Browsing by Subject "Immunity"

Now showing 1 - 5 of 5
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    Differences in genotype and virulence among four multidrug-resistant Streptococcus pneumoniae isolates belonging to the PMEN1 clone
    (Public Library of Science, 2011) Hiller, N Luisa; Eutsey, Rory A; Powell, Evan; Earl, Joshua P; Janto, Benjamin; Martin, Darren P; Dawid, Suzanne; Ahmed, Azad; Longwell, Mark J; Dahlgren, Margaret E
    We report on the comparative genomics and characterization of the virulence phenotypes of four S. pneumoniae strains that belong to the multidrug resistant clone PMEN1 (Spain 23F ST81). Strains SV35-T23 and SV36-T3 were recovered in 1996 from the nasopharynx of patients at an AIDS hospice in New York. Strain SV36-T3 expressed capsule type 3 which is unusual for this clone and represents the product of an in vivo capsular switch event. A third PMEN1 isolate - PN4595-T23 - was recovered in 1996 from the nasopharynx of a child attending day care in Portugal, and a fourth strain - ATCC700669 - was originally isolated from a patient with pneumococcal disease in Spain in 1984. We compared the genomes among four PMEN1 strains and 47 previously sequenced pneumococcal isolates for gene possession differences and allelic variations within core genes. In contrast to the 47 strains - representing a variety of clonal types - the four PMEN1 strains grouped closely together, demonstrating high genomic conservation within this lineage relative to the rest of the species. In the four PMEN1 strains allelic and gene possession differences were clustered into 18 genomic regions including the capsule, the blp bacteriocins, erythromycin resistance, the MM1-2008 prophage and multiple cell wall anchored proteins. In spite of their genomic similarity, the high resolution chinchilla model was able to detect variations in virulence properties of the PMEN1 strains highlighting how small genic or allelic variation can lead to significant changes in pathogenicity and making this set of strains ideal for the identification of novel virulence determinants.
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    Interleukin 4 promotes the development of ex-Foxp3 Th2 cells during immunity to intestinal helminths
    (2017) Pelly, Victoria S; Gialitakis, Manolis; Okoye, Isobel S; RYckerl, Dominik; Allen, Judith E; Brombacher, Frank; Wilson, Mark S
    Immunity to intestinal helminth infections requires the rapid activation of T helper 2 cells (Th2 cells). However, simultaneous expansion of CD4 + Foxp3 + regulatory T cells (T reg cells) impedes protective responses, resulting in chronic infections. The ratio between T reg and effector T cells can therefore determine the outcome of infection. The redifferentiation of T reg cells into Th cells has been identified in hyperinflammatory diseases. In this study, we asked whether ex–T reg Th2 cells develop and contribute to type-2 immunity. Using multigene reporter and fate-reporter systems, we demonstrate that a significant proportion of Th2 cells derive from Foxp3 + cells after Heligmosomoides polygyrus infection and airway allergy. Ex-Foxp3 Th2 cells exhibit characteristic Th2 effector functions and provide immunity to H. polygyrus . Through selective deletion of Il4ra on Foxp3 + cells, we further demonstrate IL-4 is required for the development of ex-Foxp3 Th2 cells. Collectively, our findings indicate that converting T reg cells into Th2 cells could concomitantly enhance Th2 cells and limit T reg cell–mediated suppression.
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    Measles vaccination coverage in high-incidence areas of the Western Cape, following the mass vaccination campaign
    (2013) Bernhardt, G L; Cameron, N A; Willems, B; Boulle, A; Coetzee, D
    BACKGROUND: Despite significant advances in measles control, large epidemics occurred in many African countries in 2009 - 2011, including South Africa. South Africa's control strategy includes mass vaccination campaigns about every 4 years, the last of which was conducted nationally in April 2010 and coincided with the epidemic. AIM: A community survey was conducted in the Western Cape to assess measles vaccination coverage attained by routine and campaign services, in children aged 6 months to 59 months at the time of the mass campaign, from high-incidence areas. METHODS: Households were consecutively sampled in high-incidence areas identified using measles epidemic surveillance data. A caregiver history of campaign vaccination and routine vaccination status from the child's Road to Health card were collected. Pre- and post-campaign immunity was estimated by analytical methods. RESULTS: Of 8 332 households visited, there was no response at 3 435 (41.2%); 95.1% (1 711/1 800) of eligible households participated; and 91.2% (1 448/1 587; 95% confidence interval 86 - 94%) of children received a campaign vaccination. Before the campaign, 33.0% (103/312) of 9 - 17-month-olds had not received a measles vaccination, and this was reduced to 4.5% (14/312) after the campaign. Of the 1 587 children, 61.5% were estimated to have measles immunity before the campaign, and this increased to 94.0% after the campaign. DISCUSSION: Routine services had failed to achieve adequate herd immunity in areas with suspected highly mobile populations. Mass campaigns in such areas in the Western Cape significantly increased coverage. Extra vigilance is required to monitor and sustain adequate coverage in these areas.
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    Seminal Fluid-Mediated Inflammation in Physiology and Pathology of the Female Reproductive Tract
    (2016) Adefuye, Anthonio O; Adeola, Henry A; Sales, Kurt J; Katz, Arieh A
    Inflammation is a multifaceted process involving a host of resident and recruited immune cells that eliminate the insult or injury and initiate tissue repair. In the female reproductive tract (FMRT), inflammation-mediated alterations in epithelial, vascular, and immune functions are important components of complex physiological processes and many local and systemic pathologies. It is well established that intracoital and postcoital function of seminal fluid (SF) goes beyond nutritive support for the spermatozoa cells. SF, in particular, the inflammatory bioactive lipids, and prostaglandins present in vast quantities in SF, have a role in localized immune modulation and regulation of pathways that can exacerbate inflammation in the FMRT. In sexually active women SF-mediated inflammation has been implicated in physiologic processes such as ovulation, implantation, and parturition while also enhancing tumorigenesis and susceptibility to infection. This review highlights the molecular mechanism by which SF regulates inflammatory pathways in the FMRT and how alterations in these pathways contribute to physiology and pathology of the female reproductive function. In addition, based on findings from TaqMan® 96-Well Plate Arrays, on neoplastic cervical cells treated with SF, we discuss new findings on the role of SF as a potent driver of inflammatory and tumorigenic pathways in the cervix.
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    Surfactant Protein-D is essential for immunity to Helminth Infection
    (Public Library of Science, 2016) Thawer, Sumaiyya; Auret, Jennifer; Schnoeller, Corinna; Chetty, Alisha; Smith, Katherine; Darby, Matthew; Roberts, Luke; Mackay, Rosie-Marie; Whitwell, Harry J; Timms, John F; Madsen, Jens; Selkirk, Murray E; Brombacher, Frank; Clark, Howard William; Horsnell, William G C
    Author Summary Infections by parasitic worms are very common, and controlling them is a major medical and veterinary challenge. Very few drugs exist to treat them, and the parasites can develop resistance to these. In order to find new ways to control worm infections, understanding how our immune system responds to them is essential. Many important parasitic worm infections move through the host lung. In this study we show that a major secreted protein in the lung, Surfactant Protein D (SP-D), is essential for immunity to a parasitic worm infection. We found that this protein binds to worm larvae in the lung to help the immune system kill them. Infecting mice that do not express SP-D with worms demonstrates SP-D is important in this immune response. These mice are unable to launch an effective anti-worm immune response and have many more worms in their intestine compared to mice that do express SP-D. We also show that if we increase SP-D levels in the lung the mouse has better immunity to worms. Together this shows for the first time that SP-D is very important for immunity to worm infections.