CD271和CD133果真能用于脐血间充质干细胞阳性分选吗?

众多研究表明,脐血中存在间充质干细胞(mesenchymal stem cells,MSC),且脐血获得过程简单,对供者没有损伤,因此可以作为MSC的另一个来源,但脐血间充质干细胞含量极少。本研究探讨CD271和CD133免疫磁珠阳性分选是否也能富集脐血中数量极少的MSC。采用免疫磁珠阳性分选方法从脐血单个核细胞(UCB-MNC)中分离得到CD271+、CD271-、CD133+和CD133-4种细胞;将得到的细胞分别进行培养,以未分选的UCB-MNC为对照,观察各组细胞成纤维细胞集落(CFU-F)形成能力;利用流式细胞术、成骨及成脂肪定向诱导分化对MSC进行鉴定。结果表明:CD271和CD133阳性细胞纯度均达85%,但是CD271+细胞中(99.76±0.08)%表达CD45,(6.24±0.03)%表达CD34,而CD133+细胞99%以上都表达CD34和CD45。阳性细胞培养可见单个成纤维样细胞贴壁生长,但不能形成集落并融合,两种阴性细胞中部分标本(约27%)可形成集落,并能融合传代,与对照组(UCB-MNC)培养成功率相似。将两种阴性细胞培养得到的MSC培养至第3代,表型测定基本一致,即CD34-、CD45-、CD14-、CD29+、CD44+、CD73+、CD90+、CD105+,而且具有成骨、成脂肪分化潜能。结论:CD271和CD133不是完全重合的一群细胞,但绝大多数为造血细胞,不能有效的用以扩增MSC。阴性细胞培养成功率与传统贴壁法相似,说明MSC多存在于CD271和CD133阴性细胞中。

Are CD133 and CD271 Useful in Positive Selection to Enrich Umbilical Cord Blood Mesenchymal Stem Cells

It is well accepted that umbilical cord blood has been a source for mesenchymal stem cells.However,there was less success in culturing these cells by using traditional method.Lots of studies showed that CD271（low affinity nerve growth factor receptor LNGFR） and CD133 could be used to positive sort of bone marrow-derived mesenchymal stem cells（MSC） in recent years.The present study was designed to explore whether the method of positive sorting of umbilical cord blood-derived MSC（UCB-MSC） was effective by using CD271 and CD133 immunomagnetic beads.The ability of forming CFU-F and differentiation capacity of the four kinds of cells,namely CD271＋,CD271-,CD133＋ and CD133-were analysed.The results indicated that the purities of immunomagnetically selected CD271＋and CD133＋cells were（87.58±0.48） % and（89.89 ±8.10） % respectively.More than 99% of CD271＋ and CD133＋ cells expressed CD34 and CD45,the markers of hematopoietic stem cells.CFU-F assay showed that CD271＋ and CD133＋ cells could not form any CFU-F and only few single fibroblast-like cells could be found in the dishes.However,part of the negative samples（27%） could form CFU-F.Phenotype of cells（passage 3） isolated by the two methods was the same,that was CD34-,CD45-,CD14-,CD29＋,CD44＋,CD73＋,CD105＋ and CD90＋.They both had osteogenic and adipogenic differention potential.It is concluded that nearly all the CD271 and CD133 positive cells are hematopoietic cells,MSC can be effectively collected by negative selection with immunomagnetic beads against CD271 and CD133.