Tissue Resident Memory Cells

Tissue resident memory T cells (TRM) are a relatively newly discovered subset of memory T cells. Rather than inhabiting secondary lymphoid tissue, they are lodged in peripheral tissues. While TRM can appear in any tissue, they are most abundant in tissues that abut the environment--skin, lung, gut, oral and vaginal mucosa. They accumulate as a result of T cell mediated inflammatory processes which occur in response to infection or encounter with a non-pathogenic antigen. Strategically, they can respond almost immediately to a subsequent encounter with the antigen for which they are specific, and thus play a critical role in host defense. CD8 TRM specific for pathogenic viruses have been described, as well as CD4 TRM for pathogenic fungi and other microorganisms. While TRM play a role in host defense, inappropriate activation of TRM in response to autoantigen or otherwise innocuous antigen is thought to play a key role in several T cell mediated inflammatory diseases, including psoriasis, spondyloarthritides, multiple sclerosis, type I diabetes, and asthma. Dislodging pathogenic TRM from tissue has proven difficult or impossible, and thus many of these disorders are relapsing even if successfully treated. Their dependence on cytokines such as IL-15, fatty acid metabolism, and expression of CD69 may represent targets of therapeutic opportunity.DisclosuresNo relevant conflicts of interest to declare.
Source: Blood - Category: Hematology Authors: Tags: The Making of Memory Source Type: research