In vitro assays misrepresent in vivo lineage potentials of murine lymphoid progenitors

Blood. 2011 Mar 3;117(9):2618-24. doi: 10.1182/blood-2010-05-287102. Epub 2010 Dec 16.


The identity of T-cell progenitors that seed the thymus has remained controversial, largely because many studies differ over whether these progenitors retain myeloid potential. Contradictory reports diverge in their use of various in vitro and in vivo assays. To consolidate these discordant findings, we compared the myeloid potential of 2 putative thymus seeding populations, common lymphoid progenitors (CLPs) and multipotent progenitors (MPPs), and the earliest intrathymic progenitor (DN1), using 2 in vitro assays and in vivo readouts. These assays gave contradictory results: CLP and DN1 displayed surprisingly robust myeloid potential on OP9-DL1 in vitro stromal cocultures but displayed little myeloid potential in vivo, as well as in methylcellulose cultures. MPP, on the other hand, displayed robust myeloid potential in all settings. We conclude that stromal cocultures reveal cryptic, but nonphysiologic, myeloid potentials of lymphoid progenitors, providing an explanation for contradictory findings in the field and underscoring the importance of using in vivo assays for the determination of physiologic lineage potentials.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Assay / methods*
  • Cell Differentiation / drug effects
  • Cell Lineage* / drug effects
  • Coculture Techniques
  • Lymphoid Progenitor Cells / cytology*
  • Lymphoid Progenitor Cells / drug effects
  • Methylcellulose / pharmacology
  • Mice
  • Multipotent Stem Cells / cytology
  • Multipotent Stem Cells / drug effects
  • Myeloid Cells / cytology
  • Myeloid Cells / drug effects
  • Stem Cell Transplantation
  • Stromal Cells / cytology
  • Stromal Cells / drug effects
  • Whole-Body Irradiation


  • Methylcellulose