Coculture and transplant of purified CD34(+)Lin(-) and CD34(-)Lin(-) cells reveals functional interaction between repopulating hematopoietic stem cells.
The human hematopoietic stem cell compartment is comprised of repopulating CD34(+) and CD34(-) cells. The interaction between these subsets with respect to their reconstitution capacity in vivo remains to be characterized. Here, lineage-depleted (Lin(-)) human CD34(+) and CD34(-) hematopoietic cells were isolated from human male and female umbilical cord blood (CB) and transplanted into immune-deficient NOD/SCID EMV(null) mice, thereby allowing the use of human and Y-chromosome-specific DNA sequences to discriminate human reconstitution contributed by CD34(+) vs CD34(-) repopulating stem cells. Although cultured human CB CD34(-)Lin(-) cells transplanted alone possessed only minimal repopulating capacity, with 15% of mice achieving low levels of engraftment, transplantation of cocultured male CD34(-)Lin(-) cells with female CD34(+)Lin(-) cells demonstrated human repopulation with a contribution from CD34(-)Lin(-)-derived progeny in 80% of the recipients. After coculture and transplantation, male CD34(-)Lin(-) cells gave rise to primitive CD34(+)CD38(-) cells isolated in vivo, which demonstrated clonogenic progenitor function into multiple lineages. Taken together, our study indicates that the presence of CD34(+)Lin(-) cells in coculture enhanced the low repopulating function of human CD34(-)Lin(-) cells in vivo. We propose that CD34(+)Lin and CD34(-)Lin cells represent phenotypically distinct, but related cell types that exhibit unique and previously unappreciated functional interaction.
Hess
D A
DA
Robarts Research Institute, Stem Cell Biology and Regenerative Medicine, 100 Perth Drive, London, Ontario, Canada.
Karanu
F N
FN
Levac
K
K
Gallacher
L
L
Bhatia
M
M
D000818:Animals; D018952:Antigens, CD34; D001854:Bone Marrow Cells / Q000166:cytology; D002450:Cell Communication; D019070:Cell Lineage; D002469:Cell Separation; D018920:Coculture Techniques; D005260:Female; D005312:Fetal Blood / Q000166:cytology; D006085:Graft Survival; D006410:Hematopoiesis; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D051379:Mice; D016513:Mice, SCID; D018183:Transplantation Chimera; D014183:Transplantation, Heterologous
D018952:Antigens, CD34