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[Ex vivo expansion of CD34+ cells from human umbilical cord blood by FL gene transfected bone marrow stromal cells].

The object of this study was to explore the effect of FL gene transfected marrow stromal cells on expansion of human cord blood CD34(+) cells ex vivo. A co-culture system was established with FL gene transfected human marrow stromal cells and cord blood CD34(+) cells. The CD34(+) cells were cultured in different culture systems with different combinations of stromal cells and SCF, IL-3 and FL. The numbers of total nucleated cells, CFCs and CD34(+) cells were repeatedly counted in culture systems for 3 weeks. The results showed that the FL transgenic marrow stromal cell feeder layer significantly enhanced the expansion of total nucleated cells, CFC and CD34(+) cells, compared with stromal cell feeder layer and stromal cell-free culture systems. The transgenic stromal cells and cytokines co-culture system manifested the most potent expansion of the cord blood cells with increase of the number of total nucleated cells by (122.5 +/- 4.3)-fold, CFCs by (39.6 +/- 2.7)-fold and CD34(+) cells by (11.8 +/- 0.52)-fold. It is concluded that human umbilical cord blood CD34(+) cells can be extensively expanded ex vivo by using FL gene transfected stromal cells combined with cytokines.