[Functional expression of Flt3 and c-kit on cord blood CD34(+) stem/progenitor cells and its significance].

To investigate the expression and function of the receptors of early-acting cytokines on cord blood CD34(+) hematopoietic stem/progenitor cells, the studies of Flt3 and c-kit were undertaken at the gene and protein levels. Fresh and cultured cord blood CD34(+) stem/progenitor cells were analyzed by flow cytometric two-color direct immunofluorescence methods and RT-PCR, while function of receptors was studied in vitro. It was found that (68.8 +/- 15.4)% of CD34(+) cells expressed Flt3, (50.6 +/- 12.7)% of CD34(+) cells expressed c-kit, the proportion of CD34(+) cells expressing Flt3 and c-kit decreased as in vitro culture time extended. It was concluded that cord blood CD34(+) stem/progenitor cells are capable of expressing Flt3 and c-kit for as long as 2 - 3 weeks in liquid medium, during the first week of culture, SCF and FL enhanced the generation of cells and progenitors notably.