title: Major T cell progenitor activity in bone marrow-derived spleen colonies.
abstract: Common lymphoid progenitors (CLP) are generated in adult bone marrow (BM), but the intermediate steps leading to T cell commitment are unknown, and so is the site at which this commitment occurs. Here, we show that colonies arising in the spleen 12 days after BM injection harbor T cell precursors that are undetectable in BM. These precursors did not generate myeloid cells in vivo but repopulated the thymus and the peripheral T cell compartment much faster than did CLP. Two lineage negative (Lin(-)) subpopulations were distinguished, namely CD44(+) Thy1(-) cells still capable of natural killer generation and transient low-level B cell generation, and T cell-restricted CD44(-) Thy1(+) cells. At a molecular level, frequency of CD3epsilon and preTalpha mRNA was very different in each subset. Furthermore, only the CD44(-) Thy1(+) subset have initiated rearrangements in the T cell receptor beta locus. Thus, this study identifies extramedullary T cell progenitors and will allow easy approach to T cell commitment studies.
authors.affiliation: INSERM U345, Institut Necker. CNRS UMR 8603, Hôpital Necker. IFR 94 (Institut Fédératif de Recherche Necker-Enfants-Malades), 75730 Paris Cedex 15, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Lancrin
authors.forename: Elke
authors.initials: E
authors.lastname: Schneider
authors.forename: Florence
authors.initials: F
authors.lastname: Lambolez
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Arcangeli
authors.forename: Corinne
authors.initials: C
authors.lastname: Garcia-Cordier
authors.forename: Benedita
authors.initials: B
authors.lastname: Rocha
authors.forename: Sophie
authors.initials: S
authors.lastname: Ezine
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000276:immunology*; D003114:Colony-Forming Units Assay; D017931:DNA Primers; D015329:Gene Rearrangement, T-Lymphocyte / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D017931:DNA Primers