Functional mature T cells are generated in the thymus. Thymic epithelial cells (TECs) provide the essential microenvironment for T cell development and maturation. According to their function and localization, TECs are roughly divided into cortical TECs (cTECs) and medullary TECs (mTECs), which are responsible for positive and negative selection, respectively. This review summarizes the current understanding of TEC biology, the identification of fetal and adult bipotent TEC progenitors, and the signaling pathways that control the development and maturation of TECs. The understanding of the ontogeny, differentiation, maturation and function of cTECs lags behind that of mTECs. Better understanding TEC biology will provide clues about TEC development and the applications of thymus engineering.

在胸腺中生成功能成熟的T细胞。胸腺上皮细胞（TECs）为T细胞发育和成熟提供了必不可少的微环境。根据其功能和位置，TEC大致分为皮质TEC（cTEC）和髓质TEC（mTEC），分别负责阳性和阴性选择。这篇综述总结了对TEC生物学的当前理解，胎儿和成人双能TEC祖细胞的鉴定以及控制TEC发育和成熟的信号通路。对cTECs的个体发育，分化，成熟和功能的了解落后于mTECs。更好地了解TEC生物学将为TEC开发和胸腺工程应用提供线索。