The studies on the committed differentiation of human umbilical cord blood CD34~+ cells into lymphocytes ex vivo / 中国免疫学杂志

ABSTRACT

Objective:To establish the technique for T lymphocytes inducted and differentiated by using human hematopoietic stem/progenitor cells ex vivo and to provide a technological platform for studying T cells biological characteristics and cellular immune.Methods:Human CD34-positive cells were isolated from umbilical cord blood by using a high-gradient magnetic cell sorting system(MACS) and CD34+ cells were seeded on human fetal thymic stromal monolayer system.Liquid culture system contains hematopoietic cytokines(FL+IL-12+IL-7+IL-2) and 20% human AB serum.Non-adhension cells were obtained after 7?14?28?35?42 days of culture respectively to analysis T cells phenotype by FACS using T cells specific monoclonal antibody.T cells morphology were also studied.Results:After 2 weeks of culture CD4+CD8+ immature T lymphocytes wre about 0 3%～13 3% and the peak value is 16 6%～26 5% at 4～5 weeks of culture.CD4-CD8+ and CD4+CD8- T cells that coexpressed CD3 cells increased at 26 5%～64 9% and 11 6%～38 9% after 6 weeks of culture.Wright staining shows that the mature T cells harvested after mitogenic stimulation have the presence of large cells with lymphoblast morphology.Conclusion:Human umbilical cord blood CD34+ cells could be differentiated into T lymphocytes by the culture conditions of human fetal thymic stromal monolayer system and the cytokine combination of FL+IL-12+IL-7+IL-2,and the T cells can be stimulated by IL-2+PHA.