胸腺上皮细胞

胸腺上皮细胞

(查了两篇文章，下面是其中一篇Thymic microenvironments for T-cell repertoire formation的abstract部分，全文没有查到。我做了一下搬运工工作，可能翻译的不太准确，所以把原文也贴了一下。)

The recent discovery of thymoproteasomes, a molecular complex specifically expressed in cortical thymic epithelial cells (cTEC), has revealed a unique role of cTEC in cuing the further development of immature thymocytes in thymic cortex, possibly by displaying unique self-peptides that induce positive selection. Cortical thymocytes that receive TCR-mediated positive selection signals are destined to survive for further differentiation and are induced to express CCR7, a chemokine receptor. Being attracted to CCR7 ligands expressed by medullary thymic epithelial cells (mTEC), CCR7-expressing positively selected thymocytes relocate to thymic medulla. The medullary microenvironment displays another set of unique self-peptides for trimming positively selected T-cell repertoire to establish self-tolerance, via promiscuous expression of tissue-specific antigens by mTEC and efficient antigen presentation by dendritic cells. Recent results demonstrate that tumor necrosis factor (TNF) superfamily ligands, including receptor activating NF-kappaB ligand (RANKL), CD40L, and lymphotoxin, are produced by positively selected thymocytes and pivotally regulate mTEC development and thymic medulla formation.

在cTEC中特异表达的thymoproteasome表明cTEC对胸腺皮质中未成熟胸腺细胞的进一步发育有重要作用，这一作用是通过表达独特的自身肽引起阳性选择实现的。经过TCR介导的阳性选择的皮质胸腺细胞可以进入分化阶段并且被诱导表达CCR7。这些表达了CCR7的胸腺细胞被mTEC表达的CCRL7吸引重新定位于胸腺髓质。髓质微环境亦表达一类自身肽，通过mTEC随机表达TSA 和DC有效的抗原呈递，使阳性选择的T细胞形成自身耐受。