Functional and kinetic characterization of granulocyte colony-stimulating factor-primed CD34- human stem cells

Roberto M. Lemoli, Francesco Bertolini, Maria T. Petrucci, Chiara Gregorj, Maria R. Ricciardi, Miram Fogli, Antonio Curti, Cristina Rabascio, Simona Pandolfi, Sergio Ferrari, Robin Fo, Michele Baccarani, Agostino Tafuri

Research output: Contribution to journalArticlepeer-review


We assessed the functional properties and the kinetic status in vitro, and the engraftment potential in vivo of human haematopoietic stem cells according to the expression of CD34 antigen. Lin-CD34- and Lin -CD34+ cells were isolated from granulocyte colony-stimulating factor-primed peripheral blood (PB) cells of healthy donors. The CD34- cell fraction did not contain either clonogenic cells in semisolid culture or long-term culture initiating cells (LTC-IC). However, stroma-dependent liquid cultures and cytokines induced CD34 expression on a minority of stem cells, acquisition of clonogenic capacity and generation of LTC-IC. Significantly higher percentages of quiescent G0 cells and lower percentages of cycling G1 cells were found in Lin -CD34- cells when compared with Lin-CD34 + cells. Kinetic quiescence of Lin-CD34- cells was associated with a significantly higher expression of the negative regulators of the cell cycle, p27Kip1 and p21cip1/waf1. Cytokine-mediated induction of CD34, in vitro, resulted in cycling of stem cells and downregulation of p27. There was a higher rate of human long-term engraftment in immunocompromised non-obese diabetic (NOD)/recombination activating gene 1null and NOD/severe combined immunodeficient- β2microglobulinnull mice injected with CD34 + cells. Thus, our study indicated that CD34 expression on human PB stem cells was associated with haematopoietic activity, cell-cycle recruitment and downregulation of p27Kip1 in vitro and higher engraftment capacity in vivo.

Original languageEnglish
Pages (from-to)720-729
Number of pages10
JournalBritish Journal of Haematology
Issue number4
Publication statusPublished - Nov 2003


  • CD34
  • Cell cycle
  • Haematopoietic stem cells

ASJC Scopus subject areas

  • Hematology


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