Major T cell progenitor activity in bone marrow-derived spleen colonies

J Exp Med. 2002 Apr 1;195(7):919-29. doi: 10.1084/jem.20011475.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bone Marrow Cells / immunology*
  • Colony-Forming Units Assay
  • DNA Primers
  • Gene Rearrangement, T-Lymphocyte / immunology*
  • Hematopoietic Stem Cells / immunology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Nude
  • Reverse Transcriptase Polymerase Chain Reaction
  • Spleen / immunology*
  • T-Lymphocytes / immunology*


  • DNA Primers