Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Switzerland.
Eur J Immunol. 2019 Jun;49(6):849-852. doi: 10.1002/eji.201948208.
Following infection, tissue-resident memory T cells (Trm) are thought to be left behind at sites of antigen encounter to protect affected tissues against subsequent reinfection. In this issue of the European Journal of Immunology, however, Pascutti et al. demonstrate that both murine and human CD8 Trm specific to seven different pathogens, including systemic, skin, and lung tissue-localized pathogens, accumulate in the bone marrow (BM). These cells have a CD69 phenotype, develop independently of local antigen, and require IL-15, Blimp-1, and Hobit for their differentiation and maintenance. Following restimulation, these cells expand and rapidly produce cytokines. While some of these responses may protect the BM from infection, the consideration that some of these pathogens or their antigens might never reach the BM suggests additional functional roles of BM Trm, possibly in supporting hematopoietic functions via cytokine production following infection. It will be further interesting to determine whether BM Trm contribute to the circulating effector pool following reinfection with tissue-localized or systemic pathogens and whether these cells can be elicited by vaccination.
感染后，组织驻留记忆 T 细胞（Trm）被认为会留在抗原接触的部位，以保护受感染的组织免受随后的再次感染。然而，在本期《欧洲免疫学杂志》上，Pascutti 等人证明，针对包括全身性、皮肤和肺部组织定位病原体在内的七种不同病原体的小鼠和人类 CD8 Trm 都会在骨髓（BM）中积累。这些细胞具有 CD69 表型，独立于局部抗原发育，并且其分化和维持需要 IL-15、Blimp-1 和 Hobit。再刺激后，这些细胞会扩增并迅速产生细胞因子。虽然这些反应中的一些可能会保护 BM 免受感染，但考虑到这些病原体或其抗原中的一些可能从未到达 BM，这表明 BM Trm 具有其他功能作用，可能通过感染后产生细胞因子来支持造血功能。进一步有趣的是，确定 BM Trm 是否会在再次感染组织定位或全身性病原体后有助于循环效应物池的形成，以及这些细胞是否可以通过疫苗接种来诱导。
