947 resultados para Antibody decay
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Breeder feed restriction may negatively affect broiler progeny immunity. Sources of trace minerals (TM) with higher bioavailability in breeder diets have been reported to enhance humoral and cellular immunity in broiler progeny. An experiment was conducted to examine the effects of breeder feeding programs and TM dietary sources on maternal antibody transfer and humoral immune response of progeny to a live vaccine against Newcastle disease virus (NDV). Cobb 500 breeders were fed according to 2 feed allocation programs, sigmoid late fast and sigmoid late slow, from 14 to 29 wk of age. From 56 to 62 wk of age, breeders were fed with either inorganic TM or an organic source (OTM) to replace 30% of Cu, Zn, and Mn. Progeny broilers were vaccinated intraocularly with La Sota NDV vaccine at 7 d of age. Blood samples were collected at hatching, 4, and 14 d postvaccination. Serum antibody levels against NDV were assessed by ELISA and cytokine expression by real time PCR. At hatching, late slow breeder progeny fed diets with 30% OTM had higher antibody titers as compared with progeny of breeders fed 100% inorganic TM. Similar results were observed 2 wk postvaccination. Breeder feeding programs and TM sources affected the expression level of IL-4 in NDV vaccinated broiler progeny. It was concluded that breeder feeding programs influenced humoral immune response to NDV vaccine in the broiler progeny, and 30% OTM may increase these responses. © 2013 Poultry Science Association, Inc.
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Because an enriched environment (EE) enhances T-cell activity and T-lymphocytes contribute to immunopathogenesis during heterologous dengue virus (DENV) infections, we hypothesised that an EE increases dengue severity. To compare single serotype (SS) and antibody-enhanced disease (AED) infections regimens, serial intraperitoneal were performed with DENV3 (genotype III) infected brain homogenate or anti-DENV2 hyperimmune serum followed 24 h later by DENV3 (genotype III) infected brain homogenate. Compared AED for which significant differences were detected between the EE and impoverished environmental (IE) groups (Kaplan-Meyer log-rank test, p = 0.0025), no significant differences were detected between the SS experimental groups (Kaplan-Meyer log-rank test, p = 0.089). Survival curves from EE and IE animals infected with the AED regimen were extended after corticoid injection and this effect was greater in the EE than in the IE group (Kaplan-Meyer log-rank test, p = 0.0162). Under the AED regimen the EE group showed more intense clinical signs than the IE group. Dyspnoea, tremor, hunched posture, ruffled fur, immobility, pre-terminal paralysis, shock and death were associated with dominant T-lymphocytic hyperplasia and presence of viral antigens in the liver and lungs. We propose that the increased expansion of these memory T-cells and serotype cross-reactive antibodies facilitates the infection of these cells by DENV and that these events correlate with disease severity in an EE.
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Prevalence of human T cell leukemia virus-I (HTLV-I) antibody among populations living in the Amazon region of Brazil (preliminary report)NakauchiC. M.LinharesA. C.MaruyamaK.KanzakiL. I.MacedoJ. E.AzevedoV. N.CassebJ. S. R. Fundação Serviços de Saúde Pública, Seção de Vírus, Instituto Evandro Chagas Belém Brasil Chiba Cancer Research Institute, Department of Pathology Chiba Japan Universidade Federal do Pará Belém Brasil Instituto Offir Loyola Belém Brasil Faculdade Estadual de Medicina Belém Brasil 0319908512933Forty-tree (31.4%) out of 137 serum samples obtained from two Indian communities living in the Amazon region were found to be positive for HTLV-I antibody, as tested by enzyme-linked immunosorbent assay (Elisa). Eighty-two sera were collected from Mekranoiti Indians, yielding 39% of positivity, whereas 11 (20.0%) or the 55 Tiriyo serum samples had antibody to HTLV-I. In addition, positive results occurred in 10 (23.2%) out of 43 sera obtained from patients living in the Belem area, who were suffering from cancer affecting different organs. Five (16.7%) out of 30 Elisa positive specimens were also shown to be positive by either Western blot analysis (WB) or indirect immunogold electron microscopy (IIG-EM).
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Soroprevalências para HTLV-I de 3,63% (02/55), 12,9% (10/82) e 13,88% (10/72) foram demonstradas entre os Tiryió, Mekranoiti e Xicrin, respectivamente - indígenas habitantes da Amazônia -, utilizando-se a técnica de "Western Blot" (WBEI). Por outro lado, a imunomicroscopia eletrônica indireta (IIME) revelou como positivos 2 Tiryió, 9 Mekranoiti e 6 Xicrins. Das 44 amostras de soro oriundas de migrantes japoneses, nenhuma resultou positiva pelas duas técnicas antes mencionadas. Foram reativos por ambos os métodos, 1, 8 e 6 amostras dos índios Tiryió, Mekranoiti e Xicrin, respectivamente. Nossos resultados representam uma forte evidência de que o HTV-I e/ou variante(s) antigenicamente similar(es) circula(m) entre populações que habitam a região amazônica do Brasil.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Our understanding of how anthropogenic habitat change shapes species interactions is in its infancy. This is in large part because analytical approaches such as network theory have only recently been applied to characterize complex community dynamics. Network models are a powerful tool for quantifying how ecological interactions are affected by habitat modification because they provide metrics that quantify community structure and function. Here, we examine how large-scale habitat alteration has affected ecological interactions among mixed-species flocking birds in Amazonian rainforest. These flocks provide a model system for investigating how habitat heterogeneity influences non-trophic interactions and the subsequent social structure of forest-dependent mixed-species bird flocks. We analyse 21 flock interaction networks throughout a mosaic of primary forest, fragments of varying sizes and secondary forest (SF) at the Biological Dynamics of Forest Fragments Project in central Amazonian Brazil. Habitat type had a strong effect on network structure at the levels of both species and flock. Frequency of associations among species, as summarized by weighted degree, declined with increasing levels of forest fragmentation and SF. At the flock level, clustering coefficients and overall attendance positively correlated with mean vegetation height, indicating a strong effect of habitat structure on flock cohesion and stability. Prior research has shown that trophic interactions are often resilient to large-scale changes in habitat structure because species are ecologically redundant. By contrast, our results suggest that behavioural interactions and the structure of non-trophic networks are highly sensitive to environmental change. Thus, a more nuanced, system-by-system approach may be needed when thinking about the resiliency of ecological networks.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)