1,930 research outputs found
Mitralklappenendokarditis nach tĂĽrkischem Opferfest
Zusammenfassung: Erysipelothrix rhusiopathiae ist der Erreger des Schweinerotlaufs. Systemische Infektionen durch E.rhusiopathiae sind eine Rarität, jedoch häufig (zu 90%) mit Endokarditiden verbunden. Ungefähr 60% der Endokarditiden entwickeln sich auf nicht vorgeschädigten Klappen, und trotz adäquater antibiotischer Therapie benötigen etwa ein Drittel der Patienten einen Klappenersatz. Wir beschreiben den Fall einer Hausfrau, die nach Zubereitung von Fleisch für das türkische Opferfest eine Mitralklappenendokarditis durch E.rhusiopathiae entwickelt
Multiple phenotypes conferred by a single insect symbiont are independent
Many microbial symbionts have multiple phenotypic consequences for their animal hosts. However, the ways in which different symbiont-mediated phenotypes combine to affect fitness are not well understood. We investigated whether there are correlations between different symbiont-mediated phenotypes. We used the symbiont Spiroplasma, a striking example of a bacterial symbiont conferring diverse phenotypes on insect hosts. We took 11 strains of Spiroplasma infecting pea aphids (Acyrthosiphon pisum) and assessed their ability to provide protection against the fungal pathogen Pandora neoaphidis and the parasitoids Aphidius ervi and Praon volucre. We also assessed effects on male offspring production for five of the Spiroplasma strains. All but one of the Spiroplasma strains provided very strong protection against the parasitoid P. volucre. As previously reported, variable protection against P. neoaphidis and A. ervi was also present; male-killing was likewise a variable phenotype. We find no evidence of any correlation, positive or negative, between the different phenotypes, nor was there any evidence of an effect of symbiont phylogeny on protective phenotype. We conclude that multiple symbiont-mediated phenotypes can evolve independently from one another without trade-offs between them
Fibrisoma limi gen. nov., sp. nov., an orange pigmented filamentous bacterium of the family Cytophagaceae isolated from North Sea tidal flats
An orange pigmented Gram-staining-negative, non motile, filament forming rod-shaped bacterium (BUZ 3T) was isolated from a coastal mud sample from the North Sea (Fedderwardersiel, Germany) and characterized taxonomically using a polyphasic approach. According to 16S rRNA gene sequence data it belongs the family Cytophagaceae, exhibiting low 16S rRNA gene sequence similarity (<90%) to members of the genera Spirosoma, Rudanella and Fibrella. The G+C content was 52.0 mol%. The major fatty acids were summed feature 3 (comprising C16:1{omega}7c and/or isoC15:0 2-OH), C16:1{omega}5c, and isoC17:0 3-OH. The major polar lipids consisted of phosphatidylethanolamine, and several aminolipids. On the basis of phenotypic, chemotaxonomic and phylogenetic data, it is proposed that, strain BUZ 3T represents a strain of a novel genus and species, for which the name Fibrisoma limi gen. nov., sp. nov. is proposed. The type strain is BUZ 3T (= DSMZ 22564T = CCUG 58137T
Short-term antigen presentation and single clonal burst limit the magnitude of the CD8(+) T cell responses to malaria liver stages.
Malaria sporozoites induce swift activation of antigen-specific CD8(+) T cells that inhibit the intracellular development of liver-stage parasites. The length of time of functional in vivo antigen presentation, estimated by monitoring the activation of antigen-specific CD8(+) T cells, is of short duration, with maximum T cell activation occurring within the first 8 h after immunization and lasting approximately 48 h. Although the magnitude of the CD8(+) T cell response closely correlates with the number of parasites used for immunization, increasing the time of antigen presentation by daily immunizations does not enhance the magnitude of this response. Thus, once a primary clonal burst is established, the CD8(+) T cell response becomes refractory or unresponsive to further antigenic stimulation. These findings strongly suggest that the most efficient strategy for the induction of primary CD8(+) T cell responses is the delivery of a maximal amount of antigen in a single dose, thereby ensuring a clonal burst that involves the largest number of precursors to become memory cells
Selected MicroRNAs Define Cell Fate Determination of Murine Central Memory CD8 T Cells
During an immune response T cells enter memory fate determination, a program that divides them into two main populations: effector memory and central memory T cells. Since in many systems protection appears to be preferentially mediated by T cells of the central memory it is important to understand when and how fate determination takes place. To date, cell intrinsic molecular events that determine their differentiation remains unclear. MicroRNAs are a class of small, evolutionarily conserved RNA molecules that negatively regulate gene expression, causing translational repression and/or messenger RNA degradation. Here, using an in vitro system where activated CD8 T cells driven by IL-2 or IL-15 become either effector memory or central memory cells, we assessed the role of microRNAs in memory T cell fate determination. We found that fate determination to central memory T cells is under the balancing effects of a discrete number of microRNAs including miR-150, miR-155 and the let-7 family. Based on miR-150 a new target, KChIP.1 (K + channel interacting protein 1), was uncovered, which is specifically upregulated in developing central memory CD8 T cells. Our studies indicate that cell fate determination such as surface phenotype and self-renewal may be decided at the pre-effector stage on the basis of the balancing effects of a discrete number of microRNAs. These results may have implications for the development of T cell vaccines and T cell-based adoptive therapies
An IFN-Îł-IL-18 Signaling Loop Accelerates Memory CD8+ T Cell Proliferation
Rapid proliferation is one of the important features of memory CD8+ T cells, ensuring rapid clearance of reinfection. Although several cytokines such as IL-15 and IL-7 regulate relatively slow homeostatic proliferation of memory T cells during the maintenance phase, it is unknown how memory T cells can proliferate more quickly than naïve T cells upon antigen stimulation. To examine antigen-specific CD8+ T cell proliferation in recall responses in vivo, we targeted a model antigen, ovalbumin(OVA), to DEC-205+ dendritic cells (DCs) with a CD40 maturation stimulus. This led to the induction of functional memory CD8+ T cells, which showed rapid proliferation and multiple cytokine production (IFN-γ, IL-2, TNF-α) during the secondary challenge to DC-targeted antigen. Upon antigen-presentation, IL-18, an IFN-γ-inducing factor, accumulated at the DC:T cell synapse. Surprisingly, IFN-γ receptors were required to augment IL-18 production from DCs. Mice genetically deficient for IL-18 or IFN-γ-receptor 1 also showed delayed expansion of memory CD8+ T cells in vivo. These results indicate that a positive regulatory loop involving IFN-γ and IL-18 signaling contributes to the accelerated memory CD8+ T cell proliferation during a recall response to antigen presented by DCs
Increased percentage of T cells with the expression of CD127 and CD132 in hypertrophic adenoid in children with otitis media with effusion
The hypertrophic adenoid may promote chronic suppurative otitis media in children as it fulfills its immune function. The number of lymphocytes in the adenoid and their cooperation in the immune response depend of on their proliferation and migration to the effector sites. Interleukin 7 (IL-7) is essential for the normal development and function lymphocytes. IL-7 plays pivotal role for activation and proliferation of T and B cells. The heterodimeric interleukin-7 receptor (IL-7R) is composed of the IL-7Rα (127) and the common cytokine receptor γc (CD132). The aim of this study was to evaluate the percentage of lymphocytes T (CD4+ and CD8+) with IL-7R (CD127 and CD132) expression in hypertrophic adenoid in children suffering with otitis media with effusion for a duration of 3 months. Adenoid excised due to hypertrophy with or without chronic otitis media with effusion was used as study material. CD4+ CD127+, CD4+132+, CD8+CD127+ and CD8+CD132+ cell subpopulations were identified using monoclonal antibodies and flow cytometry. The percentage of CD4+ and CD8+ T cells with CD127 receptor expression in hypertrophic adenoid of children with otitis media with effusion was statistically significantly higher than in hypertrophic adenoid group. The percentage of CD4+ T cells with CD132 expression in the study group was statistically significantly higher than in the reference group. The percentage of CD8+ T cells with CD132+ expression was not statistically different in both groups. The increased percentage of T lymphocytes with IL-7R expression (CD127 and CD132) in hypertrophic adenoid seems to influence the quantity of lymphocytes and upset the immunological function of tonsils which can influence the course of otitis media with effusion
Decay Kinetics of an Interferon Gamma Release Assay with Anti-Tuberculosis Therapy in Newly Diagnosed Tuberculosis Cases
Qualitative and quantitative changes in IGRA response offer promise as biomarkers to monitor Tuberculosis (TB) drug therapy, and for the comparison of new interventions. We studied the decay kinetics of TB-specific antigen T-cell responses measured with an in-house ELISPOT assay during the course of therapy.Newly diagnosed sputum smear positive TB cases with typical TB chest radiographs were recruited. All patients were given standard anti-TB treatment. Each subject was followed up for 6 months and treatment outcomes were documented. Blood samples were obtained for the ESAT-6 and CFP-10 (EC) ELISPOT at diagnosis, 1-, 2-, 4- and 6-months. Qualitative and quantitative reversion of the ELISPOT results were assessed with McNemar test, conditional logistic regression and mixed-effects hierarchical Poisson models.A total of 116 cases were recruited and EC ELISPOT was positive for 87% (95 of 109) at recruitment. There was a significant decrease in the proportion of EC ELISPOT positive cases over the treatment period (p<0.001). Most of the reversion occurred between the start and first month of treatment and at completion at 6 months. ESAT-6 had higher median counts compared to CFP-10 at all time points. Counts for each antigen declined significantly with therapy (p<0.001). Reverters had lower median SFUs at the start of treatment compared to non-Reverters for both antigens. Apart from the higher median counts for non-Reverters, no other risk factors for non-reversion were found.TB treatment induces qualitative and quantitative reversion of a positive in-house IGRA in newly diagnosed cases of active TB disease. As this does not occur reliably in the majority of cured individuals, qualitative and quantitative reversion of an IGRA ELISPOT has limited clinical utility as a surrogate marker of treatment efficacy
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