title: Homeostatic signals do not drive post-thymic T cell maturation.
abstract: Recent thymic emigrants, the youngest T cells in the lymphoid periphery, undergo a 3 week-long period of functional and phenotypic maturation before being incorporated into the pool of mature, naïve T cells. Previous studies indicate that this maturation requires T cell exit from the thymus and access to secondary lymphoid organs, but is MHC-independent. We now show that post-thymic T cell maturation is independent of homeostatic and costimulatory pathways, requiring neither signals delivered by IL-7 nor CD80/86. Furthermore, while CCR7/CCL19,21-regulated homing of recent thymic emigrants to the T cell zones within the secondary lymphoid organs is not required for post-thymic T cell maturation, an intact dendritic cell compartment modulates this process. It is thus clear that, unlike T cell development and homeostasis, post-thymic maturation is focused not on interrogating the T cell receptor or the cell's responsiveness to homeostatic or costimulatory signals, but on some as yet unrecognized property.
authors.affiliation: Department of Immunology, University of Washington, WA 98195, United States.
authors.forename: Evan G
authors.initials: EG
authors.lastname: Houston
authors.forename: Tamar E
authors.initials: TE
authors.lastname: Boursalian
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Fink
mesh_terms: D000818:Animals; D018122:B7-1 Antigen / Q000378:metabolism; D051940:B7-2 Antigen / Q000378:metabolism; D054415:Chemokine CCL19 / Q000378:metabolism; D054421:Chemokine CCL21 / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism*; D006706:Homeostasis; D015851:Interleukin-7 / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D054400:Receptors, CCR7 / Q000378:metabolism; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D013950:Thymus Gland / Q000276:immunology
chemical_list: D018122:B7-1 Antigen; D051940:B7-2 Antigen; C515461:Ccl19 protein, mouse; C515371:Ccr7 protein, mouse; D054415:Chemokine CCL19; D054421:Chemokine CCL21; D015851:Interleukin-7; D054400:Receptors, CCR7