RESUMEN
<p><b>OBJECTIVE</b>To isolate CD133(+) hematopoietic progenitor cells from human umbilical cord blood and optimize the culture condition for maintaining their stem cell characteristics.</p><p><b>METHODS</b>CD133(+) hematopoietic progenitor cells were isolated from human umbilical cord blood using magnetic cell sorting system, and the cells were detected by flow cytometry. Four methods were used for culturing cells. After 8 weeks' culture, cytomorphology, flow cytometry, immunocytochemistry and immunofluorescence assay were used to identify the characteristics of the stem cells.</p><p><b>RESULTS</b>Over 80% of CD133(+) hematopoietic progenitor cells were isolated from human umbilical cord blood using magnetic cell sorting system. The cells were effectively expanded using optimized serum-free medium after 8 weeks of cell culture, whereas the cells in other media differentiated into adherent cells in a poor state.</p><p><b>CONCLUSION</b>The optimized serum-free medium allows effective expansion of CD133(+) hematopoietic progenitor cells that maintain stem cell characteristics after a long-term culture.</p>