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Avalia????o do papel de macr??fagos murinos na infec????o por micobact??rias ambientais

By Juliana Perrone Bezerra de Menezes

Abstract

Micobact??rias ambientais podem ser encontradas em ??gua, solo, poeira, alimentos e animais. A import??ncia do estudo dessas micobact??rias tem aumentado nos ??ltimos anos, principalmente, devido a predisposi????o de pacientes com imunodefici??ncia ?? infec????o por essas esp??cies de micobact??ria. Al??m disso, a exposi????o a micobact??rias ambientais pode constituir um dos fatores associados ?? baixa efic??cia da imuniza????o com a vacina BCG. As manifesta????es da doen??a, assim como a manuten????o da infec????o micobateriana, dependem da intera????o entre a micobact??ria e o sistema imune do hospedeiro. O presente trabalho teve como objetivo avaliar a resposta de macr??fagos peritoneais de camundongos suscept??veis BALB/c infectados com M intracellulare ou M fortuitum. Macr??fagos peritoneais de camundongos BALB/c foram infectados por M intracellulare ou M fortuitum e as diferen??as entre essas duas esp??cies quanto ?? capacidade de infectar e sobreviver no interior de macr??fagos prim??rios, tratados ou n??o com IFN-y, e produzir ??xido n??trico foram avaliadas. Foi observado que os macr??fagos infectados com M fortuitum apresentam um maior percentual de c??lulas infectadas que aqueles infectados com M. intracellulare, ap??s 4, 24 e 48 horas de infec????o. Entretanto, tanto M. fortuitum quanto M intracellulare s??o capazes de sobreviver no interior de macr??fagos peritoneais, pois n??o h?? altera????o da carga bacilar dessa duas esp??cies de micobact??ria ao longo da infec????o. Observamos ainda que M. intracellulare induziu uma maior produ????o de ??xido n??trico por macr??fagos prim??rios infectados e tratados por IFN-y que M fortuitum. No entanto, o pr??-tratamento com IFN-y n??o alterou o percentual de c??lulas infectadas nem a viabilidade de M intracellulare ou M. fortuitum. Os dados obtidos neste trabalho mostram que, in vitro, M. fortuitum e M. intracellulare interagem de formas distintas, levando ?? diferentes respostas do macr??fago e a destinos intracelulares distintos. Al??m disso, mostramos que M intracellulare e M. fortuitum s??o resistentes ao ??xido n??trico produzido por macr??fagos ap??s ativa????o por IFN-y.Environmental mycobacteria are found in water, soil, dust, food and animals. Environmental Mycobacterium importance has increased in the last few years, mostly because of immunodeficient patient predisposition to infection. Moreover, exposure to environmental mycobacteria could be associated to low levels of protection induced by immunization with BCG. Disease manifestations as well as infection outcome depend on interaction between mycobacteria and host immune system. The goal of this work was to evaluate peritoneal macrophage response, from the susceptible BALB/c mice, to M. intracellulare or M. fortuitum infection. Peritoneal inflammatory macrophages, pre-activated or not with IFN-y, were infected by M. intracellulare or M fortuitum and diferences between these two species related to the capacity to infect macrophages, to survive intracellularly and to induce NO production were evaluated. It was observed that the percentage of M. fortuitum-xn??QoXQ?? cells was higher related to M. intracellulare-m??ecie?? ones, after 4, 24 and 48 hours of infection. In addition, both M. fortuitum and M. intracellulare presented the ability to survive in peritoneal macrophages. It was also observed that in response to IFN-y activation, M. intracellulare induced higher NO production thanM fortuitum. However, pre-activation with IFN-y did not modify, neither the percentage of M. intracellulare and M. fortuitum infected cells, nor intracellular bacillum survival. These data demonstrate that, in vitro., M. fortuitum and M. intracellulare differently interact with macrophages, inducing diferent macrophage reponses and that both M. intracellulare and M fortuitum are resistant to NO production upon IFN-y activation

Topics: Micobact??rias ambientais, M intracellulare, M. fortuitum, Macr??fago, Environmental mycobacteria, M. intracellulare, M. fortuitum, Macrophage
Year: 2005
OAI identifier: oai:agregador.ibict.br.RI_FIOCRUZ:oai:localhost:icict/5914
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