CD34 expression by murine hematopoietic stem cells. Developmental changes and kinetic alterations.
For more than a decade it was believed that hematopoietic stem cells express CD34. However, this dogma was recently challenged by the observation that stem cells of normal adult mice are CD34-. In order to clarify the controversy, we carried out systematic examination of stem cells by using C57BL/6 mice that are congenic for Ly-5. As reported previously, stem cells in the normal adult mice were CD34-. However, stem cells stimulated in vivo by 5-fluorouracil injection or in vitro by a combination of interleukin-11 and steel factor were CD34+. The activated CD34+ stem cells reverted to CD34- when the recipients' marrow achieved steady state. The majority of G-CSF-mobilized stem cells also were CD34+ and reverted to CD34- under steady-state conditions. Most recently, we examined the developmental changes of stem cell CD34 expression. In order to gain information on the total population of stem cells we prepared CD34+ and CD34- populations of mononuclear cells without prior enrichment and studied their engrafting potentials. All stem cells from perinatal to 5-week-old mice were CD34+. In 7-week-old mice CD34- stem cells began to emerge, and the majority of the stem cells were CD34- in the 10- and 20-week-old mice. An estimated 20% of the adult stem cells expressed CD34. These observations provide insight into the current controversy regarding CD34 expression by adult hematopoietic stem cells.
Ogawa
M
M
Departments of Medicine and Pediatrics, Medical University of South Carolina, USA. ogawam@musc.edu
Tajima
F
F
Ito
T
T
Sato
T
T
Laver
J H
JH
Deguchi
T
T
D000818:Animals; D020296:Animals, Congenic; D018952:Antigens, CD34 / Q000096:biosynthesis* / Q000235:genetics; D000950:Antigens, Ly / Q000235:genetics; D001854:Bone Marrow Cells / Q000737:chemistry; D002453:Cell Cycle; D005472:Fluorouracil / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D019650:Hematopoietic Stem Cell Mobilization; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006413:Hematopoietic System / Q000254:growth & development*; D017370:Interleukin-11 / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D011994:Recombinant Proteins / Q000494:pharmacology; D019089:Stem Cell Factor / Q000494:pharmacology
D018952:Antigens, CD34; D000950:Antigens, Ly; D017370:Interleukin-11; D011994:Recombinant Proteins; D019089:Stem Cell Factor; D016179:Granulocyte Colony-Stimulating Factor; D005472:Fluorouracil