title: The ontogeny of B cells in the thymus of normal, CD3 epsilon knockout (KO), RAG-2 KO and IL-7 transgenic mice.
abstract: The ontogeny of thymic B cells was determined by three-color flow cytometry and the presence or absence of B cell progenitors confirmed by cell culture experiments. In the thymus of young normal mice, CD117(+), B220(low) pro- and pre-B cells are present but disappear with age. B220(low), CD5(+), B-1 B cells are present in the thymus of older animals following the appearance of similar cells in the peritoneal cavity and blood. In CD3 epsilon gene-deleted mice, the phenotypic progression and number of thymic B cells remains unaltered, showing that blocking T cell development does not automatically result in an increase of thymic B lymphopoiesis. Pro-B cells in RAG-2 knockout mice are found in the fetal and neonatal blood, spleen and thymus, but with increasing age are only found in the bone marrow. B lymphopoiesis in adult IL-7 transgenic mice is dramatically altered with CD117(+) pro- and pre-B cells present in spleen, lymph node and blood. In the thymus of adult IL-7 transgenic mice, the fraction of CD117(+) thymic B cells is significantly increased. These results show that in the steady state, the phenotype of thymic B cells is critically dependent on both mouse age and the phenotype of circulating B cells.
authors.affiliation: Laboratoire d'Immunochimie, U548 INSERM, Commissariat à l'Energie Atomique-Grenoble, Département de Biologie Moléculaire et Structurale, Université Joseph Fourier, 17 rue des Martyrs, 38054 Grenoble, France. ceredig@dsvsud.cea.fr
authors.forename: Rhodri
authors.initials: R
authors.lastname: Ceredig
mesh_terms: D000367:Age Factors; D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D002478:Cells, Cultured; D004268:DNA-Binding Proteins; D005434:Flow Cytometry; D018960:Hyaluronan Receptors / Q000032:analysis; D015851:Interleukin-7 / Q000502:physiology; D017493:Leukocyte Common Antigens / Q000032:analysis; D016131:Lymphocyte Subsets / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D013950:Thymus Gland / Q000276:immunology / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; D018960:Hyaluronan Receptors; D015851:Interleukin-7; C499308:Rag2 protein, mouse; C064655:V(D)J recombination activating protein 2; D017493:Leukocyte Common Antigens