Resumen
El papel del óxido nítrico (ON) como regulador de la activación de los linfocitos T en los ratones fue evaluado in vitro mediante el uso de linfocitos T colaboradores clonados y macrófagos peritoneales como células presentadoras de antígeno (CPA). Luego de agregar el antígeno, los linfocitos T colaboradores activados (Th1) indujeron la producción de ON en las CPA. A su vez, esto previno la proliferación de las células T. La producción de interferón gamma (IFN-γ) por las células T fue esencial para la inducción de ON, confirmando la activación de las células T por las CPA. No fue sorprendente hallar que las células Th2 activadas no pudieron inducir la producción de ON y proliferaron libremente a menos que se agregara IFN-γ a los cultivos en forma exógena. Para examinar si el papel inhibitorio del ON sobre las células T también podía estar involucrado en las respuestas inmunes, se activaron con el inmunógeno in vitro los esplenocitos de ratones inmunizados deficientes en IFN-γ. Fue necesaria la presencia de IFN-γ exógeno para inducir la producción de ON e inhibir la proliferación. Estos resultados indican que durante la inducción de las respuestas tipo Th1, pero no las de tipo Th2, el ON tiene un papel regulatorio mediante la inhibición de la activación T, con lo cual reduce la intensidad de la respuesta inmune subsiguiente. Este concepto podría aplicarse a las respuestas inmunitarias en general.
Palabras clave
Oxido nítrico, interferón γ, encefalomielitis, linfocito T, presentación antigénica.
Clasificación en siicsalud
Artículos originales> Expertos del Mundo>
página www.siicsalud.com/des/des029/02906010.htm
Especialidades
Principal: Neurología
Relacionadas: Clínica Médica, Inmunología
Enviar correspondencia a:
Roel C. van der Veen, Ph.D. Department of Neurology, University of Southern California School of Medicine, Los Angeles, CA, EE.UU.
Patrocinio y reconocimiento
Este trabajo fue financiado en parte por la Multiple Sclerosis Society (NuevaYork). El autor agradece a T.A. Dietlin por la excelente asistencia técnica.
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NITRIC OXIDE REGULATES COGNATE T-LYMPHOCYTE ACTIVATION
Abstract
The role of nitric oxide (NO) as a regulator of T lymphocyte activation in mice was examined in vitro, using cloned T-helper lymphocytes and peritoneal macrophages as antigen-presenting cells (APC). After the addition of antigen, the activated T-helper type 1 (Th1) cells induced NO production in the APC. This in turn prevented proliferation of the T cells. Production of IFN-γ by the T cells was essential for the induction of NO, confirming the activation of the T cells by the APC. Not surprisingly, activated Th2 cells could not induce NO production, and proliferated freely, unless IFN-γ was added to the cultures exogenously. To examine whether the T cell inhibitory role of NO could also be involved in immune responses, spleen cells from immunized IFN- γ-deficient mice were activated with their immunogen in vitro. Indeed, the presence of exogenous IFN- γ was required to induce NO production and inhibit proliferation. These results indicate that during the induction of Th1, but not Th2-type immune responses, NO plays a regulatory role, inhibiting T cell activation, thereby reducing the intensity of the ensuing immune response. This concept may apply to immune responses in general.
Key words
Nitric oxide, interferon-γ, encephalomyelitis, T lymphocyte, antigen presentation.
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Bibliografía del artículo
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