Lai Yein-Gei, Hou Mau-Sheng, Hsu Yaw-Wen, Chang Chin-Ling, Liou Yae-Huei, Tsai Ming-Han, Lee Fan, Liao Nan-Shih
Graduate Institute of Life Sciences, National Defense Medical Center, Taipei. Taiwan.
J Immunol. 2008 Mar 15;180(6):3757-65. doi: 10.4049/jimmunol.180.6.3757.
Mice devoid of the IL-15 system lose over 90% of CD8alphaalpha(+) TCRalphabeta and TCRgammadelta intestinal intraepithelial lymphocytes (iIELs). Previous work revealed that IL-15Ralpha and IL-15 expressed by parenchymal cells, but not by bone marrow-derived cells, are required for normal CD8alphaalpha(+) iIEL homeostasis. However, it remains unclear when and how the IL-15 system affects CD8alphaalpha(+) iIELs through their development. This study found that IL-15Ralpha is dispensable for the thymic stage of CD8alphaalpha(+) TCRalphabeta and TCRgammadelta iIEL development but is required for the maintenance and/or differentiation of the putative lineage marker negative precursors in the intestinal epithelium, especially for the most mature CD8 single positive subset. Moreover, the IL-15 system directly supports the survival of mature CD8alphaalpha(+) iIEL in vivo. Taken together, this study suggests that regulation of CD8alphaalpha(+) iIEL homeostasis by the IL-15 system does not occur in the thymus but involves mature cells and putative precursors in the intestine.
缺乏白细胞介素-15（IL-15）系统的小鼠会失去超过90%的CD8αα(+)TCRαβ和TCRγδ肠道上皮内淋巴细胞（iIELs）。先前的研究表明，实质细胞而非骨髓来源的细胞表达的IL-15Rα和IL-15是正常CD8αα(+)iIEL稳态所必需的。然而，IL-15系统在何时以及如何通过其发育影响CD8αα(+)iIELs仍不清楚。本研究发现，IL-15Rα对于CD8αα(+)TCRαβ和TCRγδ iIEL发育的胸腺阶段是可有可无的，但对于肠道上皮中假定的谱系标记阴性前体的维持和/或分化是必需的，特别是对于最成熟的CD8单阳性亚群。此外，IL-15系统在体内直接支持成熟CD8αα(+)iIEL的存活。综上所述，本研究表明，IL-15系统对CD8αα(+)iIEL稳态的调节并非发生在胸腺中，而是涉及肠道中的成熟细胞和假定的前体。
