Tissue-Resident Memory T Cell: Ontogenetic Cellular Mechanism and Clinical Translation

Abstract Mounting evidence has indicated the essential role of tissue-resident memory T (TRM) cells for frontline protection against viral infection and for cancer immune surveillance (Mueller SN, Mackay LK. Tissue-resident memory T cells: local specialists in immune defense. Nat Rev Immunol 2016, 16, 79–89. doi:10.1038/nri.2015.3.). TRM cells are transcriptionally, phenotypically, and functionally distinct from circulating memory T (Tcirm) cells. It is necessary to understand the unique ontogenetic mechanism, migratory regulation, and biological function of TRM cells. In this review, we discuss recent insights into cellular mechanisms and discrete responsiveness in different tissue microenvironments underlying TRM cell development. We also emphasize the translational potential of TRM cells by focusing on their establishment in association with improved protection in mucosal tissues against various types of diseases and effective strategies for eliciting TRM cells in both pre-clinical and clinical studies.