Estrogen is a negative regulator of lymphopoiesis and provides an experimental tool for probing relationships between lymphocyte precursors and stem cells. We found that expression of lymphocyte-associated genes and immunoglobulin (Ig) gene rearrangement occurred before CD45R acquisition. Lymphoid-restricted progenitors that were Lin-IL-7Rα+c-kitloTdT+ (lineage marker-, interleukin receptor 7α+, c-kitlo and terminal deoxynucleotidyl transferase+) were selectively depleted in estrogen-treated mice; within a less differentiated Lin-c-kithi fraction, functional precursors of B and T, but not myeloid, cells were also selectively depleted. TdT and an Ig heavy chain transgene were detected within a hormone-regulated Lin-c-kithiSca-I +CD27+Flk-2+IL-7Rα- subset of this multipotential progenitor population. Identification of these extremely early lymphoid precursors should facilitate investigation of the molecular mechanisms that control lineage-fate decisions in hematopoiesis.
ASJC Scopus subject areas
- Immunology and Allergy