The FLT3 ligand is a direct and potent stimulator of the growth of primitive and committed human CD34+ bone marrow progenitor cells in vitro

Blood. 1996 Feb 15;87(4):1317-25.


The present studies investigated the effects of the recently cloned flt3 ligand (FL) on the in vitro growth and differentiation of primitive and committed subsets of human CD34+ bone marrow (BM) progenitor cells. FL alone was a weak growth stimulator of CD34+ BM cells, but synergistically and directly enhanced colony formation in combination with interleukin (IL) 3, granulocyte colony-stimulating factor (G-CSF), CSF-1, granulocyte macrophage (GM) CSF stem cell factor (SCF), and IL-6. FL and SCF were equally effective in stimulating colony formation in combination with IL-3. However, the tri-factor combination of FL + IL-3 + SCF stimulated 2.3-fold and 2.5-fold more colonies than FL + IL-3 and SCF + IL-3, respectively. These additional recruited progenitors appeared to be predominantly located in a primitive (CD71-) subset of the CD34+ progenitors, as 4.5-fold more colonies were formed by CD34+CD71- cells in response to FL + IL-3 + SCF than to FL + IL-3 or SCF + IL-3. Similar findings were observed in serum-containing and serum-deprived cultures. Whereas FL did not enhance burst-forming unit-erythroid (BFU-E) colony formation of CD34+ BM cells in the presence of serum, a low number of BFU-E colonies were formed in response to FL plus erythropoietin (Epo) under serum-deprived conditions. In addition, FL both in serum-containing and serum-deprived cultures stimulated colony formation of more committed myeloid progenitors in CD34+CD71+ BM cells. Thus, FL potently stimulates the growth of primitive and more committed human BM progenitor cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antigens, CD / analysis
  • Antigens, CD34 / analysis
  • Antigens, Differentiation, B-Lymphocyte / analysis
  • Bone Marrow Cells*
  • Cell Differentiation / drug effects
  • Cell Division
  • Cells, Cultured
  • Growth Substances / physiology
  • Hematopoiesis*
  • Hematopoietic Stem Cells / cytology*
  • Humans
  • Interleukin-3 / pharmacology
  • Membrane Proteins / chemistry
  • Membrane Proteins / physiology*
  • Receptors, Transferrin
  • Stem Cell Factor / physiology


  • Antigens, CD
  • Antigens, CD34
  • Antigens, Differentiation, B-Lymphocyte
  • CD71 antigen
  • Growth Substances
  • Interleukin-3
  • Membrane Proteins
  • Receptors, Transferrin
  • Stem Cell Factor
  • flt3 ligand protein