Differential cytokine effects on primitive (CD34+CD38-) human hematopoietic cells: novel responses to Flt3-ligand and thrombopoietin

J Exp Med. 1996 Jun 1;183(6):2551-8. doi: 10.1084/jem.183.6.2551.


A high proportion of the CD34+CD38- cells in normal human marrow are defined as long-term culture-initiating cells (LTC-IC) because they can proliferate and differentiate when co-cultured with cytokine-producing stromal feeder layers. In contrast, very few CD34+CD38- cells will divide in cytokine-containing methylcellulose and thus are not classifiable as direct colony-forming cells (CFC), although most can proliferate in serum-free liquid cultures containing certain soluble cytokines. Analysis of the effects of 16 cytokines on CD34+CD38- cells in the latter type of culture showed that Flt3-ligand (FL), Steel factor (SF), and interleukin (IL)-3 were both necessary and sufficient to obtain an approximately 30-fold amplification of the input LTC-IC population within 10 d. As single factors, only FL and thrombopoietin (TPO) stimulated a net increase in LTC-IC within 10 d. Interestingly, a significantly increased proportion of the CFC produced from the TPO-amplified LTC-IC were erythroid. Increases in the number of directly detectable CFC of > 500-fold were also obtainable within 10 d in serum-free cultures of CD34+CD38- cells. However, this required the presence of IL-6 and/or granulocyte/colony-stimulating factor and/or nerve growth factor beta in addition to FL, SF, and IL-3. Also, for this response, the most potent single-acting factor tested was IL-3, not FL. Identification of cytokine combinations that differentially stimulate primitive human hematopoietic cell self-renewal and lineage determination should facilitate analysis of the intracellular pathways that regulate these decisions as well as the development of improved ex vivo expansion and gene transfer protocols.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADP-ribosyl Cyclase
  • ADP-ribosyl Cyclase 1
  • Antigens, CD*
  • Antigens, CD34 / immunology*
  • Antigens, Differentiation / immunology*
  • Bone Marrow Cells
  • Cell Division
  • Cells, Cultured
  • Colony-Forming Units Assay
  • Cytokines / pharmacology*
  • Hematopoiesis
  • Hematopoietic Stem Cells / drug effects
  • Hematopoietic Stem Cells / immunology*
  • Humans
  • Interleukin-3 / pharmacology
  • Kinetics
  • Lymphocyte Activation
  • Lymphocytes / drug effects
  • Lymphocytes / immunology*
  • Membrane Glycoproteins
  • Membrane Proteins / pharmacology*
  • N-Glycosyl Hydrolases / immunology*
  • Stem Cell Factor / pharmacology
  • Thrombopoietin / pharmacology*


  • Antigens, CD
  • Antigens, CD34
  • Antigens, Differentiation
  • Cytokines
  • Interleukin-3
  • Membrane Glycoproteins
  • Membrane Proteins
  • Stem Cell Factor
  • flt3 ligand protein
  • Thrombopoietin
  • N-Glycosyl Hydrolases
  • ADP-ribosyl Cyclase
  • CD38 protein, human
  • ADP-ribosyl Cyclase 1