title: Molecular signature of recent thymic selection events on effector and regulatory CD4+ T lymphocytes.
abstract: Natural CD4+CD25+ regulatory T lymphocytes (Treg) are key protagonists in the induction and maintenance of peripheral T cell tolerance. Their thymic origin and biased repertoire continue to raise important questions about the signals that mediate their development. We validated analysis of MHC class II capture by developing thymocytes from thymic stroma as a tool to study quantitative and qualitative aspects of the cellular interactions involved in thymic T cell development and used it to analyze Treg differentiation in wild-type mice. Our data indicate that APCs of bone marrow origin, but, surprisingly and importantly, not thymic epithelial cells, induce significant negative selection among the very autoreactive Treg precursors. This fundamental difference between thymic development of regulatory and effector T lymphocytes leads to the development of a Treg repertoire enriched in cells specific for a selected subpopulation of self-Ags, i.e., those specifically expressed by thymic epithelial cells.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, Unité 563, Centre de Physiopathologie Toulouse Purpan, Toulouse, France. paola.romagnoli@toulouse.inserm.fr
authors.forename: Paola
authors.initials: P
authors.lastname: Romagnoli
authors.forename: Denis
authors.initials: D
authors.lastname: Hudrisier
authors.forename: Joost P M
authors.initials: JP
authors.lastname: van Meerwijk
mesh_terms: D000818:Animals; D002450:Cell Communication; D006410:Hematopoiesis; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D015375:Receptors, Interleukin-2 / Q000032:analysis; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000502:physiology*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*
chemical_list: D000949:Histocompatibility Antigens Class II; D015375:Receptors, Interleukin-2