Ex vivo expansion of hematopoietic progenitor cells in human cord blood: an effect enhanced by cord blood serum.

The concept of ex vivo expansion of the human stem/progenitor cell population was tested in this study. Cord blood mononuclear cells were isolated and cultured in the presence of SCF, IL-3, and either cord blood serum (CBS) or fetal calf serum (FCS). After 8 days of incubation with CBS or FCS, the number of CFU-GM was increased ninefold and four-and-a-half-fold, respectively. However, the enhancing effect lasted for only a short period. This study demonstrates that CBS could contain growth factors expanding progenitor cells. Whether the ability of CBS to enhance the CFU-GM expanding capacity is attributable to a novel factor or factors, or represents effects of other known cytokines, remains to be determined.