不同细胞因子组合对人脐血单个核细胞体外扩增及CD49d和CXCR4表达的影响

为了探讨不同的细胞因子组合对脐血单个核细胞体外的扩增作用及扩增后CD49d和CXCR4的变化，将新鲜脐血标本分离的单个核细胞接种于含有不同细胞因子组合的无血清无基质培养体系中培养7天，在0天，7天检测有核细胞数，CD34^＋细胞数及CD34^＋CXCR4^＋，CD34^＋CD49d^＋的细胞数和集落形成单位（CFU）数．根据不同细胞因子组合实验分组为：对照组；SF组（SCF＋FL）；SFT组（SCF＋FL＋TPO）和SFT6组（SCF＋FL＋TP0＋IL-6）。结果表明，和对照组相比，SF组合仅能低水平支持脐血造血细胞扩增，加入TPO后即SCF／FL／TPO组合能有效的扩增脐血细胞，但SFT和SFT6两组之间差异却无明显发生（P〉0．05）；SF，SFT和SFT63组的细胞因子组合均可提高脐血CD34^＋细胞CD49d，CXCR4的表达，但3组之间差异无显著性（P〉0．05）。结论：SF组合可协同扩增人造血细胞，但协同作用较弱；TPO在脐血造血干／祖细胞体外扩增中起重要调节作用，而IL-6作用不显著；SCF／FL／TPO 3种因子组合不仅可促进脐血造血祖细胞的扩增，而且可上调脐血造血细胞CD49d，CXCR4表达。

Effect of Different Cytokine Combinations on the Expression of CD49d and CXCR4 and Ex vivo Expansion of Umbilical Cord Blood Mononuclear Cells

This study was purposed to explore the effect of different cytokine combinations on the expansion of the mononuclear cells drived from umbilical cord blood (CB) ex vivo and expression of CXCR4 and CD49d on CD34~+ cells after expansion. Human fresh CB mononuclear cells were cultured in serum-free and stroma-free medium containing different combinations of cytokine for 7 days. At day o and 7, the total cells were counted, CD34~+ cells and CD34~+ CXCR4~+, CD34~+CD49d~+ cells were assayed by flow cytometry, and CFU were determined. According to the different combinations of cytokine, experiments were divided into four groups: control, SF group (SCF+FL), SFT group (SCF+FL+TPO) and SFT6 group (SCF+FL+TPO+IL-6). The results showed that the SF (SF group) combination supported only low expansion of total cells, CD34~+ cells and CFU. The addition of TPO in SF group restored UCB stem/progenitors expansion to a higher level than that in SF group, while there was no difference between groups SFT and SFT6 (P>0.05). The cytokine combinations in groups SF, SFT and SFT6 all could upregulate the expression levels of CD49d and CXCR4 on expanded cord blood CD34~+ cells, but there were no significant differences between groups SF, SFT and SFT6 (P>0.05). It is concluded that SCF+FL has no strong synergistic effects on primitive hematopoietic cells. TPO plays an important role in enhancing expansion of umbilical cord blood hematopoietic cells, while IL-6 only shows a neutral effect on it. SCF+FL+TPO combination not only promotes progenitor cells expansion but also upregulates the expression of CD49d and CXCR4 on CD34~+ cells from cord blood.