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Memórias do Instituto Oswaldo Cruz
Fundação Oswaldo Cruz, Fiocruz
ISSN: 1678-8060 EISSN: 1678-8060
Vol. 92, No. s2, 1997, pp. 233-235
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Bioline Code: oc97194
Full paper language: English
Document type: Research Article
Document available free of charge
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Memórias do Instituto Oswaldo Cruz, Vol. 92, No. s2, 1997, pp. 233-235
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Nitric Oxide Mediates The Microbicidal Activity Of Eosinophils
Oliveira, Sandra H.P.; Fonseca, Simone G.; Romao, Pedro R.T.; Ferreira, Sergio H. & Cunha, Fernando Q.
Abstract
There are several experimental evidences that nitric oxide (NO) is
involved in the microbicidal activity of macrophages against a number of
intracellular pathogens including Leishmania major, Trypanozoma cruzi,
Toxoplasma gondii. It is also well known that eosinophils (EO) have
microbicidal activity against many parasites such as Schistosoma
mansoni, Trichinella spiralis, T. cruzi and L. amazonensis. The
purpose of this study was to investigate if NO is involved in the
microbicidal activity of EO against L. major. Eosinophils harvested
from peritoneal cavity of rats released spontaneously after 24 and 48 hr a
small amount of nitrite. This release was enhanced by the treatment of
cells with IFN-gamma (200 IU/ml). This release was blocked by addition of
the NO synthase inhibitor, L-NIO (100 mM) into the culture. To determinate
the leishmanicidal activity of eosinophils the parasites were incubated with
activated eosinophils with IFN-gamma and the ability of surviving parasites
to incorporate [3H]thymidine was evaluated. IFN-gamma-activated eosinophils
were able to kill L. major and to release high levels of nitrite. The
ability to destroy L. major and the release of NO were completely
blocked by L-NIO. These results indicate that activated eosinophils release
NO which is involved in the microbicidal activity of these cells against
L. major.
Keywords
nitric oxide - eosinophils - microbicidal activity - Leishmania major
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