Intestinal intraepithelial lymphocytes (IELs) are a large and diverse population of lymphoid cells that reside between the intestinal epithelial cells (IECs) that form the intestinal mucosal barrier. Although IEL biology has traditionally focused on T cells, recent studies have identified several subsets of T cell receptor (TCR)-negative IELs with intriguing properties. New insight into the development, homeostasis, and functions of distinct IEL subsets has recently been provided. Additional studies have revealed intricate interactions between different IEL subsets, reciprocal interactions between IELs and IECs, and communication of IELs with immune cells that reside outside the intestinal epithelium. We review here sentinel functions of IELs in the maintenance of the mucosal barrier integrity, as well as how dysregulated IEL responses can contribute to pathology.

中文翻译：

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肠上皮内淋巴细胞：粘膜屏障的哨兵

肠上皮内淋巴细胞 (IEL) 是一个庞大且多样化的淋巴细胞群，位于形成肠粘膜屏障的肠上皮细胞 (IEC) 之间。尽管 IEL 生物学传统上专注于 T 细胞，但最近的研究发现了 T 细胞受体 (TCR) 阴性 IEL 的几个子集，它们具有有趣的特性。最近，人们对不同 IEL 子集的发育、稳态和功能有了新的见解。其他研究揭示了不同 IEL 子集之间复杂的相互作用、IEL 和 IEC 之间的相互相互作用，以及 IEL 与肠上皮外免疫细胞的通讯。我们在此回顾 IEL 在维持粘膜屏障完整性方面的前哨功能，以及失调的 IEL 反应如何导致病理学。