Please use this identifier to cite or link to this item: https://repositorio.ufba.br/handle/ri/7457
metadata.dc.type: Artigo de Periódico
Title: Virulent Mycobacterium fortuitum restricts no production by a gamma interferon-activated j774 cell line and phagosome-lysosome fusion
Other Titles: Infection and Immunity
Authors: Silva, Tânia Regina Marques da
Freitas, Juliana Ribeiro de
Silva, Queilan Chagas
Figueira, Cláudio Pereira
Roxo, Eliana
Leão, Sylvia Cardoso
Freitas, Luiz Antônio Rodrigues de
Veras, Patrícia Sampaio Tavares
metadata.dc.creator: Silva, Tânia Regina Marques da
Freitas, Juliana Ribeiro de
Silva, Queilan Chagas
Figueira, Cláudio Pereira
Roxo, Eliana
Leão, Sylvia Cardoso
Freitas, Luiz Antônio Rodrigues de
Veras, Patrícia Sampaio Tavares
Abstract: The 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 (Mφ) 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-γ) were infected with SmOp or SmTr M. fortuitum. We showed that SmOp and SmTr induced different levels of nitric oxide (NO) production by IFN-γ-stimulated Mφ. Indeed, the amount of IFN-γ-induced NO production by J774 cells was 4.8 to 9.0 times higher by SmOp (23.1 to 37.7 μM) compared to SmTr infection (3.9 to 4.8 μM) (P = 0.0332), indicating that virulent SmTr bacilli restricted NO production. In addition, IFN-γ-induced NO production by Mφ 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-γ-induced NO production, resisting nitrogen toxic radicals, and limiting phagosome fusion with lysosomes.
URI: http://www.repositorio.ufba.br/ri/handle/ri/7457
Issue Date: Oct-2002
Appears in Collections:Artigo Publicado em Periódico (Biologia)

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