脐血CD34^＋细胞体外扩增及树突状细胞诱导的实验研究

目的 研究脐血CD34^＋细胞在体外经造血细胞生长因子扩增后，诱导树突状细胞（DC）并观察该类DC在抗肿瘤免疫中的作用。方法 Ficoll分离脐血单个核细胞，免疫微磁珠法分离纯化CD34^ 细胞，以干细胞因子、flt3配体、白细胞介素－3和红细胞生成素体外扩增2周，诱导DC生成，观察肿瘤抗原负载后诱导特异性细胞毒T淋巴细胞生成和对肿瘤细胞杀伤作用。结果（1）脐血经免疫微磁珠法分离可获得高纯高的CD34^ 细胞；（2）2周体外扩增后，细胞数显著增加达150倍；体外集落试验证实该类细胞可形成粒单细胞集落形成单位／（CFU－GM）；（3）扩增的细胞可成功诱导成DC，并具有活化异体淋巴细胞的功能，负载肿瘤抗原后能诱导发生肿瘤特异性淋巴细胞，并可特异性杀伤Daudi肿瘤细胞。结论 脐血来源CD34^ 细胞在体外能成功地扩增，并诱导产生功能性DC。

CD34+ cells expansion and dendritic cells inducement from umbilical cord blood

Objective To investigate CD34 ce lls expansion in vitro from umbilical cord blood and dendritic cell (DC) inducem ent from these expanded cells and its possible usefulness in antitumor immunity.Methods CD34 cells were purified from mononuclear cell by th e MACS system after density gradient separation. The purified CD34 cells were cultured in medium containing stem cell factor,interleukin-3 (IL-3),flt3 liga nd and erythropoietin for expansion in vitro. After 2 weeks incubation,the cells were induced to DC.The effects of DC pulsed with tumoral antigens on cytotoxic T lymphocytes (CTL) inducement and growth inhibition of Daudi cells were assayed . Results (1)Highly purified CD34 cells were obtained by using immunomicrobeads assay;(2)The cells were expanded to 150 times after two weeks incubation and the expanded cells had the capacity to form gran ulocyte-macrophage colony forming unit (CFU-GM) in vitro;(3)The cells expanded from CD34 cells can be successful induced to mature DC which can ind uce an antitumor response by activating CTL in vitro. Conclusion CD34 cells from cord blood were relatively easy to be expanded and to obain functional DC in vitro.