The extent of central T cell tolerance is determined by the diversity of self-antigens that developing thymocytes ‘see’ on thymic antigen-presenting cells (APCs). Here, focusing on insights from the past decade, we review the functional adaptations of medullary thymic epithelial cells, thymic dendritic cells and thymic B cells for the purpose of tolerance induction. Their distinct cellular characteristics range from unconventional phenomena, such as promiscuous gene expression or mimicry of peripheral cell types, to strategic positioning in distinct microenvironments and divergent propensities to preferentially access endogenous or exogenous antigen pools. We also discuss how ‘tonic’ inflammatory signals in the thymic microenvironment may extend the intrathymically visible ‘self’ to include autoantigens that are otherwise associated with highly immunogenic peripheral environments.

中枢 T 细胞耐受的程度取决于正在发育的胸腺细胞在胸腺抗原呈递细胞 (APC) 上“看到”的自身抗原的多样性。在此，我们重点回顾了过去十年的见解，回顾了胸腺髓质上皮细胞、胸腺树突状细胞和胸腺 B 细胞为了诱导耐受而进行的功能适应。它们独特的细胞特征包括非常规现象，例如混杂的基因表达或外周细胞类型的模仿，到不同微环境中的战略定位以及优先访问内源或外源抗原库的不同倾向。我们还讨论了胸腺微环境中的“补品”炎症信号如何扩展胸腺内可见的“自身”，以包括与高免疫原性外周环境相关的自身抗原。