831 resultados para innate and adaptive immunity


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Paracoccidioides brasiliensis causes paracoccidioidomycosis (PCM) that is one of the most prevalent systemic human mycoses in Latin America. Armadillos show a high incidence of PCM infection and could, therefore, be a natural reservoir for this fungus. In this study were compared the virulence profiles of isolates obtained from nine-banded armadillos (Dasypus novemcinctus) (PbT1 and PbT4) and isolates from PCM patients (Pb265 and Bt83). Pathogenicity was evaluated by fungal load and analysis of colony morphology. Immunity against the fungus was tested by delayed type hypersensitivity test (DTH) and antibody quantification by ELISA. The higher virulence of PbT1 and PbT4 was suggested by higher fungal load in spleen and lungs. Armadillo isolates and Bt83 presented a cotton-like surface contrasting with the cerebriform appearance of Pb265. All isolates induced cellular and humoral immune responses in infected BALB/c mice. DTH reactions were similarly induced by the four isolates, however, a great variability was observed in specific antibody levels, being the highest ones induced by Bt83 and PbT4. The present work confirms that armadillos harbor P. brasiliensis, whose multiplication and induced immunity in experimentally infected mice are heterogeneous, resembling the behavior of isolates from human PCM. This study reinforces the possibility that armadillos play an important role in the biological cycle of this pathogen.

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P>In this study, we investigated the characteristics of the infection and subsequent immunity induced by Strongyloides venezuelensis in Lewis rats. Animals were infected with 4000 L3 of S. venezuelensis and number of eggs per gram of faeces indicated an acute phase around day 8 and a recovery phase around day 32 after infection. A strong Th2 polarization during recovery phase was ascertained by a significant increase in IgG1 and IgE compared with that in the acute period. A shift in the cytokine profile confirmed these findings. A predominant production of IFN-gamma during the acute phase was followed by IL-10 production during recovery. Together these findings show that experimental infection of Lewis rats with S. venezuelensis presents a kinetics of parasite establishment and immunity similar to that described in other models of helminthic infection.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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INTRODUÇÃO: Comprometimentos na marcha de pacientes com paralisia supranuclear progressiva (PSP) podem aumentar o risco de quedas durante o andar, especialmente em ambientes complexos. OBJETIVO: Descrever o comportamento locomotor de uma paciente com PSP, nas condições de marcha livre e marcha adaptativa. MATERIAIS E MÉTODOS: Estudo de caso de uma paciente com PSP (71 anos). Para análise cinemática, nas condições de marcha livre, com obstáculo baixo e alto, uma câmera digital registrou uma passada completa da paciente. RESULTADOS: Com o aumento da complexidade do ambiente (marcha livre, obstáculo baixo e alto, respectivamente), foi observada diminuição do comprimento do passo (0,37 ± 0,07; 0,30 ± 0,07; 0,26 ± 0,06 m), do comprimento da passada (0,71 ± 0,11; 0,58 ± 0,15; 0,47 ± 0,07 m) e da velocidade da passada (0,55 ± 0,14; 0,43 ± 0,11; 0,36 ± 0,11 m/s). Aumento progressivo ocorreu na duração do duplo suporte da passada livre (29,47%) para a passada antes do obstáculo alto (41,11%). Observou-se, ainda, ligeira diminuição na distância vertical pé/obstáculo alto (membro/abordagem: 7,18 ± 1,88; e membro/suporte: 8,84 ± 2,57 cm) em relação ao obstáculo baixo (membro de abordagem: 8,86 ± 1,88; e membro de suporte: 11,67 ± 2,09 cm). CONCLUSÃO: A PSP afetou de forma evidente a marcha da paciente. Inflexibilidade para a adaptação da marcha às demandas do ambiente foi observada durante a aproximação e a transposição dos obstáculos, o que pode aumentar o risco de tropeços e quedas.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The alcoholic liver cirrhosis usually causes overall immunological changes which might be attributed to either the hepatic disease itself, to ethanol action and/or to malnourishment of the patient. These immune abnormalities comprise both cellular and humoral immunity, consisting of increased immunoglobulin levels, depressed late-skin response to antigens, lowered proliferative response of lymphocytes to mitogens, lower plasma levels of complement proteins (C3 and C4) and by either lower (IL2 and gamma IF) or increased (IL1, TNF, IL6 and IL8) cytokine levels. Parallel to the systemic immune suppression found in most patients, there is also a concomitant local, genetically based, immune stimulation at the liver level which leads to hepatic self-aggression. The systemic immune-suppression could be responsible for periodical infections or neoplasia found in these patients. The possible factors for the immune exhaustion are: a) lower hepatic clearance of toxins and/or bacteria; b) lower hepatic synthesis of complement components; c) cytokines (IL2 and gamma IF) deficiencies, and d) deficiencies of nutrients related to the antioxidant and/or immune defense mechanisms. The immune stimulation of the liver self aggression is characterized by the preferential migration of cytotoxic T cell and neutrophils to the liver, following stimulatory factors such as Mallory bodies, acetaldehyde and/or antibodies. Moreover, the local increase of cytokines (IL1, TNF, IL6 and IL8) levels would be liable for the local phagocyte chemotaxy (IL8) or part of liver injury (TNF) eased by the lower antioxidant defense of the cirrhotic liver.(ABSTRACT TRUNCATED AT 250 WORDS)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciência Animal - FMVA

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Pós-graduação em Zootecnia - FCAV