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Updated: Jun 28, 2026

Characterization of Thymic Settling Progenitors in the Mouse Embryo Using In Vivo and In Vitro Assays
Published on: June 9, 2015
Reductive isolation from bone marrow and blood implicates common lymphoid progenitors as the major source of
Thomas Serwold1, L I R Ehrlich, Irving L Weissman
1Stanford Institute of Stem Cell Biology and Regenerative Medicine, CA, USA.
Abstract:
Ongoing thymopoiesis requires continual seeding from progenitors that reside within the bone marrow (BM), but the identity of the most proximate prethymocytes has remained controversial. Here we take a comprehensive approach to prospectively identify the major source of thymocyte progenitors that reside within the BM and blood, and find that all thymocyte progenitor activity resides within a rare Flk2(+)CD27(+) population. The BM Flk2(+)CD27(+) subset is predominantly composed of common lymphoid progenitors (CLPs) and multipotent progenitors. Of these 2 populations, only CLPs reconstitute thymopoiesis rapidly after intravenous injection. In contrast, multipotent progenitor-derived cells reconstitute the thymus with delayed kinetics only after they have reseeded the BM, self-renewed, and generated CLPs. These results identify CLPs as the major source of thymocyte progenitors within the BM.
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