Haematopoietic action of flt3 ligand on cord blood-derived CD34-positive cells expressing different levels of flt3 or c-kit tyrosine kinase receptor: comparison with stem cell factor.
We compared the effect of human flt3 ligand (FL) and stem cell factor (SCF) on cord blood (CB)-derived CD34+ cells expressing different levels of flt3 or c-kit tyrosine kinase (TK) receptor in clonal cell culture. The c-kit receptor was expressed by 58.5+/-16.7% of CB CD34+ cells (n=19), in which c-kit(high), c-kit(low) and c-kit cell populations could be identified. In contrast, the flt3 receptor (FR) was weakly expressed on 58.6+/-8.3% (n=9) of CB CD34+ cells. FL+erythropoietin (Epo) failed to support erythroid burst (BFU-E) formation by any subpopulation of CD34+ cells. However, SCF + Epo supported BFU-E and erythrocyte-containing mixed (CFU-mix) colony formation from all subpopulations. Interestingly, FL markedly augmented CFU-mix colony formation supported by interleukin (IL)-3 + Epo when CD34+c-kit(low) or CD34+FR+ cells were used as the target. On the other hand, SCF significantly enhanced CFU-mix colony formation supported by IL-3 + Epo when CD34+c-kit(high) or low and CD34+FR+ cells were used. The replating potential of CFU-mix supported by IL-3 + Epo+ FL was greater when CD34+c-kit(low) or CD34+FR+ cells were used. When the CD34+c-kit(low) cells were used, the number of lineages expressed in secondary cultures of CFU-mix colonies derived from primary cultures containing IL-3 + Epo + FL or SCF was significantly larger than when the primary cultures contained IL-3 + Epo. Furthermore, the number of long-term culture-initiating cells found in CD34+FR+ cells was larger than that in FR cells. CB-derived CD34+c-kit(low) cells represent a less mature population than c-kit(high) cells, as reported previously. Therefore, these results indicate that both FL and SCF can act on primitive multipotential progenitors. However, it is still uncertain whether CB-derived CD34+FR+ cells are less mature than CD34+FR- cells.
Sakabe
H
H
Department of Hygiene, Kyoto Prefectural University of Medicine, Japan.
Kimura
T
T
Zeng
Z
Z
Minamiguchi
H
H
Tsuda
S
S
Yokota
S
S
Hodohara
K
K
Abe
T
T
Lyman
S D
SD
Sonoda
Y
Y
D018952:Antigens, CD34 / Q000032:analysis*; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D016895:Culture Media, Serum-Free; D015672:Erythroid Precursor Cells / Q000166:cytology / Q000378:metabolism; D004921:Erythropoietin / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry; D006410:Hematopoiesis / Q000187:drug effects*; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism / Q000494:pharmacology*; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism*; D019089:Stem Cell Factor / Q000494:pharmacology*
D018952:Antigens, CD34; D016895:Culture Media, Serum-Free; D007377:Interleukin-3; D008565:Membrane Proteins; D019089:Stem Cell Factor; C084881:flt3 ligand protein; D004921:Erythropoietin; D019009:Proto-Oncogene Proteins c-kit