin-dependent neutrophil adhesion achieved by inhibition of PKA, as well as neutrophil migration along towards a PKA inhibitor. These findings demonstrate that PKA regulation of β2 integrin affinity activation and subsequent neutrophil activation is via an MLCK-dependent pathway.

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Thalhofer, Colin Joseph. « Leishmania infantum chagasi induces a dynamic cellular inflammatory response ». Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/1091.

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Leishmania infantum chagasi (Lic) is a pathogenic protozoan parasite and one of the etiological agents of human visceral leishmaniasis (VL). VL is a potentially deadly disease characterized by variable fevers, cachexia, hepatosplenomegaly, and global immune suppression. Many questions regarding the pathogenesis of VL and the mechanisms of host defense during Lic infection remain to be elucidated. The primary focus of this thesis is the relationship between Lic and the mammalian immune system. We studied parasite-host interactions during Lic infection at the molecular, cellular, and organismal level. We generated transgenic parasites that expressed firefly luciferase and/or fluorescent proteins to expand our capacity to detect, observe, and quantify the parasites in a variety of experimental settings with modern analytical methodologies. Using luciferase-expressing Leishmania, we developed an experimental infection model in which parasites were detected and the relative parasite burden in specific anatomical locations could be quantified in a live animal host using bioluminescence imaging. This method allowed the parasite burden to be assessed in the same host throughout the course of infection. Utilizing this model we have made some intriguing observations relating to the kinetics and distribution of the parasite burden over time. The parasite burden was observed primarily in the liver and bone marrow over the first few weeks and then shifts to the spleen and bone marrow. To gain a better understanding of the initial parasite-host immune interactions in vivo, we studied the early inflammatory response after intradermal (i.d.) inoculation. We observed a rapid and abundant influx of neutrophils into the inoculated ears. The neutrophil influx was transient, dose dependent and specific for the local inoculation site. While there was not a significant neutrophil influx into the draining lymph nodes (dLN), there was an increase in the total cellularity and a striking increase in the relative proportion of B cells to T cells over the first week after intradermal parasite challenge. By inoculating transgenic mCherry-Lic we found that neutrophils were the primary parasite-laden host cell in the dermal tissue during the first day, but macrophages harbored most of the parasites by 2 days. Neutrophil depletion using low-dose antibody treatment resulted in a reduced rate of parasite uptake initially at the site of inoculation, but no significant change in the dLN dynamics. We further examined the parasite-host relationship by studying molecular signaling and cellular interactions between Leishmania and human neutrophils. We investigated the nature of the chemotactic activity of Leishmania-conditioned growth medium for human neutrophils by testing physical properties of the activity and ruled out some of the major Leishmania surface molecules as potential candidates. We aim to identify the agent(s) responsible for the activity in on-going studies. To this end, we are collaborating with a group at the NIH and testing biochemical purification/separation samples. We conclude that intradermal Lic challenge induces a rapid innate immune response at the local site of infection, that neutrophils sense Leishmania-derived factors leading to directed migration, and that neutrophils function as a primary site for Leishmania entry into the mammalian host.

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Lee, Jai-Wei 1970. « The effect of recombinant human interleukin-1b and interleukin-8 on bovine neutrophil migration and degranulation / ». Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21587.

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The objective of this study was to investigate the effect of recombinant human interleukin-1beta (rHIL-1beta) and interleukin-8 (rHIL-8) on bovine neutrophil migration and degranulation. An in vitro co-culture system was used to study bovine neutrophil migration. This simulative system allowed studying neutrophil migration across endothelium (bovine aorta endothelial cells), extracellular matrix (ECM), and epithelium (MAC-T) in the correct sequences and directions. Quantification of neutrophil migration was carried out by assaying the activity of myeloperoxidase, a major enzyme of neutrophils. Degranulation of azurophilic, specific, and tertiary granules was studied by measuring releases of myeloperoxidase, lactoferrin, and gelatinase, respectively. The results showed that bovine neutrophils were able to migrate across the simulative co-culture system in response to zymosan activated serum. Recombinant HIL-8 was demonstrated to have a dose-dependent effect on bovine neutrophil migration. Furthermore, rHIL-8 had a dose-dependent effect directly on degranulation of azurophilic and specific granules, but not on tertiary granules. On the other hand, rHIL-1beta only had a significant effect on degranulation of azurophilic granules when the concentration of 100 ng/ml was used. The dose effect of rHIL-1beta on specific degranulation was much stronger. Moreover, the effect of 100 ng/ml rHIL-1beta was augmented when the rHIL-1beta containing solution was preincubated with MAC-T monolayers for four hours. This indicated that MAC-T cells might generate other degranulating factors in response to the stimulation of rHIL-1beta. These MAC-T-derived degranulating factors did not have effect on the release of tertiary granule contents.

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Sapey, Elizabeth. « Inflammation and neutrophil recruitment in ageing subjects and patients with chronic obstructive pulmonary disease ». Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/1211/.

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The neutrophil is central to the development of COPD. To enter lung, neutrophils must migrate accurately from the circulation to inflamed tissue. It is unclear which migratory stimuli are important and whether COPD neutrophils vary in their migratory behaviour, either to controls or patients with similar lung disease. COPD sputum and plasma samples were collected on 11 occasions over one month. Significant correlations were demonstrated between the inflammatory biomarkers and between inflammatory biomarkers and markers of disease. IL-8 correlated most strongly both with other inflammatory mediators, neutrophil counts and indices of disease. Neutrophils from healthy older subjects migrated with maintained speed but reduced accuracy to IL-8. Differences could not be accounted for by surface receptor expression or shedding, but inhibition of CXCR2 gave young neutrophils and old migratory phenotype, suggesting altered downstream signalling. COPD neutrophils migrated with increased speed and reduced accuracy compared with control groups. They formed less pseudopodia when migrating, and had reduced surface expression of CXCR1 and CXCR2. Inhibitory studies suggested that CXCR2 was the predominant receptor in migration to biological samples. Treating COPD cells with a PI3 Kinase inhibitor differentially altered their migration, reducing speed but increasing accuracy, so that cells now resembled those from controls.

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Van, Ziffle Jessica Ann Grant. « Src-family and Syk tyrosine kinases are required for neutrophil effector responses to infection and inflammation ». Diss., Search in ProQuest Dissertations & ; Theses. UC Only, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3390082.

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Abdulla, Salima Abubaker. « Developmental innate immunoinsufficiency : comparison of term neonatal neutrophil proteinases and complement component levels relative to adults ». Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/45061/.

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Despite current improvement in newborn care, infection is still a common cause of neonatal morbidity and mortality. Innate immunity is the first line of defence against pathogens particularly in newborn infants. Quantitative and functional deficit in non-cellular (complement system) and cellular (neutrophils) arms of innate immune system is believed to contribute to neonatal susceptibility to infection. Neutrophil granule subsets contain a variety of proteases, including elastase, cathepsins, MMP-9 and proteinase 3 along with different granule markers and receptors. This thesis demonstrated that normal term neonatal neutrophils express more proteinase 3 and CD177 on their surface while no differences were found in expression of markers CD35, CD66b and CD63 (representing the secretory, secondary and primary granule subsets, respectively). Cord neutrophils contain more PR3 than adult cells but the proportion of PR3 released by cord and adult neutrophils was similar. In contrast, neonatal neutrophils contained only half of the cathepsin G and elastase functional activity of adult neutrophils. Bronchoalveolar lavage fluid studied from preterm infants ventilated for respiratory distress demonstrated higher proteinase 3 concentrations in lavage samples from infants who went on to develop chronic lung disease than in infants with resolved respiratory distress syndrome. Concentration of proteinase 3 in lavage samples was significantly higher than MMP-9 and elastase levels, suggesting that it may have an important role in disease pathogenesis. Complement is an equally important component of the innate immune system that plays a central role in recruiting and activating neutrophils, as well as being directly bactericidal through the terminal lytic pathway. Analysis of neonatal complement system revealed that Complement function and terminal components levels particularly C9 are deficient (except C7) in healthy term newborn infants compared to normal adults. Bactericidal capacity of a selection of neonatal sera was tested along with adult sera against four serovars of Ureaplasma parvum, a potentially important perinatal pathogen. Results showed impaired bactericidal capacity of neonatal serum compared to adult serum especially against SV1. Ureaplasma SV3 was the most serum sensitive serovar whereas killing of the resistant serovars SV6 and 14 could not be induced by supplementation of the deficient components C6, C8 and C9.

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Atkinson, Yvelle Hope. « Regulation of neutrophil functions by tumor necrosis factor-alpha / ». Title page, contents and summary only, 1989. http://web4.library.adelaide.edu.au/theses/09PH/09pha878.pdf.

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Sekar, Padmapriya. « The Effects of Key Motility and Chemotaxis Genes on Borrelia burgdorferi Dissemination and Evasion of Immune Clearance in Murine Tissues ». University of Toledo Health Science Campus / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1430936396.

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Pankhurst, Tanya. « Heterogeneity of injury in vasculitis : influence of anti neutrophil cytoplasm antibody IgG subclass and endothelial susceptibility ». Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/718/.

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This study examined IgG subclass in ANCA associated vasculitis and glomerular endothelial cell (GEC) phenotype predisposes to injury. Using the flow model, interaction of neutrophils with normal immunoglobulin subclasses was compared to interaction with subclasses of ANCA IgG. Neutrophils were captured by normal IgG3>IgG1>IgG2/IgG4. Blockade of CD32 affected IgG3, CD16, IgG1/2. Neutrophils exposed to soluble ANCA IgG1/3 adhered to cytokine-activated endothelial cells, as did IgG4, not previously thought to bind constitutively expressed CD16/CD32. Fc blockade reduced binding. GEC were compared with human umbilical vein endothelial cells. Surface VCAM-1 was reduced on GEC and GEC demonstrated reduced leukocyte capture. RNA array analysis demonstrated a reduction in the GEC gene responsible for post translational modification of VCAM-1 to a sialoglycoprotein. VCAM-1 expression by GEC may be a protective mechanism to reduce inflammatory responses, potentially disrupted in disease. ANCA subclass and endothelial phenotype are important vasculitis pathogenesis: this may be useful in designing targeted therapy reducing overall immunsuppressive load. Additionally modification of specific adhesion molecule profiles on endothelial cells may enable alteration of conditions of one vascular bed whilst reducing impact on unaffected sites.

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Rosetti, Sciutto Florencia. « Neutrophil human Fcg Receptor IIA and the b2 integrin Mac-1 cross-talk in autoimmune disease ». Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11461.

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Systemic lupus erythematosus (SLE) is a chronic multiorgan autoimmune disorder characterized by abundant immune complex (IC) deposition, with nephritis being a major cause of morbidity and mortality. Yet, IC deposition alone is not sufficient for disease development suggesting that additional factors dictate the propensity for developing target organ injury. Genome-wide association studies have identified polymorphisms in the leukocyte integrin Mac-1 (CD11b/CD18, ITGAM) that associate with lupus nephritis. Although Mac-1 promotes inflammation by triggering leukocyte recruitment and cytotoxic functions, there is emerging evidence that it may also serve protective roles under certain conditions. We demonstrate that Mac-1 deficiency in the context of the uniquely human FcgRIIA a receptor that binds IgG-IC, promotes susceptibility to lupus nephritis in two independent animal models. Analysis of renal tissue and intravital microscopy revealed that Mac-1 modulates neutrophil recruitment by FcgRIIA. The SLE-associated variant of Mac-1 rs1143679 (R77H), results in reduced Mac-1 functions, but the underlying mechanism remains undefined. CD18 integrin mediated adhesion is a multistep process that begins with affinity changes for ligand via transmission of allosteric signals. Moreover, mechanical forces (e.g. shear flow) paradoxically increase the lifetime of integrin-ligand bonds, referred to as "catch-bonds". Here, we show that expression of Mac-1 R77H on neutrophils, and blocking antibodies to the extracellular b-propeller domain in which it resides, markedly impairs Mac-1 adhesion to ligand under shear flow. R77H expressing cells exhibit a shift in equilibrium towards a bent conformation, a lower affinity and on- and off- rate for ligand and an inability to form catch-bonds. Additional mutants and activating antibodies reveal that R77H prevents allosteric signal transmission to the aI-domain required for productive ligand binding.

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Llewellyn, David C. C. « Assessment of anti-merozoite antibody function in the context of blood-stage malaria vaccine development ». Thesis, University of Oxford, 2014. https://ora.ox.ac.uk/objects/uuid:72e325e5-504c-480a-8b89-6a3ecb73f699.

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In regions endemic for malaria, natural exposure results in an acquired immunity which protects individuals from severe disease. However, no vaccine against the blood-stage of malaria, against which naturally-acquired immunity is targeted, currently exists that is capable of emulating, or out-performing, natural protection. To rationally direct the next generation of blood-stage malaria vaccine development, a greater understanding of the immunological mechanisms involved in clinical protection is required. To date, the assessment of naturally-acquired and vaccine-induced immunity to the blood-stage of malaria has suffered from a paucity of in vitro immunological assays that are both robust and reproducible, whilst allowing for assessment of anti-parasitic activity induced by antibodies, either alone, or in conjunction with immune cells. Thus this Thesis describes the development of the antibody-dependent respiratory burst (ADRB) assay, for assessment of blood-stage immunity against Plasmodium falciparum, as well as the Duffy antigen receptor for chemokines (DARC) â Duffy binding protein (DBP) binding inhibition assay, for assessing antibody mediated immunity to P. vivax. A reproducible and standardised assay of ADRB activity was developed here and applied to studies of immunity in both mice and humans. ADRB activity, which assesses antibodies' ability to activate oxidative burst in neutrophils via Fc receptor (FcR)-dependent pathways, was shown to associate with clinical protection in a cohort from Mali where FcR-independent immunological assays, such as the assay of growth inhibition activity, did not. This work thus elucidates the importance of FcR-dependent immunity to P. falciparum malaria and establishes the ADRB assay as a useful tool for future vaccine development. In addition, the DARC-DBP binding inhibition assay was established and utilised to assess inhibitory activity of antibodies induced in the first Phase I clinical trial of this antigen. Results identify the need for significant improvements in vaccine design, and show the utility of the assay as a tool for assessing future blood-stage vaccine development efforts against this neglected parasite.

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Clark, Heather Lynn. « Neutrophils, Nutritional Immunity and NETs : Host-Pathogen Interactions in Aspergillus fumigatus Infection ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1480451373752014.

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Dürr, João Walter. « Associations between neutrophil potential phagocytic capacity in proven bulls and traits of economic importance in their daughters ». Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22728.

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Neutrophil potential phagocytic capacity (NPPC), measured on 25 AI Canadian Holstein bulls, was investigated for evidence of association with production and type traits, SCC, and survival in dairy cows. Bulls were ranked based on different degrees of NPPC (Uptakes of 0, 1, 2, and 3 or more latex beads), using the solutions coming from an animal model. A total of 42,103 first lactation records, collected from 1985 through 1993 in 2,919 Quebec dairy herds, were used to obtain EBV's for SCC and for log SCC (LogSCC) for 697 sires. Correlations between NPPC measurements and somatic cell EBV's were null. Canadian official ETA's for type traits related with mammary system had a tendency of being positively correlated with higher NPPC and negatively with Uptake-0. Canadian official ETA's for production traits were negatively correlated with higher NPPC and positively with Uptake-0. A total of 17,202 first lactation records of daughters of the 25 AI bulls were used to study the effect of NPPC and log SCC on survival in dairy cows. Survival after first lactation was more closely related to sires' NPPC-EBV's than to LogSCC-EBV.

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Davis, Richard Elliot. « Neutrophil responses to infection with leishmania parasites : MHC class II-expression and parasite life-stage interactions ». Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2200.

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The vector-borne protozoan Leishmania spp. cause the spectrum of disease known as leishmaniasis in human and animal hosts. The most common manifestations of leishmaniasis are the chronic, ulcerative skin disease cutaneous leishmaniasis (CL), and the more serious visceral leishmaniasis (VL) in which parasites take up residence in internal organs, causing death if not treated. The role of neutrophils (PMNs) in the immune response to CL and VL is unclear. It is s generally thought that PMNs are only a short-lived effector cell, and have been disregarded as playing a role in chronic Leishmania spp. infection. As both CL and VL are diseases characterized by increased inflammatory immune mediators, we hypothesized that PMNs from human or animal models of chronic leishmaniasis would display different properties from PMNs from healthy controls. We found in a subset of CL and VL patients circulating PMNs expressing HLA-DR, the human form of MHC class II, a molecule thought to be restricted primarily to professional antigen cells. When we examined PMNs recruited to CL skin lesions in human patients, or similar lesions in experimental murine model of CL, we found significantly increased MHC class II+ PMNs. Circulating HLA-DR+ PMNs also expressed the co-stimulatory molecules CD80, CD86 and CD40. While this suggested an antigen-presenting cell-like phenotype by these HLA-DR+ PMNs, compared to conventional HLA-DR- PMNs, HLA-DR+ PMNs showed not only a neutrophil-like appearance and function, but in fact increased activation, degranulation, intracellular MPO and phagocytosis of parasites and zymosan particles. Incubation of healthy control whole blood with inflammatory cytokines resulted in increased HLA-DR+ PMNs and the presence of hladrb1 mRNA, suggesting a connection between neutrophil “priming” and upregulation of HLA-DR. In addition to HLA-DR+ PMNs in CL patients, we also identified the presence of so-called “low-density” neutrophils (LD-PMNs). These neutrophils, which are enriched in low-density fractions following centrifugation of blood over a density gradient, are reported in numerous disease states, including cancer, HIV, and systemic lupus erythematosus. In some disease states, LD-PMN are reported to be immunosuppressive toward T cell activation and proliferation. However, LD-PMNs from leishmaniasis patients showed no evidence of immunosuppression. Additionally, we found that LD-PMNs show significantly increased surface expression of MHC class II, suggesting a heretofore unappreciated connection between these atypical neutrophil phenotypes. We also investigated the in vitro interactions with different Leishmania infantum life-stages, both those that cause acute infection (promastigotes) and amastigotes, which are found during chronic stages of the disease. We found that PMNs are readily infected by all L. infantum life-stages, but that amastigotes may have different methods of interacting with PMN surface receptors and are better equipped to avoid PMN anti-microbial responses. These data suggest that circulating PMNs in chronic leishmaniasis may have unique phenotypes and interact differently with the Leishmania spp. life-cycle present during chronic infection. Further investigation of the role of PMNs and atypical PMN phenotypes in chronic disease may help identify new immunomodulatory roles for this cell type.

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DeLyria, Elizabeth S. « Acute Phase T Cell Help in Neutrophil-Mediated Clearance of Helicobacter pylori ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1259784649.

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Johnson, Lauren Elizabeth. « The pmrHFIJKLM Operon in Yersinia pseudotuberculosis Enhances Resistance to CCL28 and Promotes Phagocytic Engulfment by Neutrophils ». BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5983.

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Yersinia pseudotuberculosis is a foodborne pathogen that is the ancestral strain to Yersinia pestis, the causative agent of Plague. Y. pseudotuberculosis invades a host through the intestinal epithelium. The bacteria resist mucosal innate immune defenses including antimicrobial chemokines and phagocytic cells, and replicate in local lymph nodes. They cause Tuberculosis-like symptoms, including necrosis of local tissue and granuloma formation. Like all bacteria, Y. pseudotuberculosis has a net negative charge, which contributes to its susceptibility to some cationic antimicrobial peptides. Y. pseudotuberculosis is able to reduce this negative charge by adding 4-amino-4-deoxy-L-arabinose (L-Ara4N) to the lipid A portion of lipopolysaccharide. The production and addition of the L-Ara4N is coded for by the pmrHFIJKLM (pmrF) operon. A previous study has shown that the Y. pseudotuberculosis pmrF operon is important for resistance against polymyxin, but is not important for virulence in mice. Several previous reports have shown a strong influence of growth temperature on resistance to antimicrobial peptides and pmrF expression in pathogenic Yersinia species, but these studies also suggest significant variability between species, and even between strains of individual species. In particular, the regulation of the Y. pseudotuberculosis pmrF operon and its effect on bacterial interactions with mucosa-associated antimicrobial chemokines and neutrophils is not understood. In these studies, we investigated the environmental influences on pmrF expression in Y. pseudotuberculosis. We found that the promoter activity of the pmrHFIJKLM operon is increased at lower temperatures (21ºC) and in the presence of human serum. A ΔpmrI mutant strain of Y. pseudotuberculosis defective for addition of L-Ara4N was found to be more susceptible to killing by the antimicrobial chemokine CCL28 compared to wild-type. This suggests that this gene is important in the bacterial defense against antimicrobial chemokines. However, when the ΔpmrI mutant strain was exposed to human neutrophils, there was a decrease in phagocytosis as compared to wild-type bacteria. Our results suggest that the regulation of L-Ara4N modifications in Yersinia is more complex than previously appreciated and varies between species. Addition of L-Ara4N to Y. pseudotuberculosis appears to enhance resistance to some antimicrobial peptides like CCL28 and promote greater phagocytic engulfment by neutrophils. These opposing effects may partly explain why there is no net apparent survival defect in mutants lacking the pmrF operon during infection.

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Rowe, John Christopher. « Targeting Neutrophils to Improve Protection by Sublingual Vaccines ». The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1612190976457585.

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Windsor, Alastair Colin James. « An investigation of the role of tumour necrosis factor alpha in gram negative sepsis : defining a link between sepsis and neutrophil mediated acute lung injury ». Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306899.

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Zhang, Nan. « Identification of Receptors and Signaling Pathways Involved in Borrelia burgdorferi-Elicited IL-10 and Potential Therapies for Lyme disease ». University of Toledo Health Science Campus / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=mco1405591577.

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Morath, Jakob Paul. « Transaldolase 1 is required for Neutrophil Extracellular Trap (NET) Formation ». Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21426.

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Transaldolase-Mangel (TALDO) ist ein extrem seltener, angeborener Stoffwechseldefekt, von dem weltweit nur 34 Fälle bekannt sind. Der Defekt geht auf den Verlust des Enzyms Transaldolase 1 aus dem nicht-oxidativen Pentosephosphat-Weg (nicht-oxPPW) zurück und äußert sich in einem weiten Spektrum klinischer Symptome. Die schwerwiegendsten Folgen sind Leber- und Nierenmangelfunktionen, die zum sehr frühen Tod führen können. Desweiteren leiden 15 % der Patienten an wiederkehrenden Infektionen. Neutrophile Granulozyten (Neutrophile) sind die häufigsten weißen Blutkörperchen im Menschen und essentiell für die angeborene Immunantwort gegen Infektionserreger. Ich habe hier funktionale Aspekte von TALDO-Neutrophilen untersucht. Der oxidative Pentosephosphat-Weg (oxPPW) stellt das Reduktionsäquivalent NADPH bereit, welches indirekt für die Entstehung von reactive oxygen species (ROS)-abhängigen Neutrophil Extracellular Traps (NETs) verantwortlich ist. Der Beitrag des nicht-oxPPW zur ROS-abhängigen NET-Bildung ist bislang nicht bekannt. In dieser Arbeit konnte ich für Neutrophile aus drei TALDO-Patienten eine jeweils komplett abwesende Entstehung ROS-abhängiger NETs und einen deutlich verringerten oxidativen Burst nach PMA-Stimulation zeigen. Um diese Beobachtungen in einem unabhängigen Modelsystem zu bestätigen, habe ich mit Hilfe des CRISPR-Cas9-Systems, ‚knock-out‘ Mutanten von Transaldolase 1 und dessen Partnerenzym Transketolase in der Neutrophil-ähnlichen Zelllinie PLB-985 hergestellt. Die dergestalt genetisch manipulierten Zellen waren nicht mehr zu PMA-induziertem Zelltod in der Lage. Dies ist somit der erste genetische Beweis für die Abhängigkeit des oxidativen Burst und der Bildung von NETs vom nicht-oxPPW. Diese Erkenntnis trägt zum einen zum mechanistischen Verständnis der NET-Entstehung bei und liefert zum anderen eine potentielle Erklärung für einige der bei TALDO beobachteten Symptome. Desweiteren wurden einige der metabolischen Erfordernisse für die Bildung von NETs mit Hilfe von Inhibitoren untersucht. Die erhaltenen Erkenntnisse zeigen, dass das initiale Maximum des oxidativen Bursts für NET-Bildung unerheblich ist und vielmehr die ROS-Generierung nach ca. 50 Minuten entscheidende Bedeutung für diese hat.
Transdaldolase 1-deficiency (TALDO) is a rare genetic disease with only 34 described cases globally. Transaldolase 1 is part of the non-oxidative pentose phosphate pathway (PPP) and its deficiency results in many clinical symptoms including kidney and liver failure, which can lead to early child-mortality. Some of these patients suffer from recurrent infections, for example in the respiratory tract. Neutrophils are the most abundant white blood cells and essential for the innate immune defence against bacterial and fungal pathogens. The PPP generates reduced NADPH that is crucial for the generation of superoxide by the NADPH oxidase NOX2. In turn, NOX2 is essential for neutrophil extracellular trap (NET) formation. NETs occur through the neutrophil-specific cell death netosis and consist of chromatin decorated with granular proteins. Here I report that neutrophils of three TALDO patients did not make NETs. Deletion of transaldolase 1, and its partner enzyme transketolase, in the neutrophil-like PLB-985 cell line reduced ROS generation and cell death. This confirms that transaldolase 1 is required for NET formation. We present, to the best of our knowledge, the first genetic evidence that the non-oxidative PPP is required for ROS generation and NET formation. Furthermore, some of the metabolic requirements for NET formation were assessed. The obtained data indicate that the initial peak of the oxidative burst is irrelevant for NET formation but the ROS generation after 50 minutes on the contrary has crucial significance.

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PELLEGRINO, GABRIELLA. « PHENOTYPIC AND FUNCTIONAL CHARACTERIZATION OF HUMAN NEUTROPHIL SUBSETS IN PATIENTS WITH COLORECTAL CANCER AND INFLAMMATORY BOWEL DISEASES ». Doctoral thesis, Università degli Studi di Milano, 2017. http://hdl.handle.net/2434/485079.

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Neutrophils play a critical role in the maintenance of intestinal homeostasis while, in pathological conditions, these cells, together with macrophages, T and B lymphocytes, infiltrate the lamina propria where they exert their functions. In murine models of intestinal inflammation and cancer, a change in neutrophils phenotype and its possible functional consequence has already been described while, in humans, there are limited data. Whether mucosal neutrophils play different functional roles in inflammatory bowel diseases (IBD) and colorectal cancer (CRC) is still debated. Here, we report the identification of two populations of human neutrophils (CD15+/CD66bhigh and CD15int/CD66bint) differentially expressed in the peripheral blood and in the gut tissue of IBD and CRC patients. We extensively characterized them phenotipically and we evaluated if the differences observed among groups of patients might correlate with pharmacological treatments; we also evaluated if these circulating and tissue-infiltrating cells also showed a skewing in the functional phenotype towards a more inflammatory or tolerogenic (N1/N2) phenotype. Finally, we evaluated cytokine and ROS production by freshly isolated neutrophils in response to intestinal bacteria.

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Zukauskas, Andrew. « The Role of Eukaryotic ABC-Transporters in Eliciting Neutrophil infiltration during Streptococcus pneumoniae infection ». eScholarship@UMMS, 2018. https://escholarship.umassmed.edu/gsbs_diss/982.

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Streptococcus pneumoniae (S. pneumoniae) is a Gram-positive, encapsulated bacterium capable of causing significant morbidity and mortality throughout the world. A hallmark of S. pneumoniae infection is infiltration of neutrophils (PMNs) that assist in controlling the spread infection but may also contribute to pathology. Paradoxically, studies have shown that limiting PMN infiltration into the lumen of the lung during infection actually betters clinical outcome in experimental S. pneumoniae infection. The final step in PMN luminal trafficking is a Hepoxilin A3 (HXA3)-dependent migration across the pulmonary epithelium. HXA3 is a PMN chemoattractant that forms gradients along the polarized epithelial face, drawing PMNs from the basolateral to the apical surface during proinflammatory responses. HXA3 requires assistance of an integral- membrane protein transporter to escape the cell and form the gradient. The pulmonary HXA3 transporter is currently unidentified. In this work, we identify the pulmonary HXA3 transporter as the ATP-Binding Cassette Transporter (ABC transporter) Multi-drug Resistance Associated Protein 2 (ABCC2, MRP2). We demonstrate that MRP1 and MRP2 are divergent ABC- transporters that control transepithelial PMN migration through efflux of a distinct anti-inflammatory substance and the pro-inflammatory HXA3 in the context of Streptococcus pneumoniae infection. Enrichment of MRP2 on the plasma membrane requires detection of the bacterial virulence factors pneumolysin (PLY) and hydrogen peroxide. PLY and hydrogen peroxide not only coordinate MRP2 apical membrane enrichment but also influence HXA3-dependent PMN transepithelial migration. They influence migration through stimulation of epithelial intracellular calcium increases that are crucial for HXA3 production as well as MRP2 translocation to the plasma membrane. PLY and hydrogen peroxide are not sufficient in their signaling alone, however, and require at least one additional bacterial signal to induce HXA3/MRP2 proinflammatory activities.

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Arnett, Eusondia A. « Neutrophil products inhibit LLO secretion and activity, and Listeria monocytogenes intracellular growth ». The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1374064718.

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Van, Andre P. « Characterisation of chromatin extracellular traps in rainbow trout (Oncorhynchus mykiss) ». Thesis, University of Stirling, 2018. http://hdl.handle.net/1893/27930.

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One of the greatest challenges in finfish aquaculture is combating losses caused by infectious bacterial diseases, and a better understanding of the interactions between the host immune system and pathogens is essential for developing new methods to manage infections and outbreaks. Extracellular traps (ETs) are decondensed nuclear chromatin released by neutrophils into the extracellular matrix that can ensnare and kill microbes. Since the discovery of ETs in humans, these innate immune effectors have been characterised across the animal kingdom, including in some fish species, though their existence the salmonids has yet to be confirmed. Therefore, the aim of this thesis was to confirm and characterise the release of ETs in the rainbow trout (Oncorhynchus mykiss) and investigate the interaction of these structures with fish pathogenic bacteria. To do this, a triple-layer Percoll gradient technique was employed to give highly enriched cell suspensions of polymorphonuclear cells (PMNs) derived from head-kidney tissue preparations. Treatment of PMN-enriched cell suspensions with the nucleic-acid-specific stain, SYTOX Green, revealed the presence of ET-like structures that had been released without stimulation. These ET-like structures were confirmed by immunostaining techniques to contain the diagnostic proteinaceous markers of ETs: neutrophil elastase, myeloperoxidase and the H2A histone. Previously characterised inhibitors and inducers of ET release from phagocytic immune cells in other animals confirmed that calcium ionophore (CaI), flagellin, and cytochalasin D shared similar activities for ET-release by rainbow trout PMNs. However, interestingly, as the common ET-inducer phorbol-myristate acetate (PMA) and ET-inhibitor diphenyleneiodonium (DPI) did not exert their expected potency in ET release assays with the PMNs, perhaps indicating that these fish cells are less dependent on NADPH oxidase signalling for ET release compared to mammals and most invertebrate species. The PMN-derived ETs were demonstrated to bind to and trap the extracellular nuclease-deficient bacterial fish pathogen, Vibrio anguillarum (Vib 87) when co-cultured. Finally, extracellular nuclease activity produced by a V. anguillarum isolate (Vib 6) during culture was able to degrade ETs released by rainbow trout PMNs in a dose-dependent manner. Moreover, viable colony counts, fluorescent and phase contrast microscopy demonstrated that V. anguillarum Vib 6 eluded trapping by ETs, while an extracellular nuclease-deficient isolate did not. These observations are consistent with the suggestion that nucleases are a microbial virulence factor during host infection. Confirming the existence and antimicrobial potential of extracellular traps released by rainbow trout PMNs may provide a platform towards the development of novel therapeutics to reduce mortalities in finfish aquaculture caused by infectious microbial pathogens.

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Hillian, Antoinette D. « Interleukin-8 as a genetic modifier and pharmacologic target for cystic fibrosis pulmonary disease ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1244177510.

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Karmakar, Mausita. « INFLAMMASOME DEPENDENT AND INDEPENDENT IL-1BETA PROCESSING BY NEUTROPHILS DURING BACTERIAL KERATITIS ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1396544303.

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Persson, Alexander. « Apoptotic neutrophils enhance the immune response against Mycobacterium tuberculosis ». Doctoral thesis, Linköpings universitet, Medicinsk mikrobiologi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-51467.

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Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, a disease that for years was considered to belong of the past, but tuberculosis is back causing over 2 million deaths per year. The infection can be dormant for decades and an active immune response can prevent the infection from progressing into active disease. However, the HIV/AIDS epidemic has caused an alarming rise in tuberculosis cases. The main infectious route for Mtb is through the airways into the lungs, where they encounter alveolar macrophages. Mtb are phagocytosed by these macrophages, but instead of being killing within the phagosome, Mtb modulates the cell to become a host in which the bacteria thrive. The lack of capacity to eradicate the infection stimulate cells of the immune system to gather around infected macrophages and form a granuloma that walls off the infection. Within this granuloma, Mtb can wait silently and later progress into active disease. However, only a fraction of exposed individuals develop disease, indicating that initial eradication of Mtb infections is possible. Such immediate response must be directed by the innate immunity comprised of phagocytes such as neutrophils (PMNs) and non-activated macrophages. Upon Mtb infection, macrophages become anergic and PMNs enter apoptosis. PMNs have a short lifespan and are cleared by neighbouring phagocytes, a mechanism described to resolve the inflammation and modulate tissue regeneration. We found that Mtb-induced apoptosis in PMNs was not dependent on phagocytosis of the bacteria, indicating that Mtb have the capacity to induce apoptosis in multiple PMNs. Complement-mediated phagocytosis induce survival signals such as Akt in PMNs, but despite this, complement-opsonized Mtb was able to override the anti-apoptotic activation in the cells. Since phagocytes clear apoptotic cells, we investigated how clearance of Mtb-induced apoptotic PMNs affected macrophages. We found that Mtb-induced apoptotic PMNs inflicted pro-inflammatory activation of the macrophages that cleared them. In addition, this activation was mediated by Hsp72 released from the Mtb-induced apoptotic PMNs. Furthermore, apoptotic PMNs can work in synergy with phagocytosed Mtb to activate macrophages and enhance intracellular killing of Mtb. Since dendritic cells are important for the regulation of immunity, we investigated whether Mtb-induced apoptotic PMNs affected the inflammatory response and maturation of dendritic cells. We found that Mtb-induced apoptotic PMNs trigger dendritic cells to enter a mature state able to activate naïve T-cell proliferation. We propose that infected apoptotic PMNs is a potent activator of the inflammatory response during infections. Taken together, PMNs not only kill their share of pathogens but also modulate other immune cells, thereby forming a link between the early innate and the adaptive immune response during microbial challenge with Mtb.

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Kesteman, Nicolas. « Etude de la migration des neutrophiles dans les organes lymphoïdes ». Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210651.

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Le rôle des neutrophiles dans la réponse immunitaire innée est bien connu. Ils résident dans le sang et ont une durée de vie limitée à quelques heures. Suite à une infection, ils quittent le flux sanguin et se dirigent vers les sites inflammatoires en réponse à des chimiokines produites par des cellules endothéliales et des fibroblastes. Au niveau du site d’inflammation, les neutrophiles phagocytent et éliminent les pathogènes extracellulaires, et produisent des cytokines inflammatoires.

Des travaux récents montrent que les neutrophiles peuvent également jouer un rôle dans l’immunité adaptative. En effet, ils ont la capacité de transporter des antigènes vers les ganglions lymphatiques, d’induire la différenciation des lymphocytes et d’influencer la réponse immune adaptative par la production de cytokines.

La fonction des neutrophiles dans l’induction et/ou la régulation de la réponse adaptative requiert l’interaction entre ceux-ci et d’autres populations cellulaires, telles que les cellules dendritiques et les lymphocytes.

Nous avons donc examiné la localisation des neutrophiles au niveau de la rate dans des conditions basales ou inflammatoires. D’une manière générale, nos résultats montrent que, en cas d’infection, les neutrophiles migrent vers la pulpe blanche de la rate et se localisent en contact étroit avec les lymphocytes T. Ce phénomène de migration est dépendant des molécules CD14 et MyD88 et corrèle avec l’augmentation de l’expression des chimiokines CXCL1 et 2, ainsi qu’avec la diminution de l’expression du récepteur CXCR2 à la surface des neutrophiles.

Cependant, au niveau de la cavité péritonéale, le recrutement des neutrophiles est augmenté en absence de la molécule CD14. Nos résultats montrent que la migration des neutrophiles, dans les organes lymphoïdes et non lymphoïdes, est dirigée par des mécanismes différents.

Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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Ozment-Skelton, Tammy Regena. « Dectin-1 Expression is Altered by Fungal Infection, Polymicrobial Sepsis, and Glucan Administration ». Digital Commons @ East Tennessee State University, 2006. https://dc.etsu.edu/etd/2239.

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Glucans are fungal cell wall PAMPs that promote survival in polymicrobial and candidal sepsis. Dectin-1 is the primary PRR for glucans. The goals of the present study were to characterize 1) the effects of fungal infection on Dectin-1; 2) the effects of polymicrobial sepsis in the presence and absence of glucan on Dectin-1; 3) the effects of systemic administration of glucans on Dectin-1; and 4) the intracellular trafficking of glucans. Mice were either systemically infected with Candida albicans, or made septic by CLP with and without glucan phosphate (GP) injection, or injected with GP. Flow cytometry was performed to assess cell surface Dectin-1 expression. C. albicans sepsis resulted in an increase in the percentage of Dectin-1 positive (Dectin+) blood and splenic leukocytes by increasing the percentage of neutrophils. C. albicans infection increased the percentage of Dectin+ splenic T cells. CLP decreased the percentage of highly Dectin-1 positive leukocytes in the blood by decreasing the percentage of Dectin+ neutrophils. GP treatment in sepsis further decreased the percentages of Dectinhigh blood leukocytes and Dectin+ neutrophils. CLP decreased the percentage of Dectin+ splenic leukocytes by decreasing the percentage of splenic macrophages. GP administration to CLP mice further decreased the percentage of Dectin+ splenocytes by decreasing the percentage of Dectin+ macrophages. Administration of GP resulted in a prolonged decrease in the percentage of Dectinhigh blood leukocytes. The changes in Dectin-1 expression with GP were because of decreases in the percentage of Dectin+ neutrophils and monocytes. In the trafficking studies, macrophages were incubated with fluorescent labeled glucans and then stained for intracellular organelles and signal transduction molecules. Cells were imaged using confocal microscopy. GP is internalized by clathrin and trafficked to the Golgi apparatus. GP internalization is regulated but not dependent on caveolin-1. GP co-localized with SRA, TLR2, and PI3K/p85. The trafficking of laminarin and particulate glucan is similar. We speculate that loss of cell surface Dectin-1 may be important in the protection conferred by glucans in sepsis. Additionally, intracellular trafficking and interaction with signaling components may be important steps in modulation of cellular function by glucan-pattern recognition receptor complexes.

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Yao, Yi. « Sequential Priming of Neutrophils ». University of Toledo Health Science Campus / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=mco1389612809.

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Stringer, Rebecca Elizabeth. « Endogenous and activated protein synthesis in human neutrophils ». Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386847.

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Perskvist, Nasrin. « Interaction between Mycobacterium tuberculosis and human neutrophils / ». Linköping : Univ, 2001. http://www.bibl.liu.se/liupubl/disp/disp2001/med679s.pdf.

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Cavalcanti, Danielle Maia de Holanda. « Papel dos glicocorticóides endógenos na expressão de moléculas de adesão envolvidas na interação leucócito-endotélio ». Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/9/9141/tde-05012018-094826/.

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Os glicocorticóides endógenos (GCen) são moduladores importantes das reações inflamatórias, com papel em diferentes aspectos do processos. Neste contexto, tem sido demonstrado que os GCen controlam a migração de leucócitos para os focos de lesões, e um dos mecanismos propostos tem sido o efeito inibitório sobre os fenômenos de interação leucócito-endotélio. Uma vez que as moléculas de adesão medeiam os processos de interação celular, tem sido evidenciado que os GCen controlam, direta ou indiretamente, a expressão destes receptores nas membranas celulares na vigência de estresse de diferentes origens. No entanto, a literatura ainda é fragmentária e controversa quanto aos mecanismos exatos desta interferência. Desta forma, este trabalho tem por objetivo investigar o papel dos GCen sobre a expressão de moléculas de adesão envolvidas na interação leucócito-endotélio, e os possíveis mecanismos intracelulares responsáveis pelos efeitos. A deficiência de GCen foi induzida em ratos Wistar machos, adultos por adrenalectomia bilateral. A participação de receptores de glicocorticoides (GC) foi avaliada em ratos normais tratados com o antagonista RU 38486. Animais falso-operados (FO), ou normais (N) foram empregados como controles. A deficiência hormonal foi constatada pela dosagem de corticosterona plasmática por radioimunoensaio e demonstraram valores significativamente baixos em animais adrenalectomizados (ADR). Ensaios de microscopia intravital mostraram que aumento exacerbado de leucócitos em comportamento \"rolling\" em vênulas pós-capilares de animais adrenalectomizados (ADR) não reflete alterações hemodinâmicas, uma vez que a deficiência hormonal não provocou modificações no diâmetro ou fluxo sangüíneo de vasos da microcirculação do músculo cremaster. No entanto, a determinação da expressão de moléculas de adesão em leucócitos circulantes por citometria de fluxo mostrou que neutrófilos de animais ADR apresentaram maior expressão de L-selectina que células de animais controles. Por outro lado, a expressão de L-selectina em granulócitos maduros presentes na medula óssea de animais ADR estava diminuída em comparação com células de animais controles. Este efeito pode estar envolvido com a maturação acelerada destas células na medula e com a neutrofilia detectada em animais ADR. É importante salientar que a estimulação de polimorfonucleares (PMN), coletados tanto do sangue como da medula, com fMLP mostrou que estas células estavam aptas a aumentar a expressão da molécula, indicando que as alterações nas suas expressões em animais ADR não são dependentes de modificações na capacidade de síntese. Adicionalmente, a ação dos GCen sobre a expressão de L-selectina parece não depender do GC, já que animais normais tratados com RU 38486 não apresentaram o mesmo padrão de alteração observada em animais ADR. Com o intuito de identificar os efeitos dos GCen sobre a capacidade individual de aderência do endotélio e do neutrófilo, ensaio de aderência in vitro foram realizados com cultura primária de célula endotelial (CE) obtida do músculo cremaster e com neutrófilos coletados da aorta abdominal. Os dados obtidos mostraram que menor número de PMN provenientes de animais ADR aderiram à CE de animal normal, mas por outro lado, a maior número de PMN de animais controles aderiram à CE de animais ADR. Em conjunto, estes dados indicam um controle diferente dos GCen sobre as células envolvidas no processo: facilitam a aderência de PMN e diminuem a aderência da CE. A investigação do papel dos GCen sobre a expressão de moléculas de adesão envolvidas no processo mostrou que os hormônios não interferem com a expressão basal de β2 integrina nos leucócitos, tanto nos circulantes quanto nos da medula. Adicionalmente, os dados de imunohistoquímica indicaram que os GCen modulam a expressão de moléculas responsáveis pela aderência. A expressão de ICAM-1 e PECAM-1 é significativamente maior no endotélio de vênulas de animais ADR que de animais controles. Associados, os dados aqui obtidos em animais ADR indicam um papel diferente dos CCen sobre a interação leucócito-endotélio. A modulação sobre a expressão de L-selectina pode estar envolvida na mobilização de neutrófilos para circulação e no comportamento rolling destas células. A subseqüente aderência dos leucócitos ao endotélio parece ser dependente de ações sobre a célula endotelial, através da modulação da expressão de moléculas da superfamília das imunoglobulinas.
The endogenous glucocorticoids (GCen) are important modulators of inflammatory reactions, acting in different aspects of the processes. In this context, it has been shown that GCen control leukocyte migration into focus of injuries, and one proposed mechanism of action is the modulation on leukocyte-endothelium interactions. Since adhesion molecules mediate cellular interactions, it has been evidenced that GCen control, direct or indirectly, the expression of these receptors on the cellular membranes during different stress conditions. However, data described in the literature are fragmentary and controversial. Then, the aim of this work was to investigate the role of the GCen on expressions of adhesion molecules involved in leukocyte-endothelium interactions and the possible intracellular mechanisms responsible for the effects. Adult male Wistar rats were submitted to bilateral adrenalectomy to induce adrenal hormone deficiency. The participation of glucocorticoid cytosolic receptor (GC) on the effects was evaluated in rats pre-treated with the glucocorticoid receptor antagonist RU 38 486. Sham-operated or normal rats were used as control. The hormone deficiency was assessed by quantification the plasmatic corticosterone by radioimmunoassay. Data showed marked lower values in adrenalectomized (ADR) than control rats. Intravital microscopy assays showed that the higher number of roller leukocytes in the postcapillary venules from cremaster muscle from ADR animals does not reflect hemodynamic alterations, given that hormonal deficiency did not modify the diameter or blood flow of microcirculation vessels. However, the determination of adhesion molecule expressions on circulating leukocytes by flow cytometry assay showed that neutrophils from ADR animals presented higher expression of L-selectin than cells from control animals. On the other hand, the expression of L-selectin on membranes of mature granulocytes in the bone marrow was decreased on cells from ADR rats. Together, these data suggest that modulation on L-selectin expression may be important target point of GE control and it may participate of the accelerated maturation of segmented cells in bone marrow, neutrophilia and in the elevated number of rolling leukocytes detected in ADR animals. It is important to emphasize that alterations on L-selectin expression on cells from ADR rats seem do not reflect an inability of its synthesis, since its expression after in vitro fMLP (formyl-Met-Leu-Phe) stimulation was not modified by hormonal deficiency. Additionally, the effect on L-selectin expression on circulating neutrophils may not be depend on the GC, since normal animal treated with RU 38486 presented expressions of L-selectin equivalent to those found in cells from control rats. To identify the effects of hormonal deficiency on individual ability of endothelium or neutrophils adherence, in vitro adherence assay was performed using both primary cultured endothelium from cremaster muscle and neutrophils collected from abdominal aorta. The results demonstrated that lesser number of PMN collected from ADR animals adhered to normal endothelium, while higher number of normal neutrophils adhered to endothelium from ADR rats. These latter results were corroborated by quantification of adhesion molecules expressions involved on adherence process by blood flow cytometer or by immunohistochemistry. The hormonal deficiency did not modify the β2 integrin expression on leukocytes, but enhanced the ICAM-1 and PECAM-1 expression on endothelium membrane of cremaster muscle venules from ADR animals. Together data obtained in ADR animals may indicate a different role of the GE on cells during the leukocyte-endothelium interaction. The modulation on L-selectin may be involved on neutrophil delivery into circulation and on the rolling of circulating neutrophils. The subsequent adherence of leukocytes to endothelium seems to be dependent on actions on endothelial cells, through modulation of expressions of immunoglobulins superfamily molecules.

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Liu, Li. « Complement and neutrophil activation on protein coated solid surfaces ». Göteborg : Dept. of General and Marine Microbiology and Dept of medical Microbiology and Immunology, University of Göteborg, 1997. http://catalog.hathitrust.org/api/volumes/oclc/38986844.html.

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Rigby, David Andrew. « Inflammation-induced migration of neutrophils across the lymphatic endothelium ». Thesis, University of Oxford, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.561107.

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The lymphatic system provides a conduit for the trafficking of immune cells from the periphery to draining lymph nodes, both for constitutive immune surveillance and during inflammation. Thus, leucocyte migration into the lymphatics represents an important step in the initiation of a primary immune response, which occurs within lymph nodes. Traditionally, it has been considered that neutrophils are absent from the afferent lymph, having a finite lifespan in the periphery after extravasation from the blood. However, recent research has reported the presence of neutrophils in lymph nodes, in animal models of infection, where neutrophil trafficking was found to occur through afferent lymphatic vessels. This thesis examines the mechanisms regulating neutrophil migration, both by the lymphatic endothelium and neutrophils themselves, under resting and inflammatory conditions. Primary human dermal lymphatic endothelial cells (HDLECs) respond to the pro- inflammatory cytokine, TNF-α by instigating a distinct expression programme, characterised by the up-regulation of various adhesion molecules (ICAM-1, VCAM-1, E-selectin), and CXC- chemokines (ENA-78, GROβ, IL-8), as well as other potential regulators of neutrophil entry such as constitutively expressed adhesion molecules, CD99 and ESAM. Moreover, neutrophils possess counter-receptors for these adhesion molecules and contain basement membrane-specific proteases (elastase) and matrix metalloproteinases (MMPs) such as MMPs -8 and -9, localised in intracellular granules, ready to be exocytosed upon inflammatory stimuli. In vitro data presented in this thesis demonstrate that neutrophil adhesion and transmigration of the lymphatic endothelium is entirely dependent on prior activation of the monolayer with TNF-a. Furthermore, the aforementioned lymphatic-expressed adhesion molecules and chemokines, as well as neutrophil-derived proteases and MMPs are shown to play critical roles in neutrophil adhesion and transmigration of the lymphatic endothelium. Subsequent in vivo experiments confirmed that neutrophil trafficking to lymph nodes across lymphatic vessels is wholly dependent on prior vaccination with Mycobacterium bovis Bacillus Calmette-Guerin (BCG) Tokyo-172. Moreover, neutrophils trafficking to lymph nodes across lymphatic vessels are shown to require ICAM-1. The results described in this thesis provide the first evidence that both the lymphatic endothelium and neutrophils act in concert to regulate entry to lymph nodes and determine the outcome of infection, or vaccination.

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Mitrophanous, Kyriacos Andreou. « Characterization of the murine formylated peptide chemotactic receptor ». Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243484.

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Thèses sur le sujet « Immunology, Neutrophil »

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