人脐带间充质干细胞培养上清对正常人淋巴细胞各亚群比例的影响

Influence of supernatant from human umbilical cord-derived mesenchymal stem cells on proportions of each human lymphoid subgroup

目的:研究人脐带间充质干细胞(hUC-MSCs)培养上清对正常人外周血单个核细胞(PBMC)活化、生存及其各淋巴细胞亚群比例的影响。方法:通过密度梯度离心法分离PBMC,加入OKT3刺激,用含有hUC-MSCs培养上清的条件培养基(MSC-CM)处理PBMC,流式细胞术分析比较处理组和对照组各淋巴细胞亚群比例的变化,ELISA法检测MSC-CM对PBMC分泌IFN-γ、IL-10的影响,Annexin V/PI双染确定活化PBMC的凋亡情况。结果:MSC-CM下调了CD4+/CD8+T细胞比值,上调了PBMC中CD4+CD25+CD127lowTreg细胞的含量,而对其他淋巴细胞亚群的比例无显著影响;MSC-CM抑制了PBMCs分泌IFN-γ的能力,但对IL-10的分泌有促进作用;此外,MSC-CM对PBMCs有保护作用,降低了PBMC在OKT3刺激下的凋亡程度。结论:人脐带间充质干细胞的免疫抑制功能可不依赖于与免疫细胞的直接或间接接触,并且与诱导免疫细胞凋亡无关,促进Treg细胞的增殖和活化可能是人脐带间充质干细胞发挥其免疫抑制功能的途径之一。

Objective：To investigate the impact of human umbilical cord-derived mesenchymal stem cells on the activation ,the survival of human peripheral blood mononuclear cell （ hPBMC） and the proportions of each human lymphoid subgroup .Methods：PB-MC were isolated from healthy donors by density gradient centrifugation , then cultured in MSC-CM as treatment group after being acti-vated by OKT3.Each lymphoid subgroup proportion was analyzed by flow cytometry to observe the difference between treatment and control group .The effect of MSC-CM on activated PBMC for the production of IFN-γand IL-10 were tested by ELISA .The level of ap-optosis was assessed by flow cytometry with Annexin-V/PI as fluorescent marker .Results：Compared with the control group , MSC-CM down-regulated the ratio of CD4^ ＋T cell to CD8^ ＋T cell, and increased the proportion of CD4^ ＋CD25^ ＋CD127low Treg cell, thus other subgroup had no significant difference .MSC-CM inhibited the production of IFN-γby PBMC, but promoted the secretion of IL-10, and protected PBMCs from apoptosis when activated with OKT 3.Conclusion：hUC-MSC may play a role of immunosuppression by promo-ting the proliferation and activation of Treg cell .This kind of inhibitory activity is neither relied direct or indirect contact with the lym -phocytes , nor influenced by inducing immune cells apoptosis .