2,795 research outputs found

    Chicken BAFF

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    Members of the tumor necrosis factor (TNF) family play key roles in the regulation of inflammation, immune responses and tissue homeostasis. Here we describe the identification of the chicken homologue of mammalian B cell activating factor of the TNF family (BAFF/BLyS). By searching a chicken EST database we identified two overlapping cDNA clones that code for the entire open reading frame of chicken BAFF (chBAFF), which contains a predicted transmembrane domain and a putative furin protease cleavage site like its mammalian counterparts. The amino acid identity between soluble chicken and human BAFF is 76%, considerably higher than for most other known cytokines. The chBAFF gene is most strongly expressed in the bursa of Fabricius. Soluble recombinant chBAFF produced by human 293T cells interacted with the mammalian cell-surface receptors TACI, BCMA and BAFF-R. It bound to chicken B cells, but not to other lymphocytes, and it promoted the survival of splenic chicken B cells in culture. Furthermore, bacterially expressed chBAFF induced the selective expansion of B cells in the spleen and cecal tonsils when administered to young chicks. Our results suggest that like its mammalian counterpart, chBAFF plays an important role in survival and/or proliferation of chicken B cells

    Intermediary Organisations and the Hegemonisation of Social Entrepreneurship: Fantasmatic Articulations, Constitutive Quiescences, and Moments of Indeterminacy

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    The rapid rise of alternative organisations such as social enterprises is largely due to the promotional activities of intermediary organisations. So far, little is known about the affective nature of such activities. The present article thus investigates how intermediary organisations make social entrepreneurship palatable for a broader audience by establishing it as an object of desire. Drawing on affect-oriented extensions of Laclau and Mouffe's poststructuralist theory, hegemonisation is suggested as a way of understanding how social entrepreneurship is articulated through a complementary process of signification and affective investment. Specifically, by examining Austrian intermediaries, we show how social entrepreneurship is endowed with a sense of affective thrust that is based on three interlocking dynamics: the articulation of fantasies such as 'inclusive exclusiveness', 'large-scale social change' and 'pragmatic solutions'; the repression of anxiety-provoking and contentious issues (constitutive quiescences); as well as the use of conceptually vague, floating signifiers (moments of indeterminacy). Demonstrating that the hegemonisation of social entrepreneurship involves articulating certain issues whilst, at the same time, omitting others, or rendering them elusive, the article invites a counter-hegemonic critique of social entrepreneurship, and, on a more general level, of alternative forms of organising, that embraces affect as a driving force of change, while simultaneously affirming the impossibility of harmony and wholeness

    Touching Space: Distributed Ledger Technology for Tracking and Tracing Certificates

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    Components built into space vehicles and equipment (space products) must meet different regulatory requirements; in detail, each component must be certified and sustainably traceable at all times. Space engineers have expressed the need for an interoperable system to collect, manage and route certifications for components, parts and materials that go into space products. The lack of a unified approach in the European space industry is a challenge for companies involved in product development. This research proposes an open-source, secure, fast and distributed ledger technology (DLT) based solution that fits into any IT environment and is well adapted to the needs of manufacturing companies in the space sector. The results show that a blockchain-based solution based on 'Hyperledger Fabric' combined with the InterPlanetary File System is viable. The results can guide other researchers and practitioners to consider DLTs when changing their certification management paradigm with suppliers, customers and auditors

    Chicken BAFF—a highly conserved cytokine that mediates B cell survival

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    Members of the tumor necrosis factor (TNF) family play key roles in the regulation of inflammation, immune responses and tissue homeostasis. Here we describe the identification of the chicken homologue of mammalian B cell activating factor of the TNF family (BAFF/BLyS). By searching a chicken EST database we identified two overlapping cDNA clones that code for the entire open reading frame of chicken BAFF (chBAFF), which contains a predicted transmembrane domain and a putative furin protease cleavage site like its mammalian counterparts. The amino acid identity between soluble chicken and human BAFF is 76%, considerably higher than for most other known cytokines. The chBAFF gene is most strongly expressed in the bursa of Fabricius. Soluble recombinant chBAFF produced by human 293T cells interacted with the mammalian cell‐surface receptors TACI, BCMA and BAFF‐R. It bound to chicken B cells, but not to other lymphocytes, and it promoted the survival of splenic chicken B cells in culture. Furthermore, bacterially expressed chBAFF induced the selective expansion of B cells in the spleen and cecal tonsils when administered to young chicks. Our results suggest that like its mammalian counterpart, chBAFF plays an important role in survival and/or proliferation of chicken B cell

    Unique and conserved functions of B cell-activating factor of the TNF family (BAFF) in the chicken

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    The chicken represents the best-characterized animal model for B cell development in the so-called gut-associated lymphoid tissue (GALT) and the molecular processes leading to B cell receptor diversification in this species are well investigated. However, the mechanisms regulating B cell development and homeostasis in GALT species are largely unknown. Here we investigate the role played by the avian homologue of B cell-activating factor of the tumor necrosis factor family (BAFF). Flow cytometric analysis showed that the receptor for chicken B cell-activating factor of the tumor necrosis factor family (chBAFF) is expressed by mature and immature B cells. Unlike murine and human BAFF, chBAFF is primarily produced by B cells both in peripheral lymphoid organs and in the bursa of Fabricius, the chicken's unique primary lymphoid organ. In vitro and in vivo studies revealed that chBAFF is required for mature B cell survival. In addition, in vivo neutralization with a decoy receptor led to a reduction of the size and number of B cell follicles in the bursa, demonstrating that, in contrast to humans and mice, in chickens BAFF is also required for the development of immature B cells. Collectively, we show that chBAFF has phylogenetically conserved functions in mature B cell homeostasis but displays unique and thus far unknown properties in the regulation of B cell development in bird

    Discordant Increases in CD4+ T Cells in Human Immunodeficiency Virus-Infected Patients Experiencing Virologic Treatment Failure: Role of Changes in Thymic Output and T Cell Death

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    Some patients infected with human immunodeficiency virus (HIV) who are experiencing antiretroviral treatment failure have persistent improvement in CD4+ T cell counts despite high plasma viremia. To explore the mechanisms responsible for this phenomenon, 2 parameters influencing the dynamics of CD4+ T cells were evaluated: death of mature CD4+ T cells and replenishment of the CD4+ T cell pool by the thymus. The improvement in CD4+ T cells observed in patients with treatment failure was not correlated with spontaneous, Fas ligand-induced, or activation-induced T cell death. In contrast, a significant correlation between the improvement in CD4+ T cell counts and thymic output, as assessed by measurement of T cell receptor excision circles, was observed. These observations suggest that increased thymic output contributes to the dissociation between CD4+ T cell counts and viremia in patients failing antiretroviral therapy and support a model in which drug-resistant HIV strains may have reduced replication rates and pathogenicity in the thymu
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