The epithelial architecture of the thymus fosters growth, differentiation, and T cell receptor repertoire selection of large numbers of immature T cells that continuously feed the mature peripheral T cell pool. Failure to build or to maintain a proper thymus structure can lead to defects ranging from immunodeficiency to autoimmunity. There has been long-standing interest in unraveling the cellular and molecular basis of thymus organogenesis. Earlier studies gave important morphological clues on thymus development. More recent cell biological and genetic approaches yielded new and conclusive insights regarding the germ layer origin of the epithelium and the composition of the medulla as a mosaic of clonally derived islets. The existence of epithelial progenitors common for cortex and medulla with the capacity for forming functional thymus after birth has been uncovered. In addition to the thymus in the chest, mice can have a cervical thymus that is small, but functional, and produces T cells only after birth. It will be important to elucidate the pathways from putative thymus stem cells to mature thymus epithelial cells, and the properties and regulation of these pathways from ontogeny to thymus involution.

中文翻译：

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胸腺器官发生。

胸腺的上皮结构促进了大量不成熟T细胞的生长，分化和T细胞受体库选择，这些不成熟T细胞不断地为成熟的外周T细胞池提供营养。无法建立或维持适当的胸腺结构会导致从免疫缺陷到自身免疫的缺陷。长期以来，人们一直在了解胸腺器官发生的细胞和分子基础。早期的研究提供了关于胸腺发育的重要形态学线索。最近的细胞生物学和遗传学方法对上皮的胚层起源和作为克隆来源的胰岛的镶嵌的髓质的组成产生了新的和决定性的见解。已经发现存在皮质和髓质常见的上皮祖细胞，其具有在出生后形成功能性胸腺的能力。除了胸部的胸腺外，小鼠的颈胸腺也小，但功能正常，仅在出生后才产生T细胞。阐明从假定的胸腺干细胞到成熟的胸腺上皮细胞的途径，以及从个体发育到胸腺退化的这些途径的性质和调控，将是重要的。