Kabelitz Dieter, Wesch Daniela, Oberg Hans-Heinrich
Institute of Immunology, UK S-H Campus Kiel, Michaelisstr. 5, D-24105 Kiel, Germany.
Crit Rev Immunol. 2006;26(4):291-306. doi: 10.1615/critrevimmunol.v26.i4.10.
Regulatory T cells (Treg) are characterized by high-level surface CD25 and intracellular FoxP3 expression. Treg are instrumental in the maintenance of peripheral immune tolerance and the control of adaptive immune responses. Naturally occuring Treg suppress T-cell responses by cell contact-dependent mechanisms, whereas induced regulatory cells, including Tr1 cells, secrete inhibitory cytokines such as transforming growth factor (TGF)-beta and interleukin-10. The interplay between Treg and antigen-responsive T cells is modulated by dendritic cells (DC). Whereas immature myeloid precursors of DC suppress T-cell activation per se and immature DC support Treg development, mature DC can override Treg-mediated suppression in vitro and in vivo. Mature DC activated through Toll-like receptor (TLR) pattern recognition receptors produce proinflammatory cytokines, including interleukin-6, which render responder T cells refractory to the suppressive effect of Treg. In addition, Treg also express certain TLR, and the activation and/or suppressor function of Treg is modulated directly by the respective ligands. In this review, we discuss current models of how signals delivered through innate immune receptors in response to pathogen-associated molecular patterns affect adaptive immune responses via modulation of Treg function.
调节性T细胞（Treg）的特征在于高水平的表面CD25表达和细胞内FoxP3表达。Treg在维持外周免疫耐受和控制适应性免疫反应中发挥着重要作用。天然存在的Treg通过细胞接触依赖性机制抑制T细胞反应，而诱导性调节细胞，包括Tr1细胞，则分泌抑制性细胞因子，如转化生长因子（TGF）-β和白细胞介素-10。Treg与抗原反应性T细胞之间的相互作用受树突状细胞（DC）调节。DC的未成熟髓样前体本身抑制T细胞活化，未成熟DC支持Treg发育，而成熟DC在体外和体内均可克服Treg介导的抑制作用。通过Toll样受体（TLR）模式识别受体激活的成熟DC产生促炎细胞因子，包括白细胞介素-6，使反应性T细胞对Treg的抑制作用产生抗性。此外，Treg也表达某些TLR，Treg的激活和/或抑制功能直接受相应配体的调节。在本综述中，我们讨论了当前的模型，即通过先天免疫受体传递的信号如何响应病原体相关分子模式，通过调节Treg功能来影响适应性免疫反应。
