Department of Molecular Biosciences, Institute of Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States.
Department of Immunology, Mayo Clinic, Scottsdale, AZ, United States.
Front Immunol. 2021 Apr 22;12:676236. doi: 10.3389/fimmu.2021.676236. eCollection 2021.
Thymic epithelial cells (TECs) and hematopoietic antigen presenting cells (HAPCs) in the thymus microenvironment provide essential signals to self-reactive thymocytes that induce either negative selection or generation of regulatory T cells (Treg), both of which are required to establish and maintain central tolerance throughout life. HAPCs and TECs are comprised of multiple subsets that play distinct and overlapping roles in central tolerance. Changes that occur in the composition and function of TEC and HAPC subsets across the lifespan have potential consequences for central tolerance. In keeping with this possibility, there are age-associated changes in the cellular composition and function of T cells and Treg. This review summarizes changes in T cell and Treg function during the perinatal to adult transition and in the course of normal aging, and relates these changes to age-associated alterations in thymic HAPC and TEC subsets.
胸腺上皮细胞（TECs）和造血抗原呈递细胞（HAPCs）在胸腺微环境中为自身反应性胸腺细胞提供必需的信号，诱导阴性选择或调节性 T 细胞（Treg）的产生，这两者都是建立和维持终身中枢耐受所必需的。HAPCs 和 TECs 由多个亚群组成，它们在中枢耐受中发挥独特且重叠的作用。TEC 和 HAPC 亚群的组成和功能在整个生命周期中的变化可能对中枢耐受产生影响。与这种可能性相一致的是，T 细胞和 Treg 的细胞组成和功能随着年龄的增长而发生变化。本综述总结了围生期至成年过渡期以及正常衰老过程中 T 细胞和 Treg 功能的变化，并将这些变化与胸腺 HAPC 和 TEC 亚群的年龄相关改变相关联。
