Navegando por Palavras-chave "Major histocompatibility complex"

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    Analysis of CD83 antigen expression in human breast fibroadenoma and adjacent tissue
    (Associação Paulista de Medicina - APM, 2011-12-01) Borges, Marcus Nascimento [UNIFESP]; Facina, Gil [UNIFESP]; Silva, Ismael Dale Cotrim Guerreiro da [UNIFESP]; Waitzberg, Angela Flávia Logullo [UNIFESP]; Nazário, Afonso Celso Pinto [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    CONTEXT AND OBJECTIVE: Dendritic cell maturation is considered essential for starting an immune response. The CD83 antigen is an important marker of dendritic cell maturation. The objectives here were to analyze CD83 antigen expression in human breast fibroadenoma and breast tissue adjacent to the lesion and to identify clinical factors that might influence this expression. DESIGN AND SETTING: This was a retrospective study at a public university hospital, in which 29 histopathological samples of breast fibroadenoma and adjacent breast tissue, from 28 women of reproductive age, were analyzed. METHODS: The immunohistochemistry method was used to analyze the cell expression of the antigen. The antigen expression in the cells was evaluated by means of random manual counting using an optical microscope. RESULTS: Positive expression of the CD83 antigen in the epithelial cells of the fibroadenoma (365.52; standard deviation ± 133.13) in relation to the adjacent breast tissue cells (189.59; standard deviation ± 140.75) was statistically larger (P < 0.001). Several clinical features were analyzed, but only parity was shown to influence CD83 antigen expression in the adjacent breast tissue, such that positive expression was more evident in nulliparous women (P = 0.042). CONCLUSIONS: The expression of the CD83 antigen in the fibroadenoma was positive and greater than in the adjacent breast tissue. Positive expression of the antigen in the adjacent breast tissue was influenced by parity, and was significantly more evident in nulliparous women.
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    Immunodominance: a new hypothesis to explain parasite escape and host/parasite equilibrium leading to the chronic phase of Chagas' disease?
    (Associação Brasileira de Divulgação Científica, 2009-03-01) Rodrigues, Mauricio Martins [UNIFESP]; Alencar, Bruna Cunha Gondim de [UNIFESP]; Claser, Carla [UNIFESP]; Tzelepis, Fanny [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Intense immune responses are observed during human or experimental infection with the digenetic protozoan parasite Trypanosoma cruzi. The reasons why such immune responses are unable to completely eliminate the parasites are unknown. The survival of the parasite leads to a parasite-host equilibrium found during the chronic phase of chagasic infection in most individuals. Parasite persistence is recognized as the most likely cause of the chagasic chronic pathologies. Therefore, a key question in Chagas' disease is to understand how this equilibrium is established and maintained for a long period. Understanding the basis for this equilibrium may lead to new approaches to interventions that could help millions of individuals at risk for infection or who are already infected with T. cruzi. Here, we propose that the phenomenon of immunodominance may be significant in terms of regulating the host-parasite equilibrium observed in Chagas' disease. T. cruzi infection restricts the repertoire of specific T cells generating, in some cases, an intense immunodominant phenotype and in others causing a dramatic interference in the response to distinct epitopes. This immune response is sufficiently strong to maintain the host alive during the acute phase carrying them to the chronic phase where transmission usually occurs. At the same time, immunodominance interferes with the development of a higher and broader immune response that could be able to completely eliminate the parasite. Based on this, we discuss how we can interfere with or take advantage of immunodominance in order to provide an immunotherapeutic alternative for chagasic individuals.