SEPARATION, ENRICHMENT, AND CHARACTERIZATION OF HUMAN HEMATOPOIETIC PROGENITOR CELLS FROM UMBILICAL-CORD BLOOD

Human umbilical cord blood (UCB) may be used as an alternative source of bone marrow repopulating cells in allogeneic bone marrow transplant ation in children. It has been reported that high numbers of hematopoi etic progenitor cells (HPC) from umbilical cord blood may be lost duri ng simple cell-separation techniques. This may seriously hamper the us e of UCB as an alternative source of bone marrow repopulating cells. I n this study we demonstrate that UCB can be separated into various cel l fractions using several cell-separation methods including red blood cell lysis, methylcellulose sedimentation, and density gradients witho ut significant loss of HPC, when cell separations are initiated within 8 h. We demonstrate that UCB contains a high concentration of immatur e HPC as compared with bone marrow grafts. Using FACS analysis of cell s harvested from single colonies derived from single cell- single well -sorted CD34+ +CD33- UCB cells, the high frequency of multipotential H PC was illustrated. These results suggest that UCB may contain suffici ent HPC for hematopoietic stem cell transplantation in adults.