Browsing by Subject "Neutrophils"

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    An in vitro study of neutrophil chemotaxis
    (1976) Todd, Gail; Dowdle, E B
    When, at the beginning of 1972, my scientific attention was first drawn to the subject of cellular participation in the inflanunatory response, I was struck by the need for an understanding of the cellular and molecular mechanisms whereby blood leucocytes are attracted to an area of injury. The literature at that time contained good technical accounts of methods available for studying chemotaxis in vitro and many reports of diverse compounds of biological origin with attractant, or chemotactic, properties for motile, phagocytic cells. In general, these reports tended to substantiate the belief that chemical substances generated at an inflannnatory source attracted cells to that source in a teleologically appropriate way and they justified, by the consistent correlation observed, the relevance of in vitro procedures for studying the phenomenon. In other words, answers were available to the question "What substances attract?"; very few were available to the question, "How do they attract?".
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    The anti-Pseudomonas aeruginosa antibody Panobacumab is efficacious on acute pneumonia in neutropenic mice and has additive effects with meropenem
    (Public Library of Science, 2013) Secher, Thomas; Fas, Stefanie; Fauconnier, Louis; Mathieu, Marieke; Rutschi, Oliver; Ryffel, Bernhard; Rudolf, Michael
    Pseudomonas aeruginosa ( P. aeruginosa ) infections are associated with considerable morbidity and mortality in immunocompromised patients due to antibiotic resistance. Therefore, we investigated the efficacy of the anti- P. aeruginosa serotype O11 lipopolysaccharide monoclonal antibody Panobacumab in a clinically relevant murine model of neutropenia induced by cyclophosphamide and in combination with meropenem in susceptible and meropenem resistant P. aeruginosa induced pneumonia. We observed that P. aeruginosa induced pneumonia was dramatically increased in neutropenic mice compared to immunocompetent mice. First, Panobacumab significantly reduced lung inflammation and enhanced bacterial clearance from the lung of neutropenic host. Secondly, combination of Panobacumab and meropenem had an additive effect. Third, Panobacumab retained activity on a meropenem resistant P. aeruginosa strain. In conclusion, the present data established that Panobacumab contributes to the clearance of P. aeruginosa in neutropenic hosts as well as in combination with antibiotics in immunocompetent hosts. This suggests beneficial effects of co-treatment even in immunocompromised individuals, suffering most of the morbidity and mortality of P. aeruginosa infections.
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    BALB/c mice deficient in CD4 T cell IL-4Rα expression control Leishmania mexicana Load although female but not male mice develop a healer phenotype
    (Public Library of Science, 2011) Bryson, Karen J; Millington, Owain R; Mokgethi, Thabang; McGachy, H Adrienne; Brombacher, Frank; Alexander, James
    Immunologically intact BALB/c mice infected with Leishmania mexicana develop non-healing progressively growing lesions associated with a biased Th2 response while similarly infected IL-4Rα-deficient mice fail to develop lesions and develop a robust Th1 response. In order to determine the functional target(s) for IL-4/IL-13 inducing non-healing disease, the course of L. mexicana infection was monitored in mice lacking IL-4Rα expression in specific cellular compartments. A deficiency of IL-4Rα expression on macrophages/neutrophils (in LysMcreIL-4Rα−/lox animals) had minimal effect on the outcome of L. mexicana infection compared with control (IL-4Rα−/flox) mice. In contrast, CD4+ T cell specific (LckcreIL-4Rα−/lox) IL-4Rα−/− mice infected with L. mexicana developed small lesions, which subsequently healed in female mice, but persisted in adult male mice. While a strong Th1 response was manifest in both male and female CD4+ T cell specific IL-4Rα−/− mice infected with L. mexicana, induction of IL-4 was manifest in males but not females, independently of CD4+ T cell IL-4 responsiveness. Similar results were obtained using pan-T cell specific (iLckcreIL-4Rα−/lox) IL-4Rα−/− mice. Collectively these data demonstrate that upon infection with L. mexicana, initial lesion growth in BALB/c mice is dependent on non-T cell population(s) responsive to IL-4/IL-13 while progressive infection is dependent on CD4+ T cells responsive to IL-4.
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    Blood neutrophil counts in HIV-infected patients with pulmonary tuberculosis: association with sputum mycobacterial load
    (Public Library of Science, 2013) Kerkhoff, Andrew D; Wood, Robin; Lowe, David M; Vogt, Monica; Lawn, Stephen D
    BACKGROUND: Increasing evidence suggests that neutrophils play a role in the host response to Mycobacterium tuberculosis . We determined whether neutrophil counts in peripheral blood are associated with tuberculosis (TB) and with mycobacterial load in sputum in HIV-infected patients. METHODOLOGY/PRINCIPAL FINDINGS: Adults enrolling in an antiretroviral treatment (ART) clinic in a Cape Town township were screened for TB regardless of symptoms. Paired sputum samples were examined using liquid culture, fluorescence microscopy, and the Xpert MTB/RIF assay. Absolute neutrophil counts (ANC) were measured in blood samples. Of 602 HIV-infected patients screened, 523 produced one or more sputum samples and had complete results available for analysis. Among these 523 patients, the median CD4 count was 169×10 9 /L (IQR, 96-232) and median ANC was 2.6×10 9 /L (IQR, 1.9-3.6). Culture-positive pulmonary tuberculosis was diagnosed in 89 patients. Patients with TB had a median ANC of 3.4×10 9 /L (IQR, 2.4-5.1) compared to 2.5×10 9 /L (IQR, 1.8-3.4) among those who were culture negative (p<0.0001). In multivariable analyses, having pulmonary TB was associated with an adjusted risk ratio (aRR) of 2.6 (95%CI, 1.5-4.5) for having an ANC level that exceeded the median value (ANC ≥2.6×10 9 /L; p = 0.0006) and an aRR of 6.8 (95%CI, 2.3-20.4) for having neutrophilia defined by a neutrophil count exceeding the upper limit of the normal range (ANC >7.5×10 9 /L; p = 0.0005). Patients were then classified into four mutually exclusive groups with increasing sputum mycobacterial load as defined by the results of culture, Xpert MTB/RIF and sputum smear microscopy. Multivariable analyses demonstrated that increasing sputum mycobacterial load was positively associated with blood ANC ≥2.6×10 9 /L and with neutrophilia. Conclusions/Significance Increased blood neutrophil counts were independently associated with pulmonary TB and sputum mycobacterial burden in this HIV-infected patient group. This observation supports the growing body of literature regarding the potential role for neutrophils in the host response to TB.
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    IL-1 and IL-23 mediate early IL-17A production in pulmonary inflammation leading to late fibrosis
    (Public Library of Science, 2011) Gasse, Paméla; Riteau, Nicolas; Vacher, Rachel; Michel, Marie-Laure; Fautrel, Alain; di Padova, Franco; Fick, Lizette; Charron, Sabine; Lagente, Vincent; Eberl, Gérard
    BACKGROUND: Idiopathic pulmonary fibrosis is a devastating as yet untreatable disease. We demonstrated recently the predominant role of the NLRP3 inflammasome activation and IL-1β expression in the establishment of pulmonary inflammation and fibrosis in mice. METHODS: The contribution of IL-23 or IL-17 in pulmonary inflammation and fibrosis was assessed using the bleomycin model in deficient mice. RESULTS: We show that bleomycin or IL-1β-induced lung injury leads to increased expression of early IL-23p19, and IL-17A or IL-17F expression. Early IL-23p19 and IL-17A, but not IL-17F, and IL-17RA signaling are required for inflammatory response to BLM as shown with gene deficient mice or mice treated with neutralizing antibodies. Using FACS analysis, we show a very early IL-17A and IL-17F expression by RORγt + γδ T cells and to a lesser extent by CD4αβ + T cells, but not by iNKT cells, 24 hrs after BLM administration. Moreover, IL-23p19 and IL-17A expressions or IL-17RA signaling are necessary to pulmonary TGF-β1 production, collagen deposition and evolution to fibrosis. CONCLUSIONS: Our findings demonstrate the existence of an early IL-1β-IL-23-IL-17A axis leading to pulmonary inflammation and fibrosis and identify innate IL-23 and IL-17A as interesting drug targets for IL-1β driven lung pathology.
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    Immunomodulation with recombinant interferon-γ1b in pulmonary tuberculosis
    (Public Library of Science, 2009) Dawson, Rod; Condos, Rany; Tse, Doris; Huie, Maryann L; Ress, Stanley; Tseng, Chi-Hong; Brauns, Clint; Weiden, Michael; Hoshino, Yoshihiko; Bateman, Eric
    BACKGROUND: Current treatment regimens for pulmonary tuberculosis require at least 6 months of therapy. Immune adjuvant therapy with recombinant interferon-γ1b (rIFN-γb) may reduce pulmonary inflammation and reduce the period of infectivity by promoting earlier sputum clearance. METHODOLOGY/PRINCIPAL FINDINGS: We performed a randomized, controlled clinical trial of directly observed therapy (DOTS) versus DOTS supplemented with nebulized or subcutaneously administered rIFN-γ1b over 4 months to 89 patients with cavitary pulmonary tuberculosis. Bronchoalveolar lavage (BAL) and blood were sampled at 0 and 4 months. There was a significant decline in levels of inflammatory cytokines IL-1β, IL-6, IL-8, and IL-10 in 24-hour BAL supernatants only in the nebulized rIFN-γ1b group from baseline to week 16. Both rIFN-γ1b groups showed significant 3-fold increases in CD4+ lymphocyte response to PPD at 4 weeks. There was a significant (p = 0.03) difference in the rate of clearance of Mtb from the sputum smear at 4 weeks for the nebulized rIFN-γ1b adjuvant group compared to DOTS or DOTS with subcutaneous rIFN-γ1b. In addition, there was significant reduction in the prevalence of fever, wheeze, and night sweats at 4 weeks among patients receiving rFN-γ1b versus DOTS alone. CONCLUSION: Recombinant interferon-γ1b adjuvant therapy plus DOTS in cavitary pulmonary tuberculosis can reduce inflammatory cytokines at the site of disease, improve clearance of Mtb from the sputum, and improve constitutional symptoms. Trial Registration ClinicalTrials.gov NCT00201123
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    Improving Reconstituted HDL Composition for Efficient Post-Ischemic Reduction of Ischemia Reperfusion Injury
    (Public Library of Science, 2015) Brulhart-Meynet, Marie-Claude; Braunersreuther, Vincent; Brinck, Jonas; Montecucco, Fabrizio; Prost, Jean-Christophe; Thomas, Aurelien; Galan, Katia; Pelli, Graziano; Pedretti, Sarah; Vuilleumier, Nicolas
    BACKGROUND: New evidence shows that high density lipoproteins (HDL) have protective effects beyond their role in reverse cholesterol transport. Reconstituted HDL (rHDL) offer an attractive means of clinically exploiting these novel effects including cardioprotection against ischemia reperfusion injury (IRI). However, basic rHDL composition is limited to apolipoprotein AI (apoAI) and phospholipids; addition of bioactive compound may enhance its beneficial effects. Objective The aim of this study was to investigate the role of rHDL in post-ischemic model, and to analyze the potential impact of sphingosine-1-phosphate (S1P) in rHDL formulations. Methods and RESULTS: The impact of HDL on IRI was investigated using complementary in vivo , ex vivo and in vitro IRI models. Acute post-ischemic treatment with native HDL significantly reduced infarct size and cell death in the ex vivo , isolated heart (Langendorff) model and the in vivo model (-48%, p<0.01). Treatment with rHDL of basic formulation (apoAI + phospholipids) had a non-significant impact on cell death in vitro and on the infarct size ex vivo and in vivo . In contrast, rHDL containing S1P had a highly significant, protective influence ex vivo , and in vivo (-50%, p<0.01). This impact was comparable with the effects observed with native HDL. Pro-survival signaling proteins, Akt, STAT3 and ERK1/2 were similarly activated by HDL and rHDL containing S1P both in vitro (isolated cardiomyocytes) and in vivo . CONCLUSION: HDL afford protection against IRI in a clinically relevant model (post-ischemia). rHDL is significantly protective if supplemented with S1P. The protective impact of HDL appears to target directly the cardiomyocyte.
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    Microbial ligand costimulation drives neutrophilic steroid-refractory asthma
    (Public Library of Science, 2015) Hadebe, Sabelo; Kirstein, Frank; Fierens, Kaat; Chen, Kong; Drummond, Rebecca A; Vautier, Simon; Sajaniemi, Sara; Murray, Graeme; Williams, David L; Redelinghuys, Pierre; Reinhart, Todd A; Junecko, Beth A Fallert; Kolls, Jay K; Lambrecht, Bart N; Brombacher, Frank; Brown, Gordon D
    Asthma is a heterogeneous disease whose etiology is poorly understood but is likely to involve innate responses to inhaled microbial components that are found in allergens. The influence of these components on pulmonary inflammation has been largely studied in the context of individual agonists, despite knowledge that they can have synergistic effects when used in combination. Here we have explored the effects of LPS and β-glucan, two commonly-encountered microbial agonists, on the pathogenesis of allergic and non-allergic respiratory responses to house dust mite allergen. Notably, sensitization with these microbial components in combination acted synergistically to promote robust neutrophilic inflammation, which involved both Dectin-1 and TLR-4. This pulmonary neutrophilic inflammation was corticosteroid-refractory, resembling that found in patients with severe asthma. Thus our results provide key new insights into how microbial components influence the development of respiratory pathology.
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    Myeloid derived suppressor cells are present at high frequency in neonates and suppress in vitro T cell responses
    (Public Library of Science, 2014) Gervassi, Ana; Lejarcegui, Nicholas; Dross, Sandra; Jacobson, Amanda; Itaya, Grace; Kidzeru, Elvis; Gantt, Soren; Jaspan, Heather; Horton, Helen
    Over 4 million infants die each year from infections, many of which are vaccine-preventable. Young infants respond relatively poorly to many infections and vaccines, but the basis of reduced immunity in infants is ill defined. We sought to investigate whether myeloid-derived suppressor cells (MDSC) represent one potential impediment to protective immunity in early life, which may help inform strategies for effective vaccination prior to pathogen exposure. We enrolled healthy neonates and children in the first 2 years of life along with healthy adult controls to examine the frequency and function of MDSC, a cell population able to potently suppress T cell responses. We found that MDSC, which are rarely seen in healthy adults, are present in high numbers in neonates and their frequency rapidly decreases during the first months of life. We determined that these neonatal MDSC are of granulocytic origin (G-MDSC), and suppress both CD4+ and CD8+ T cell proliferative responses in a contact-dependent manner and gamma interferon production. Understanding the role G-MDSC play in infant immunity could improve vaccine responsiveness in newborns and reduce mortality due to early-life infections.
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    A neutral protease of the neutrophil surface : role in the proteolysis of C-reactive protein and fibrinogen
    (1995) Kelly, Sharon Lesley; Shephard, Enid
    Both of the acute phase reactants, C-reactive protein and fibrinogen, as well as neutrophils have been shown to accumulate at sites of tissue injury or inflammation. The association of C-reactive protein with neutrophils and the concomitant degradation of this ligand by a phorbol 12-myristate 13 acetateactivatable membrane-associated neutral protease has been shown in previous studies. Degradation of C-reactive protein by the neutrophil protease was shown to result in peptides with an ability to modulate various immune functions of the neutrophil. The aim of this study has been to investigate specific characteristics of the protease, with respect to cellular distribution and molecular size. The ability of this neutrophil membrane-associated protease to degrade the acute phase protein, fibrinogen was investigated. The mechanism of degradation of both C-reactive protein and fibrinogen during their association with the neutrophil was also examined. The neutrophil protease, capable of degrading C-reactive protein, was also associated with the cytoskeleton and was proposed to be a submembrane protease localised at sites of attachment of the membrane with the cytoskeleton. The protease was found to have a molecular mass of approximately 600 kDa which, on sodium dodecyl sulphate polyacrylamide gel electrophoresis, separated into four bands which migrated to molecular mass values of 209 kDa, 316 kDa, 398 kDa and 501 kDa. This protease also possessed fibrinogenolytic activity. The fibrinogen degradation products generated by this neutrophil membrane-associated protease were distinct from the products generated by the fibrinogenolytic systems of plasmin, human neutrophil elastase and neutrophil lysosomal enzymes and were unclottable through cleavage of the Aα chain from the N-terminus and the Bβ and γ chains from the C-terminus. N-terminal cleavage of the Aα chain by the neutrophil membrane-associated protease generated the Aα1-21 peptide, previously regarded as a unique consequence of elastase activity. Degradation of C-reactive protein and fibrinogen occurred as a result of their interaction with the neutrophil near to the CD11c integrin receptor. This interaction resulted in the egress of proteolytic activity into the extracellular medium. The fibrinogen products generated outside the cell associated with the neutrophil via the β₂ integrin receptors and the IgG Fc receptor. The interaction of the Creactive protein degradation products with the neutrophil could not be determined. Both C-reactive protein and fibrinogen are degraded by non-stimulated neutrophils but activation with phorbol 12- myristate 13 acetate resulted in maximum degradation This upregulation of activity was achieved through activation of H7 and trifluoperazine inhibitable cellular kinases and changes in microfilament assembly. The generation of non-clottable fibrinogen together with possible modulation of neutrophil receptormediated functions by the fibringen degradation products as well as the knowledge that the neutrophil protease generates C-reactive protein peptides with immunomodulatory activity implicates this neutrophil membrane-associated protease in the modulation of various inflammatory processes.