title: Distinct roles of the interleukin-7 receptor alpha chain in fetal and adult thymocyte development revealed by analysis of interleukin-7 receptor alpha-deficient mice.
abstract: Mouse mutants lacking expression of the IL-7 receptor (IL-7R) alpha chain are defective in thymopoiesis. The adult thymus has multiple defects, including reduced cell numbers and proportions of the more mature thymocyte subsets, a complete absence of CD25+ cells and a reduced level of RAG1 and RAG2 expression. We show here that, in contrast to the profound developmental arrest observed in the adult thymus, fetal thymocytes from IL-7Ralpha-/- mice have normal proportions of all of the major thymocyte subpopulations, including CD25+ thymocytes and the most mature single-positive subsets. Moreover, normal levels of RAG1 and RAG2 were observed. Total thymocyte numbers, however, remained reduced. These data suggest that the IL-7Ralpha chain is a key regulator of both survival and proliferation during thymocyte development but that it is not essential for the production of T cells during fetal thymopoiesis.
authors.affiliation: Department of Biology, Imperial College of Science, Technology and Medicine, London, GB. t.crompton@ic.ac.uk
authors.forename: T
authors.initials: T
authors.lastname: Crompton
authors.forename: S V
authors.initials: SV
authors.lastname: Outram
authors.forename: J
authors.initials: J
authors.lastname: Buckland
authors.forename: M J
authors.initials: MJ
authors.lastname: Owen
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology*; D002454:Cell Differentiation; D051379:Mice; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology; D018123:Receptors, Interleukin / Q000235:genetics / Q000276:immunology*; D020395:Receptors, Interleukin-7; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D016692:Receptors, Antigen, T-Cell, gamma-delta; D018123:Receptors, Interleukin; D020395:Receptors, Interleukin-7