title: Tissue-resident memory T cells: local guards of the thymus.
abstract: T-cell surveillance of nonlymphoid tissues has traditionally been ascribed to recirculating memory T cells that continuously patrol the body. Extending this concept, recent evidence suggests that T cells also exist as nonmigratory memory cells that provide local immune protection in a broad range of peripheral tissues, including barrier locations such as skin and mucosa. In this issue of the European Journal of Immunology, Pircher and colleagues [Eur. J. Immunol. 2013. 43: 2295-2304] demonstrate, for the first time, the existence of such permanently tissue-resident CD8(+) memory T (TRM) cells in a primary lymphoid organ, the thymus. TRM cells in this location provide potent local immunity, which may help to preserve thymic integrity and normal T-cell development in the face of infection with thymus-invading pathogens.
authors.affiliation: Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Laura K
authors.initials: LK
authors.lastname: Mackay
authors.forename: Thomas
authors.initials: T
authors.lastname: Gebhardt
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D007156:Immunologic Memory; D008217:Lymphocytic choriomeningitis virus / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology*; D014616:Vaccinia virus / Q000276:immunology*
keywords: CD8+ T cells; Thymus; Tissue-resident cells