Antigenic stimulation is more efficient than LPS in inducing nitric oxide production by human mononuclear cells on the in vitro granuloma reaction in schistosomiasis
Braz. j. med. biol. res
; 32(11): 1437-45, Nov. 1999. graf
Article
en En
| LILACS
| ID: lil-248438
Biblioteca responsable:
BR1.1
RESUMO
Nitric oxide (NO) is an extremely important and versatile messenger in biological systems. It has been identified as a cytotoxic factor in the immune system, presenting anti- or pro-inflammatory properties under different circumstances. In murine monocytes and macrophages, stimuli by cytokines or lipopolysaccharide (LPS) are necessary for inducing the immunologic isoform of the enzyme responsible for the high-output production of NO, nitric oxide synthase (iNOS). With respect to human cells, however, LPS seems not to stimulate NO production in the same way. Addressing this issue, we demonstrate here that peripheral blood mononuclear cells (PBMC) obtained from schistosomiasis-infected patients and cultivated with parasite antigens in the in vitro granuloma (IVG) reaction produced more nitrite in the absence of LPS. Thus, LPS-induced nitrite levels are easily detectable, although lower than those detected only with antigenic stimulation. Concomitant addition of LPS and L-N-arginine methyl ester (L-NAME) restored the ability to produce detectable levels of nitrite, which had been lost with L-NAME treatment. In addition, LPS caused a mild decrease of the IVG reaction and its association with L-NAME was responsible for reversal of the L-NAME-exacerbating effect on the IVG reaction. These results show that LPS alone is not as good an NO inducer in human cells as it is in rodent cells or cell lines. Moreover, they provide evidence for interactions between LPS and NO inhibitors that require further investigation.
Texto completo:
1
Índice:
LILACS
Asunto principal:
Schistosoma mansoni
/
Esquistosomiasis
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Células Sanguíneas
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Técnicas In Vitro
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Lipopolisacáridos
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Granuloma
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Antígenos Helmínticos
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Óxido Nítrico
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Braz. j. med. biol. res
Asunto de la revista:
BIOLOGIA
/
MEDICINA
Año:
1999
Tipo del documento:
Article
/
Congress and conference