Human FLT3 ligand acts on myeloid as well as multipotential progenitors derived from purified CD34+ blood progenitors expressing different levels of c-kit protein.
We studied the effect of human flt3/flk2 ligand (FL) on the proliferation and differentiation of purified CD34+ blood progenitors which express different levels of c-kit protein in clonal cell culture in comparison with that of stem cell factor (SCF). FL alone did not support significant colony formation. However, FL significantly enhanced neutrophil colony (CFU-G) formation in the presence of granulocyte-colony stimulating factor (G-CSF) by peripheral blood (PB)-derived CD34+c-kit- cells which contained a large number of CFU-G. In addition, FL could synergistically increase the number of CFU-G supported by a combination of interleukin (IL)-3 and G-CSF, as did SCF. As we reported previously, SCF showed a significant burst-promoting activity (BPA). In contrast, FL did not exhibit any BPA on PB-derived CD34+c-kithigh cells in which erythroid-burst (BFU-E) was highly enriched. However, FL could synergize with IL-3 or GM-CSF in support of erythrocyte-containing mixed (E-Mix) colony by PB-derived CD34+c-kithigh or low cells in the presence of Epo. Replating of E-Mix colonies derived from CD34+c-kithigh cells supported by IL-3+Epo+SCF yielded more secondary colonies than those supported by IL-3+Epo or IL-3+Epo+FL. When PB-derived CD34+c-kitlow cells which represent a more immature population than CD34+c-kithigh cells were used as the target, number of secondary colonies supported by IL-3+Epo, IL-3+Epo+SCF or IL-3+Epo+FL was comparable. However, the number of lineages expressed in the secondary culture was significantly larger in the primary culture containing IL-3+Epo+FL than in that containing IL-3+Epo. These results suggest that FL not only acts on neutrophilic progenitors, but also on more immature multipotential progenitors.
Sonoda
Y
Y
Department of Hygiene, Kyoto Prefectural University of Medicine, Japan.
Kimura
T
T
Sakabe
H
H
Tanimukai
S
S
Ohmizono
Y
Y
Nakagawa
S
S
Yokota
S
S
Lyman
S D
SD
Abe
T
T
D015703:Antigens, CD / Q000097:blood; D018952:Antigens, CD34 / Q000097:blood*; D001854:Bone Marrow Cells; D002999:Clone Cells; D003114:Colony-Forming Units Assay; D004305:Dose-Response Relationship, Drug; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D008565:Membrane Proteins / Q000494:pharmacology*; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects; D011994:Recombinant Proteins / Q000494:pharmacology; D018709:Statistics, Nonparametric
D015703:Antigens, CD; D018952:Antigens, CD34; D007377:Interleukin-3; D008565:Membrane Proteins; D011994:Recombinant Proteins; C084881:flt3 ligand protein; D016179:Granulocyte Colony-Stimulating Factor