Human CD34+ cell preparations contain over 100-fold greater NOD/SCID mouse engrafting capacity than do CD34- cell preparations.
OBJECTIVE
The CD34 cell surface marker is used widely for stem/progenitor cell isolation. Since several recent studies reported that CD34(-) cells also have in vivo engrafting capacity, we quantitatively compared the engraftment potential of CD34(+) vs CD34(-) cell preparations from normal human placental/umbilical cord blood (CB), bone marrow (BM), and mobilized peripheral blood (PBSC) specimens, using the nonobese diabetic/severe combined immunodeficient (NOD/SCID) mouse model.


METHODS
CD34(+) and CD34(-) cell preparations were purified by four different approaches in 14 individual experiments involving 293 transplanted NOD/SCID mice. In most experiments, CD34(+) cells were depleted twice (CD34(=)) in order to obtain efficient depletion of CD34(+) cells from the CD34(-) cell preparations.


RESULTS
Dose-dependent levels of human hematopoietic cells were observed after transplantation of CD34(+) cell preparations. To rigorously assess the complementary CD34(-) cell preparations, cell doses 10- to 1000-fold higher than the minimum dose of the CD34(+) cell preparations necessary for engraftment were transplanted. Nevertheless, of 125 NOD/SCID mice transplanted with CD34(-) cell preparations purified from the same starting cells, only six mice had detectable human hematopoiesis, by flow cytometric or PCR assay.


CONCLUSIONS
CD34(-) cells provide only a minor contribution to hematopoietic engraftment in this in vivo model system, as compared to CD34(+) cells from the same samples of noncultured human cells. Hematopoiesis derived from actual CD34(-) cells is difficult to distinguish from that due to CD34(+) cells potentially contaminating the preparations.
Gao
Z
Z
Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Fackler
M J
MJ
Leung
W
W
Lumkul
R
R
Ramirez
M
M
Theobald
N
N
Malech
H L
HL
Civin
C I
CI
D000818:Animals; D018952:Antigens, CD34 / Q000096:biosynthesis / Q000276:immunology*; D015415:Biomarkers; D006085:Graft Survival / Q000276:immunology*; D019650:Hematopoietic Stem Cell Mobilization; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D014184:Transplantation, Homologous
D018952:Antigens, CD34; D015415:Biomarkers