[Karyotyping and immunophenotyping analyses of the CD34+ CD38- cells isolated from human umbilical cord blood].

Objective To cultivate hematopoietic stem/progenitor cells (CD34 +CD38 -) isolated from umbilical cord blood (UCB) long termly for the observation of cell growth and expansion in vitro, surface marker expression, and chromosomal complements. Methods By flow cytometry CD34-FITC and CD38-PE labeled CD34 + and CD38 - stem/progenitor cells were isolated from UCB. The cells were cultivated in vitro for 6 months in a stem cell culture system with addition of six kinds of cell growth factors (IL-3, IL-6, GM-CSF, Epo, SCF, IGF-1). One month after cultivation, cultured cells were investigated for surface marker expression by flow cytometry and karyotype by G banding method. Results After 7~12 days cultivation, the CD34 +CD38 - stem/progenitor cells began proliferation. The proliferation rate and the peak proliferation duration were greater in 1 cell/well cultivation conditions than in 10 cells/well. The cells remained CD34 +CD38- and their karyotypic characteristics remained unchanged. Conclusion CD34 +CD38 - stem/progenitor cells from UCB may provide a larger than original amount of stem/progentor cells for transplantation after long-term cultivation in vitro.