Ad-hLIF转基因饲养层细胞对CD34+造血干/祖细胞增殖和分化的影响

目的 用腺病毒载体介导的人白血病抑制因子基因(Ad-hLIF)感染WI-38人胚肺成纤维细胞制备饲养层细胞,体外观察转基因细胞对CD34+造血干/柑细胞增殖和分化的影响,体内研究对辐射损伤SCID小鼠造血功能恢复的效果.方法 用RT-PCR和ELISA法鉴定Ad-hLIF转基因饲养层细胞目的 基因的表达后,将经免疫磁珠法分离和流式细胞术检测后的CD34+细胞在饲养层和/或细胞因子培养体系中扩增28 d,检测不同时间点的单个核细胞(MNC)数量及CD34+细胞阳性率;扩增后的MNC经CFDA SE荧光标记后移植入辐射损伤SCID小鼠体内,RT-PCR和细胞荧光标记法检测小鼠内含Alu基因人源细胞的门巢情况.结果 感染50MOI(multiplicity of infection)Ad-hLIF的饲养层细胞均有绿色荧光,RT-PCR和ELISA法结果 显示hLIF目的 基因能在WI-38饲养层细胞中表达,免疫磁珠法分离的CD34+造血干/祖细胞经流式细胞术检测其纯度可达95.60%±2.58%,MNC在Ad-hLIF转基因饲养层培养体系持续扩增,最高可达356.95±0.87倍,其中CD34+细胞仪在0～14 d能维持较高水平,最高可扩增52.11±1.13倍,以后逐渐降低.将其移植辐射损伤SCID小鼠后,可明显提高小鼠存活率,4周内小鼠骨髓中不仅可观察到CFDA SE荧光标记的细胞,而且经RT-PCR法搭定后.还可检测到表达Alu人源基因的人脐血造血归巢细胞.结论 成功建立的Ad-hLIF转基因饲养层细胞不仅体外可以有效地扩增CD34+造血干/祖细胞,并延缓其分化.扩增的CD34+细胞对辐射损伤SCID小鼠具有造血功能恢复的功能.

Effect of feeder cells transduced with Ad-hLIF on the expansion of CD34+ cells in indirect co-culture

Objective To establish Ad-hLIF transgenic feeder cells for the expansion of umbilical cord blood CD34+ HSPC in vitro and study the SCID mice model of hematopoietic stem/progenitor cell (HSPC) transplantation. Methods The expression of objective gene in Ad-hLIF transgenic feeder cells was detected by RT-PCR and ELISA. The purity of umbilical cord blood CD34+ HSPC separated by magnetic-activated cell sorting(MACS) was detected by the flow cytometry. After expanded with various combinant of cytokines and transgenic feeder layer cells for 28 d, the quantity of mono-nuclear cell (MNC) and CD34+ cells rate was detected in different time. MNC after expansion stained by CFDA SE was injected to the sublethally irradiated SCID mice. Humanize gene Alu was detected by RT-PCR and fluorescence microscope. Results The green fluorescence was observed in the transgenic cells infected with 50MOI( multiplicity of infection) Ad-hLIF, and the objective gene was confirmed by RT-PCR and ELISA. The purity of umbilical cord blood CD34+ HSPC separated by MACS could reach 95.60% ±2.58%, Ad-hLIF transgenic feeder cells and various cytokines system increased MNC by 356.95±0.87 fold, and maximal expansion of CD34+ cells was observed during 0-14 d of culture, then down-expansion gradually. Four weeks after transplanted in SCID mice, fluorescently-labeled humanize cells still can be observed. The existence of the humanized gene Alu was confirmed by RT-PCR. Conclusion Ad-hLIF transgenic feeder cells can effectively proliferate umbilical cord blood CD34+ HSPC in vitro and delay it differentiate, what's more, it has high transplant efficacy and haematogenesis activity.