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La tolerancia de las células T CD8 es el resultado de la expulsión de células autoreactivas inmaduras del timo
Mohamed Elsherif Badr1, Zhongmei Zhang1, Xuguang Tai1
1Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Science (New York, N.Y.)
|November 2, 2023
Resumen
La tolerancia de las células T CD8 surge del desalojo tímico prematuro de los timocitos autorreactivos, no de la deleción clonal. Este proceso permite que las células T CD8 inmaduras maduren en células autotolerantes en la periferia.
Área de la Ciencia:
- Inmunología
- Biología de las células T
- Mecanismos de auto tolerancia
Sus antecedentes:
- El entendimiento actual postula que la tolerancia de las células T CD8 resulta de la eliminación de los timocitos autorreactivos en el timo.
- Este proceso, conocido como deleción clonal, impide que las células T maduras ataquen los propios tejidos del cuerpo.
Objetivo del estudio:
- Investigar el mecanismo preciso que subyace a la tolerancia de las células T CD8 en ratones.
- Desafiar el modelo prevaleciente de la deleción clonal como el único determinante de la autotolerancia de las células T CD8.
Principales métodos:
- Se utilizaron modelos de ratón para estudiar el desarrollo y la tolerancia de las células T.
- Se analizó la expresión génica, centrándose específicamente en el represor de transcripción Gfi1 y el receptor de esfingosina-1-fosfato-1 (S1P1).
- Investigó el papel de la señalización del receptor de células T (TCR) en el desarrollo y la salida de timocitos.
Principales resultados:
- Se demostró que la tolerancia de las células T CD8 en ratones está mediada por el desalojo tímico prematuro de los timocitos autorreactivos inmaduros.
- Identificó la desregulación inducida por la señalización del receptor de células T (TCR) de Gfi1 como el desencadenante de este desalojo.
- Se demostró que la regulación a la baja de Gfi1 conduce a la expresión de S1P1, facilitando la migración de timocitos inmaduros a la periferia.
- Se observó que estas células T CD8 perifericamente maduras son autotolerantes, a pesar de tener TCR autorreactivas.
Conclusiones:
- Desafió la visión tradicional de la deleción clonal en la tolerancia de las células T CD8.
- El desalojo tímico prematuro se ha establecido como un mecanismo nuevo y crítico para establecer la tolerancia de las células T CD8.
- Destacó la importancia de la maduración periférica para las células T CD8 autotolerantes con potencial autorreactivo.
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