[Engineering of hematopoietic cells and the hematopoietic reconstitution of expanded cells in SCID mice].

OBJECTIVE

To elucidate the roles of cytokines for ex vivo expansion and orderly differentiation of hematopoietic progenitor cells, and the capacity of hematopoietic reconstitution of the expanded cells.

METHODS

CD34+ cells were isolated from umbilical cord blood by using a high-gradient magnetic cell sorting system (MACS), and expanded with the different combinations of cytokines in a liquid culture system. The expanded cells were then transplanted into sublethally irradiated SCID mice.

RESULTS

The combination of cytokines including FL, SCF, TPO, etc. increased total cells, progenitor cells(CFU-GM and CFU-MK), and CD34+ CD38- early progenitor cells by (2,130 +/- 57), (70 +/- 7), (118 +/- 11) and (46 +/- 5) folds, respectively. The percentage of dendritic cells (24.3 +/- 2.1)% was also much higher than the control(0.4 +/- 0.3)%. The CD34+ CD38- subsets and the combination of FL and TPO were identified as the most potential for expanding early progenitor cells. The expanded cells could smoothly engraft SCID recipients and reconstitute their hematopoiesis. Furthermore, human hematopoietic cells and could be detected in marrow cells from SCID mice transplanted 6 weeks late.

CONCLUSIONS

It is possible to expand hematopoietic cells ex vivo efficiently and maintain the hematopoietic reconstitution capacities of hematopoietic stem/early progenitor cells by an appropriate combination of cytokines. The engineering of hematopoietic cells--the new generation of cellular therapeutics are now underway in the applications of stem cell transplantation, immunotherapy of cancers, and gene therapy.