902 resultados para T-Lymphocytes, Regulatory -- immunology
Resumo:
Nutrition is critical to immune defence and parasite resistance, which not only affects individual organisms, but also has profound ecological and evolutionary consequences. Nutrition and immunity are complex traits that interact via multiple direct and indirect pathways, including the direct effects of nutrition on host immunity but also indirect effects mediated by the host's microbiota and pathogen populations. The challenge remains, however, to capture the complexity of the network of interactions that defines nutritional immunology. The aim of this paper is to discuss the recent findings in nutritional research in the context of immunological studies. By taking examples from the entomological literature, we argue that insects provide a powerful tool for examining the network of interactions between nutrition and immunity due to their tractability, short lifespan and ethical considerations. We describe the relationships between dietary composition, immunity, disease and microbiota in insects, and highlight the importance of adopting an integrative and multi-dimensional approach to nutritional immunology.
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Mechanisms of antibiotic resistance were examined in nalidixic acid-resistant Salmonella enterica serovar Enteritidis field isolates displaying decreased susceptibility to ciprofloxacin and in in vitro-derived ciprofloxacin-resistant mutants (104-cip and 5408-cip). All field isolates harbored a single gyrA mutation (D87Y). Deletion of acrB and complementation with wild-type gyrA increased quinolone susceptibility. Selection for ciprofloxacin resistance was associated with the development of an additional gyrA (S83F) mutation in 104-cip, novel gyrB (E466D) and parE (V461G) mutations in 5408-cip, overexpression of acrB and decreased susceptibility to nonquinolone antibiotics in both mutants, and decreased OmpF production and altered lipopoly- saccharide in 104-cip. Complementation of mutated gyrA and gyrB with wild-type alleles restored susceptibility to quinolones in 104-cip and significantly decreased the ciprofloxacin MIC in 5408-cip. Complementation of parE had no effect on quinolone MICs. Deletion of acrB restored susceptibility to ciprofloxacin and other antibiotics tested. Both soxS and marA were overexpressed in 104-cip, and ramA was overexpressed in 5408-cip. Inactivation of each of these global regulators lowered ciprofloxacin MICs, decreased expression of acrB, and restored susceptibility to other antibiotics. Mutations were found in soxR (R20H) and in soxS (E52K) in 104-cip and in ramR (G25A) in 5408-cip. In conclusion, both efflux activity and a single gyrA mutation contribute to nalidixic acid resistance and reduced ciprofloxacin sensitivity. Ciprofloxacin resistance and decreased susceptibility to multiple antibiotics can result from different genetic events leading to development of target gene mutations, increased efflux activity resulting from differential expression of global regulators associated with mutations in their regulatory genes, and possible altered membrane permeability.
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The inference of gene regulatory networks gained within recent years a considerable interest in the biology and biomedical community. The purpose of this paper is to investigate the influence that environmental conditions can exhibit on the inference performance of network inference algorithms. Specifically, we study five network inference methods, Aracne, BC3NET, CLR, C3NET and MRNET, and compare the results for three different conditions: (I) observational gene expression data: normal environmental condition, (II) interventional gene expression data: growth in rich media, (III) interventional gene expression data: normal environmental condition interrupted by a positive spike-in stimulation. Overall, we find that different statistical inference methods lead to comparable, but condition-specific results. Further, our results suggest that non-steady-state data enhance the inferability of regulatory networks.
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F. hepatica infections were established in rats and immune responses were monitored during primary and challenge infections. Antibody levels peaked at 3 weeks post-primary infection and at 6 days post-challenge infection. No significant correlation was found between antibody titre and number of flukes recovered at autopsy. Immunoblotting revealed a limited number of immunogenic polypeptides. When antibodies from these reactive bands were eluted and tested by IFA they all gave identical binding patterns: on juvenile fluke sections tegumental syncytium, tegumental cells and gut cells were labelled, while on adult sections the same antibodies labelled gut cells, reproductive tissue, excretory ducts and flame cells. This suggested that these tissues shared a common epitope or range of epitopes. A pronounced eosinophilia was observed throughout the infection period studied and infected liver sections showed massive cellular infiltration. Histochemical and immunocytochemical investigation of infected liver revealed the presence of large numbers of eosinophils, neutrophils, lymphocytes and phagocytes. The implications of these findings, to an understanding of concomitant immunity in the rat are discussed.
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The joint fluids of 37 patients with rheumatoid arthritis, eight patients with traumatic injuries to their joints, two patients with Reiter's syndrome and three patients with psoriatic arthritis were tested for the presence of B cell colony stimulating activity (B cell CSA). B cell CSA was found in all of the joint fluids from the patients with rheumatoid arthritis but in none of the joint fluids from patients with traumatic injuries to their joints or in the joint fluids from the patients with Reiter's syndrome. A trace of B cell CSA was found in the joint fluid of one of the three patients with psoriatic arthritis. There was a positive correlation (r = 0.796) between the amount of rheumatoid factor present in the joint fluids and the titre of B cell CSA. This correlation was highly significant (P less than 0.001). The B cell CSA was localized to component(s) with molecular weight ranges 115-129 kD and 64-72 kD and an isoelectric point of 6.8. Its activity was sensitive to reduction with 2-mercaptoethanol and to the oxidising action of potassium periodate.
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We describe a simple one-step technique for the growth of human B cell colonies in semi-solid agar in vitro. This method used conditioned medium from the human plasmacytoma cell line LICR-LON-H My 2 as a source of stimulating activity. A linear relationship exists between the number of B cells seeded and the number of colonies formed (r = 0.95). Most colony forming cells, approximately 1 in 500 of B cells seeded, lack surface immunoglobulin, possess Fc receptors and mark with the Leu 12 monoclonal antibody. Cells within developing colonies are found to have cytoplasmic IgM, IgA and IgG depending on the length of time in culture.
Resumo:
We have characterized the pre-B cell colony stimulating activity (pre-B cell CSA) from LICR LON HMY2 conditioned medium (CM) by a variety of biochemical techniques. Pre-B cell CSA was found to be associated with a heat stable glycoprotein which has an isoelectric point of 8.3 and a mol. wt, as determined by polyacrylamide gel electrophoresis, of 28-32 kD. The relationship of this activity to previously described factors acting on cells of the B cell lineage is discussed.
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The departure point for the paper is the need to scrutinise previously unconsidered dimensions which are fundamental to understanding the dynamics of the planning enforcement system. Drawing upon emerging themes in regulation theory the paper fuses these with knowledge constructs. The rationale is that regulatory regimes must be informed by knowledge imparted from a range of sources and the resultant quality of decision making is inextricably linked to the robustness and completeness of the evidence base collated.
The theoretical analysis, coupled with proposed radical legislative changes, provides a lens for an empirical investigation which scrutinises tactics, strategies, operational mechanisms, attitudinal dimensions and ethics with a view to identifying key factors impacting upon enforcement efficacy. Prizes and pitfalls are identified in the course of the analysis and evaluation, with evidence-based remedies suggested where appropriate. The paper concludes by reflecting on the importance of theoretical synergy, epistemological advancement, taking cognisance of ethical and attitudinal challenges facing the planning profession; and, stresses the importance of identifying and bringing to book those who flagrantly breach the Code of Professional Conduct.
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As devolution expands across the UK, Northern Ireland (NI) is witnessing the development of new architecture to devolve planning powers. With serious criticism targeted at the legislative provisions for enforcement, this investigation endeavours to assess the robustness of the planning framework through a synergy of theory, law and practice. The paper demonstrates the value of theory in not only supplying a lens that allows both legislative frameworks and praxis to be deconstructed, but also in enabling the identification and scrutiny of underlying problems that pervade the system.
Resumo:
BACKGROUND: Experimental autoimmune encephalomyelitis (EAE) is an animal model of autoimmune inflammatory demyelination that is mediated by Th1 and Th17 cells. The transcription factor interferon regulatory factor 3 (IRF3) is activated by pathogen recognition receptors and induces interferon-beta production.
METHODS: To determine the role of IRF3 in autoimmune inflammation, we immunised wild-type (WT) and irf3-/- mice to induce EAE. Splenocytes from WT and irf3-/- mice were also activated in vitro in Th17-polarising conditions.
RESULTS: Clinical signs of disease were significantly lower in mice lacking IRF3, with reduced Th1 and Th17 cells in the central nervous system. Peripheral T-cell responses were also diminished, including impaired proliferation and Th17 development in irf3-/- mice. Myelin-reactive CD4+ cells lacking IRF3 completely failed to transfer EAE in Th17-polarised models as did WT cells transferred into irf3-/- recipients. Furthermore, IRF3 deficiency in non-CD4+ cells conferred impairment of Th17 development in antigen-activated cultures.
CONCLUSION: These data show that IRF3 plays a crucial role in development of Th17 responses and EAE and warrants investigation in human multiple sclerosis.
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In the aftermath of the financial crash of 2008, policy makers operating in international financial regulatory networks discovered macroprudential regulation (MPR), but macroprudential regulation has had a stunted or arrested development that can be explained with reference to five factors that are recounted in this article
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Developed countries, led by the EU and the US, have consistently called for ‘deeper integration’ over the course of the past three decades i.e., the convergence of ‘behind-the-border’ or domestic polices and rules such as services, competition, public procurement, intellectual property (“IP”) and so forth. Following the collapse of the Doha Development Round, the EU and the US have pursued this push for deeper integration by entering into deep and comprehensive free trade agreements (“DCFTAs”) that are comprehensive insofar as they are not limited to tariffs but extend to regulatory trade barriers. More recently, the EU and the US launched negotiations on a Transatlantic Trade and Investment Partnership (“TTIP”) and a Trade in Services Agreement (“TISA”), which put tackling barriers resulting from divergences in domestic regulation in the area of services at the very top of the agenda. Should these agreements come to pass, they may well set the template for the rules of international trade and define the core features of domestic services market regulation. This article examines the regulatory disciplines in the area of services included in existing EU and US DCFTAs from a comparative perspective in order to delineate possible similarities and divergences and assess the extent to which these DCFTAs can shed some light into the possible outcome and limitations of future trade negotiations in services. It also discusses the potential impact of such negotiations on developing countries and, more generally, on the multilateral process.
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This article discusses whether European social partners can derive the competence to autonomously devise European collective labour agreements from Article 139 EC (equals Article III-212 Constitution of Europe). Placing the question in the context of discussions of EU governance and private lawmaking in general, the author starts with a comparative overview of legal conceptions for collective labour agreements in Europe, focusing on three Member States' orders where their effects are not or only partly regulated by state legislation. Based on this comparison, she analyses Article 139(2) and offers a new interpretation of its provisions concerning autonomous implementation of European social partner agreements. She concludes that European social partners do have the competence to agree on a basic agreement stating the rules for European collective bargaining autonomously.