Xiong Na, Raulet David H
Department of Molecular and Cell Biology, Cancer Research Laboratory, University of California, Berkeley, CA, USA.
Immunol Rev. 2007 Feb;215:15-31. doi: 10.1111/j.1600-065X.2006.00478.x.
Two main lineages of T cells develop in the thymus: those that express the alphabeta T-cell receptor (TCR) and those that express the gammadelta TCR. Whereas the development, selection, and peripheral localization of newly differentiated alphabeta T cells are understood in some detail, these processes are less well characterized in gammadelta T cells. This review describes research carried out in this laboratory and others, which addresses several key aspects of gammadelta T-cell development, including the decision of precursor cells to differentiate into the gammadelta versus alphabeta lineage, the ordered differentiation over the course of ontogeny of functional gammadelta T-cell subsets expressing distinct TCR structures, programming of ordered Vgamma gene rearrangement in the thymus, including a molecular switch that ensures appropriate Vgamma rearrangements at the appropriate stage of development, positive selection in the thymus of gammadelta T cells destined for the epidermis, and the acquisition by developing gammadelta T cells of cues that determine their correct localization in the periphery. This research suggests a coordination of molecularly programmed events and cellular selection, which enables specialization of the thymus for production of distinct T-cell subsets at different stages of development.
T细胞的两个主要谱系在胸腺中发育：表达αβ T细胞受体（TCR）的谱系和表达γδ TCR的谱系。虽然新分化的αβ T细胞的发育、选择和外周定位已得到一定程度的详细了解，但这些过程在γδ T细胞中却不太清楚。本综述描述了在本实验室及其他实验室开展的研究，这些研究涉及γδ T细胞发育的几个关键方面，包括前体细胞分化为γδ谱系而非αβ谱系的决定、表达不同TCR结构的功能性γδ T细胞亚群在个体发育过程中的有序分化、胸腺中Vγ基因重排的有序编程，包括确保在发育的适当阶段进行适当Vγ重排的分子开关、注定迁移至表皮的γδ T细胞在胸腺中的阳性选择，以及发育中的γδ T细胞获得决定其在外周正确定位的信号。这项研究表明分子编程事件与细胞选择之间存在协调，这使得胸腺能够在发育的不同阶段专门产生不同的T细胞亚群。
