Bone Marrow-Derived Cells Contribute to the Maintenance of Thymic Stroma including TECs.

In paradox to critical functions for T-cell selection and self-tolerance, the thymus undergoes profound age-associated atrophy and loss of T-cell function, further enhanced by cancer therapies. Identifying thymic epithelial progenitor populations capable of forming functional thymic tissue will be critical in understanding thymic epithelial cell (TEC) ontogeny and designing strategies to reverse involution. We identified a new population of progenitor cells, present in both the thymus and bone marrow (BM) of mice, that coexpress the hematopoietic marker CD45 and the definitive thymic epithelial marker EpCAM and maintain the capacity to form functional thymic tissue.