CD133(+) cell selection is an alternative to CD34(+) cell selection for exvivo expansion of hematopoietic stem cells

CD133 is a new stem cell antigen that may provide an alternative to CD34 fo r the selection and expansion of hematopoietic cells for transplantation. T his study compared the expansion capacities of CD133(+) and CD34(+) cells i solated from the same cord blood (CB) samples. After 14 days culture in str oma-free, serum-free medium in the presence of stem cell factor (SCF), Flt3 -1, megakaryocyte growth and development factor (MGDF), and granulocyte col ony-stimulating factor (G-CSF), the CD133(+) and CD34(+) fractions displaye d comparable expansion of the myeloid compartment (CFC, LTC-IC, and E-LTC-I C). The expansion of CD133(+) CB cells was up to 1262-fold for total cells, 99-fold for CD34(+) cells, 109-fold for CD34(+) CD133(+) cells, 133-fold f or CFU-GM, 14.5-fold for LTC-IC, and 7.5-fold for E-LTC-IC. Moreover, the e xpanded population was able to generate lymphoid B (CD19(+)), NK (CD56(+)), and T (CD4(+)CD8(+)) cells in liquid or fetal thymic organ cultures, while expression of the homing antigen CXCR4 was similar on expanded and nonexpa nded CD133(+) or CD34(+) cells. Thus, the CD133(+) subset could be expanded in the same manner as the CD34(+) subset and conserved its multilineage ca pacity, which would support the relevance of CD133 for clinical hematopoiet ic selection.