title: Recirculating memory T cells are a unique subset of CD4+ T cells with a distinct phenotype and migratory pattern.
abstract: Several populations of memory T cells have been described that differ in their migration and function. In this study, we have identified a unique subset of memory T cells, which we have named recirculating memory T cells (T(RCM)). By exposing Kaede transgenic mouse skin to violet light, we tracked the fate of cutaneous T cells. One population of memory CD4(+) T cells remained in the skin. A second population migrated from the skin into draining lymph nodes (LNs) in a CCR7-dependent manner. These migrating CD4(+) T cells expressed a novel cell surface phenotype (CCR7(int/+)CD62L(int)CD69(-)CD103(+/-) E-selectin ligands(+)) that is distinct from memory T cell subsets described to date. Unlike memory T cell subsets that remain resident within tissues long-term, or that migrate either exclusively between lymphoid tissues or into peripheral nonlymphoid sites, CD4(+) T(RCM) migrate from the skin into draining LNs. From the draining LNs, CD4(+) T(RCM) reenter into the circulation, distal LNs, and sites of non-specific cutaneous inflammation. In addition, CD4(+) T(RCM) upregulated CD40L and secreted IL-2 following polyclonal stimulation. Our results identify a novel subset of recirculating memory CD4(+) T cells equipped to deliver help to both distal lymphoid and cutaneous tissues.
authors.affiliation: Division of Rheumatology, Allergy and Immunology, Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Shannon K
authors.initials: SK
authors.lastname: Bromley
authors.forename: Sha
authors.initials: S
authors.lastname: Yan
authors.forename: Michio
authors.initials: M
authors.lastname: Tomura
authors.forename: Osami
authors.initials: O
authors.lastname: Kanagawa
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Luster
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D023201:CD40 Ligand / Q000096:biosynthesis; D019070:Cell Lineage; D002465:Cell Movement; D007156:Immunologic Memory; D016130:Immunophenotyping; D007376:Interleukin-2 / Q000378:metabolism; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics / Q000528:radiation effects; D008198:Lymph Nodes / Q000276:immunology / Q000473:pathology; D008221:Lymphoid Tissue / Q000276:immunology / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D011828:Radiation Chimera; D054400:Receptors, CCR7 / Q000172:deficiency / Q000276:immunology; D016201:Receptors, Lymphocyte Homing / Q000276:immunology; D012867:Skin / Q000276:immunology / Q000528:radiation effects; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D015703:Antigens, CD; C515371:Ccr7 protein, mouse; D007376:Interleukin-2; C513582:Kaede protein, Trachyphyllia geoffroyi; D008164:Luminescent Proteins; D054400:Receptors, CCR7; D016201:Receptors, Lymphocyte Homing; D023201:CD40 Ligand