Characterization of c-kit expression by primitive hematopoietic progenitors in umbilical cord blood.
Human umbilical cord blood (CB) appears to be an exciting new source of transplantable stem cells for a variety of clinical conditions. In this study, we have attempted to further characterize the primitive progenitors in CB. First we analyzed the effects of early-acting growth factors on blast cell colony formation from CD34+ progenitors. Addition of Steel factor (SF), interleukin-6 (IL-6), or granulocyte colony-stimulating factor (G-CSF) to cultures containing interleukin-3 enhanced blast cell colony formation. These results indicated that cell cycle-dormant progenitors are present in CB. Next, based on results obtained in the murine system, we tested whether c-kit expression could separate the CB progenitors into cycle-dormant vs. cycle-active progenitors. Cells were separated into CD34+ c-kit-, c-kitlow, and c-kithigh. The results suggested that the c-kitlow population contains the majority of cycle-dormant progenitors and the c-kithigh population contains most of the forming cells were in the c-kitlow population, while the opposite is true for other colony-forming cells. Expression of c-kit may be useful in identifying CB progenitors with long-term engraftment capability.
Department of Pediatrics, Medical University of South Carolina, Charleston 29425, USA.
J H
JH
Laver
M R
MR
Abboud
I
I
Kawashima
A G
AG
Leary
L K
LK
Ashman
M
M
Ogawa
D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis; D002469:Cell Separation; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D005312:Fetal Blood / Q000166:cytology*; D015870:Gene Expression; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D015850:Interleukin-6 / Q000494:pharmacology; D051379:Mice; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D011994:Recombinant Proteins / Q000494:pharmacology; D019089:Stem Cell Factor / Q000494:pharmacology
D018952:Antigens, CD34; D007377:Interleukin-3; D015850:Interleukin-6; D011994:Recombinant Proteins; D019089:Stem Cell Factor; D016179:Granulocyte Colony-Stimulating Factor; D019009:Proto-Oncogene Proteins c-kit