美国明尼苏达大学医学院David Masopust研究团队探明发育可塑性允许驻留记忆T（TRM）细胞可进行由外向内的免疫反应。相关论文发表在2020年2月17日出版的《自然-免疫学》杂志上。

他们观察到重新激活的TRM细胞重新进入循环池。表观遗传学分析表明，TRM细胞与常规记忆T细胞群体紧密匹配，与最近激活的效应子几乎没有相似之处。从小肠上皮分离的完全分化的TRM细胞在召回时表现出分化为中央记忆T（TCM）细胞、效应记忆T细胞和TRM细胞的潜力。

Ex-TRM细胞是重新进入循环池的前肠道TRM细胞，在随后的重新激活过程中可遗传地保持归巢，回到其原始组织，并增强再分化为TRM细胞的能力。因此，Ex-TRM细胞可以重新进入循环，但是在被调用时具有重新形成局部TRM的优势。

研究人员表示，TCM细胞巡逻淋巴结，并在应答再刺激时表现出常规的记忆反应：增殖、迁移和分化成各种T细胞亚群，同时还能自我更新。TRM细胞停留在单个器官内，与末端效应子特性相同，并有助于快速保护宿主。

附：英文原文

Title: Developmental plasticity allows outside-in immune responses by resident memory T cells

Author: Raissa Fonseca, Lalit K. Beura, Clare F. Quarnstrom, Hazem E. Ghoneim, Yiping Fan, Caitlin C. Zebley, Milcah C. Scott, Nancy J. Fares-Frederickson, Sathi Wijeyesinghe, Emily A. Thompson, Henrique Borges da Silva, Vaiva Vezys, Benjamin Youngblood, David Masopust

Issue&Volume: 2020-02-17

Abstract: Central memory T (TCM) cells patrol lymph nodes and perform conventional memory responses on restimulation: proliferation, migration and differentiation into diverse T cell subsets while also self-renewing. Resident memory T (TRM) cells are parked within single organs, share properties with terminal effectors and contribute to rapid host protection. We observed that reactivated TRM cells rejoined the circulating pool. Epigenetic analyses revealed that TRM cells align closely with conventional memory T cell populations, bearing little resemblance to recently activated effectors. Fully differentiated TRM cells isolated from small intestine epithelium exhibited the potential to differentiate into TCM cells, effector memory T cells and TRM cells on recall. Ex-TRM cells, former intestinal TRM cells that rejoined the circulating pool, heritably maintained a predilection for homing back to their tissue of origin on subsequent reactivation and a heightened capacity to redifferentiate into TRM cells. Thus, TRM cells can rejoin the circulation but are advantaged to re-form local TRM when called on.

DOI: 10.1038/s41590-020-0607-7

Source: https://www.nature.com/articles/s41590-020-0607-7