title: Phenotypic plasticity of T cell progenitors upon exposure to Notch ligands.
abstract: Despite many efforts, the nature of thymic immigrants that give rise to T cells has remained obscure, especially since it became known that extrathymic lineage-negative, Sca-1-positive, c-kit high progenitor cells differ from intrathymic early T cell progenitors (ETPs) by functional potential and dependence on Notch signaling. After our observation that intrathymic T cell precursors expressing a human CD25 reporter under control of pre-TCRalpha regulatory elements almost exclusively have the ETP phenotype, we have analyzed the phenotypic changes of reporter-expressing common lymphoid progenitor (CLP) cells in the bone marrow when cultured on Delta-like 1-expressing stromal cells. We note that these quickly adopt the phenotype of double negative (DN)2 thymocytes with little display of the ETP phenotype. Our data suggest that common lymphoid progenitor (CLP) cells could be responsible for the rapid reconstitution of thymus function after bone marrow transplantation since CLP cells in the blood have the capacity to rapidly enter the thymus and become DN2 thymocytes.
authors.affiliation: Harvard Medical School, Dana-Farber Cancer Institute, Boston, MA 02115, USA. Andreas_Krueger@dfci.harvard.edu
authors.forename: Andreas
authors.initials: A
authors.lastname: Krueger
authors.forename: Annette I
authors.initials: AI
authors.lastname: Garbe
authors.forename: Harald
authors.initials: H
authors.lastname: von Boehmer
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D006801:Humans; D008024:Ligands; D051379:Mice; D008822:Mice, Transgenic; D010641:Phenotype; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D051880:Receptors, Notch / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D051941:fms-Like Tyrosine Kinase 3 / Q000378:metabolism
chemical_list: D008024:Ligands; D015375:Receptors, Interleukin-2; D051880:Receptors, Notch; C497971:Flt3 protein, mouse; D051941:fms-Like Tyrosine Kinase 3