Different growth factor requirements for the ex vivo amplification of transplantable human cord blood cells in a NOD/SCID mouse model.
The growth factor combination containing early acting cytokines FLT-3 ligand (FL), Stem Cell Factor (SCF) and thrombopoietin (TPO) is able to maintain, for an extended culture period, early stem cells, defined as long-term repopulating NOD/SCID mice (Scid Repopulating Cell-SRC) contained in cord blood (CB). In this culture system, the role of IL-6 and IL-3 has not been clearly established. Using a combination of FL+TPO+SCF with or without IL-6, we were able to form CB CD34+ cells for 30 weeks. The CB CD34+ cells cultured in this system engrafted NOD/SCID mice after 6 weeks of culture; the cells from primary recipients were also able to engraft secondary NOD/SCID mice. When CB CD34+ cells were cultured in the presence of IL-3 in the place of IL-6 we observed an even better expansion of cells and a similar clonogenic progenitor output in the first 8 weeks of culture. However, more primitive LTC-IC output increased up to week 6 with the growth factor combination containing IL-3 and then decreased and disappeared, while with the growth factor combination with or without IL-6 increased up to week 23. Cells cultured for 4 weeks with the 4-factor combination containing IL-3 engrafted NOD/SCID mice less efficiently. Repopulation of NOD/SCID mice was no longer observed when ex vivo expansion was performed for 6 weeks. This study provides some evidence that no differences could be detected in long-term maintenance and even expansion of human primitive cord blood cells cultured with FL+TPO+SCF in the presence or absence of IL-6. Under the culture conditions employed in this study, the presence of IL-3 reduced the repopulating potential of expanded CB CD34+ cells.
Bruno
S
S
University of Torino Medical School, (Division of Clinical Oncology), the Institute for Cancer Research and Treatment (IRCC), Candiolo, Italy.
Gammaitoni
L
L
Gunetti
M
M
Sanavio
F
F
Fagioli
F
F
Aglietta
M
M
Piacibello
W
W
D000818:Animals; D016207:Cytokines / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology*; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID
D016207:Cytokines; D016298:Hematopoietic Cell Growth Factors