Rossi Simona W, Chidgey Ann P, Parnell Sonia M, Jenkinson William E, Scott Hamish S, Boyd Richard L, Jenkinson Eric J, Anderson Graham
MRC Centre for Immune Regulation, Institute for Biomedical Research, University of Birmingham Medical School, Birmingham, UK.
Eur J Immunol. 2007 Sep;37(9):2411-8. doi: 10.1002/eji.200737275.
Cortical and medullary epithelium represent specialised cell types that play key roles in thymocyte development, including positive and negative selection of the T cell repertoire. While recent evidence shows that these epithelial lineages share a common embryonic origin, the phenotype and possible persistence of such progenitor cells in the thymus at later stages of development remain controversial. Through use of a panel of reagents including the putative progenitor marker Mts24, we set out to redefine the stages in the development of thymic epithelium. In the early embryonic day (E)12 thymus anlagen we find that almost all epithelial cells are uniformly positive for Mts24 expression. In addition, while the thymus at later stages of development was found to contain distinct Mts24(+) and Mts24(-) epithelial subsets, thymus grafting experiments show that both Mts24(+) and Mts24(-) epithelial subsets share the ability to form organised cortical and medullary thymic microenvironments that support T cell development, a function shown previously to be lost in the Mts24(-) cells by E15 when lower cell doses were used. Our data help to clarify stages in thymic epithelial development and provide important information in relation to currently used markers of epithelial progenitors.
皮质和髓质上皮代表了特殊的细胞类型，它们在胸腺细胞发育中发挥关键作用，包括T细胞库的阳性和阴性选择。虽然最近的证据表明这些上皮谱系具有共同的胚胎起源，但这种祖细胞在发育后期胸腺中的表型和可能的持续性仍存在争议。通过使用包括假定的祖细胞标志物Mts24在内的一组试剂，我们着手重新定义胸腺上皮发育的阶段。在胚胎早期第12天（E12）的胸腺原基中，我们发现几乎所有上皮细胞的Mts24表达均呈均匀阳性。此外，虽然发现在发育后期的胸腺中含有不同的Mts24(+)和Mts24(-)上皮亚群，但胸腺移植实验表明，Mts24(+)和Mts24(-)上皮亚群都具有形成支持T细胞发育的有组织的皮质和髓质胸腺微环境的能力，以前的研究表明，当使用较低细胞剂量时，E15时Mts24(-)细胞会丧失这一功能。我们的数据有助于阐明胸腺上皮发育的阶段，并提供有关目前使用的上皮祖细胞标志物的重要信息。
