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dc.contributor.authorSilva, Tania Regina Marques da
dc.contributor.authorFreitas, Juliana Ribeiro de
dc.contributor.authorSilva, Queilan Chagas
dc.contributor.authorFigueira, Claudio Pereira
dc.contributor.authorRoxo, Eliana
dc.contributor.authorLeao, Sylvia Cardoso [UNIFESP]
dc.contributor.authorFreitas, Luiz Antonio Rodrigues de
dc.contributor.authorVeras, Patricia Sampaio Tavares
dc.identifier.citationInfection and Immunity. Washington: Amer Soc Microbiology, v. 70, n. 10, p. 5628-5634, 2002.
dc.description.abstractThe virulence of different isolates of Mycobacterium has been associated with two morphologically distinguishable colonial variants: opaque (SmOp) and transparent (SmTr). in this report we used an in vitro assay to compare macrophage (Mphi) responses to SmOp and SmTr Mycobacterium fortuitum variants, taking advantage of the fact that these variants were derived from the same isolate. Cells preactivated or not with gamma interferon (IFN-gamma) were infected with SmOp or SmTr M. fortuitum. We showed that SmOp and SmTr induced different levels of nitric oxide (NO) production by IFN-gamma-stimulated Mphi. Indeed, the amount of IFN-gamma-induced NO production by J774 cells was 4.8 to 9.0 times higher by SmOp (23.1 to 37.7 muM) compared to SmTr infection (3.9 to 4.8 muM) (P = 0.0332), indicating that virulent SmTr bacilli restricted NO production. in addition, IFN-gamma-induced NO production by Mphi was higher when correlated with reduction of only avirulent SmOp bacillus viability. SNAP (S-nitroso-N-acetyl-DL-penicillamine)-induced NO production did not modify SmTr viability, indicating its resistance to nitrogen radicals. Electron microscopy studies were performed to evaluate the capacity of phagosomes to fuse with lysosomes labeled with bovine serum albumin-colloidal gold particles. By 24 h postinfection, 69% more phagosome-containing SmOp variant had fused with lysosomes compared to the SmTr-induced phagosomes. in conclusion, these data indicate that virulent SmTr bacilli may escape host defense by restricting IFN-gamma-induced NO production, resisting nitrogen toxic radicals, and limiting phagosome fusion with lysosomes.en
dc.publisherAmer Soc Microbiology
dc.relation.ispartofInfection and Immunity
dc.rightsAcesso aberto
dc.titleVirulent Mycobacterium fortuitum restricts NO production by a gamma interferon-activated J774 cell line and phagosome-lysosome fusionen
dc.contributor.institutionFIOCRUZ BA R Valdemar Falcao
dc.contributor.institutionUniversidade Federal da Bahia (UFBA)
dc.contributor.institutionEscola Bahiana Med & Saude Publ SSA BA
dc.contributor.institutionUniversidade de São Paulo (USP)
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)
dc.description.affiliationFIOCRUZ BA R Valdemar Falcao, Lab Pathol & Cellular Biol, CPqGM, BR-40295001 Salvador, BA, Brazil
dc.description.affiliationUniv Fed Bahia, Fac Med, BR-41170290 Salvador, BA, Brazil
dc.description.affiliationEscola Bahiana Med & Saude Publ SSA BA, Salvador, BA, Brazil
dc.description.affiliationSP SP, Inst Biol, São Paulo, Brazil
dc.description.affiliationUniversidade Federal de São Paulo, UNIFESP EPM, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, São Paulo, Brazil
dc.description.affiliationUnifespUniversidade Federal de São Paulo, UNIFESP EPM, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, São Paulo, Brazil
dc.description.sourceWeb of Science
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