Effect of addition of FLT-3 ligand and megakaryocyte growth and development factor on hemopoietic cells in serum-free conditions.

The aim of this study was to clarify the mechanisms that regulate hematopoietic cell expansion in vitro by identifying defined culture conditions. We report the results of experiments with CD34+ cells from cord blood (CB, = 13), bone marrow (BM, = 4), and mobilized peripheral blood stem cells (PBSC, = 5) using two combinations of cytokines: (A) granulocyte colony-stimulating factor (G-CSF), interleukin-3 (IL-3), interleukin-6 (IL-6), stem cell factor (SCF), erythropoietin (EPO), insulin- like growth factor-1 (IGF-1), basic fibroblast growth factor (FGF-b) and (B) combination A plus FLT3 ligand (FL) and megakaryocyte growth and development factor (PEG rhMGDF). Cultures of immunoselected CD34+ cells were performed in serum-free liquid medium without serum substitutes. The area under the curve (AUC) obtained by plotting the logarithm of the total number of viable cells, CD34+ cells, and CFC per well, toward the week of culture was used as an index of cell expansion. With CB, a significant difference was obta...