脐带间充质干细胞体外对脐带血CD4+T淋巴细胞免疫调节作用的研究

摘要

Objective:Immunoregulation study of umbilical mesenchymal stem cell (UCMSCs) on allogeneic umbilical cord blood(UCB) CD4+T lymphocytes,which proliferation,apoptosis and the differentiation to CD4+CD25+ regulatory T cell (Treg) in vitro. Methods:Establishing on direct contact or transwell co-culture system,adopt in different proportion of UCMCs with phytohaemag-glutinin (PHA)-activated UCB CD4+T lymphocytes were co-cultured. The proliferation of lymphocyte,percent of CD4+CD25+/CD4+and Foxp3 expression, regulatory T cell marker gene were measured. Apoptosis of CD4+T lymphocytes were observed in the direct contact or transwell coculture system of UCMSCs with desamethason( DXM)-stimulated UCB CD4+T lymphocytes. Results: The UCB CD4+T lymphocytes cocultured with UCMSCs with PHA-activating for 3 days,compared with the UCMSCs free control group,the amount of cells was reduced noticeably(P<0. 05) and the percent of CD4+CD25+in CD4+T lymphocytes and Foxp3 expression significantly in-creased(P<0. 01) in a dose dependent way(P<0. 05). The UCB CD4+T lymphocytes cocultured with UCMSCs with DXM-inducing for 7 days,the apoptosis rate was significantly lower than that of the control group without UCMSCs (P<0. 01). These effects were partially attenuated in transwell coculture but could not be eliminated. Conclusion: UCMSCs are negative effect on UCB CD4+T lymphocytes-mediated immunity effects,and mainly manifested in the regulation on cell proliferate ability and differentiation rather than promoting apoptosis.%目的：：研究脐带间充质干细胞( UCMSCs)在体外对异源脐血CD4+T淋巴细胞增殖、凋亡及向CD4+CD25+调节性T细胞( Treg)分化的免疫调控作用。方法：建立不同比例UCMSCs与植物血凝素( PHA)活化的脐血CD4+T淋巴细胞共培养，或与Transwell共培养体系，检测CD4+T淋巴细胞增殖情况、CD4+CD25+/CD4+比率的变化及调节性T淋巴细胞标志基因Foxp3相对表达量的变化。同时，建立UCMSCs与地塞米松( DXM)刺激的脐血CD4+T淋巴细胞共培养，或与Transwell共培养体系，检测CD4+T淋巴细胞凋亡情况。结果：PHA活化的脐血CD4+T淋巴细胞在与UCMSCs共培养3 d后，较无UCMSCs对照组相比，细胞数量明显减少(P<0.05)且CD4+CD25+/CD4+T淋巴细胞的比率及Foxp3的相对表达量显著增加(P<0.01)，并随UCMSCs数量增加，作用增强(P<0.05)。 DXM诱导的脐血CD4+T淋巴细胞与UCMSCs共培养7 d后，细胞凋亡比率较无UCMSCs对照组显著降低(P<0.01)。上述效应在Transwell共培养中部分减弱但无法消除。结论：UCMSCs对脐血CD4+T细胞介导的免疫反应具有负调节作用，其作用主要表现在对细胞增殖能力和分化的调控而不是促进凋亡。