人骨髓间充质干细胞对T淋巴细胞的免疫调节作用

Immune Regulatory Effect of Human Bone Marrow Mesenchymal Stem Cells on T Lymphocyte

为了探讨人骨髓间充质干细胞(mesenchymalstemcell,MSC)体外对T淋巴细胞的免疫调节作用,从人骨髓液中分离培养MSC,通过细胞形态、免疫组织化学及流式细胞术检测其表面标记进行鉴定;将植物血凝素(PHA)及从人脐血中分离培养的树突状细胞(dendriticcell,DC)作为刺激因素,经磁珠分选的人CD2+T淋巴细胞作为反应细胞,用3H-TdR标记β液体闪烁计数仪检测与MSC共培养前后T淋巴细胞增殖能力的变化;用流式细胞术检测与MSC共培养10天后的CD2+T细胞内各亚群Th1、Th2、Tc1、Tc2比例的变化。结果表明:MSC能明显抑制由DC诱导的T淋巴细胞增殖(P=0.004),同时MSC抑制由PHA引起的T细胞增殖,但不具有显著性差异(P=0.26),MSC培养上清液单独并不具备抑制T细胞增殖的作用,与MSC共培养后的T细胞亚群中,Th2及Tc2亚群含量较共培养前明显增加(P<0.05)。结论:MSC对由DC和PHA诱导的淋巴细胞增殖反应均具有抑制作用,并且这种作用可能与细胞间相互作用及诱导T细胞亚群的改变有关。

To investigate the immune regulatory effects of human bone marrow mesenchymal stem cells on alloantigen T lymphocyte in vitro, human MSCs were isolated and expanded from bone marrow cells, and identified with cell morphology, and the phenotypes were assessed by immunohistochemistry and flow cytometry. As the stimulation factor of T lymphocytes proliferation, either PHA or dendritic cells isolated from cord blood were cocultured with CD2^＋ T lymphocytes from peripheral blood mononuclear cells by magnetic beads with or without MSC in 96-well plats for seven days. T cell proliferation was assessed by [^3H]-thymidine incorporation using a liquid scintillation counter. T cell subsets, Th1, Th2, Tc1 and Tc2 were analyzed by flow cytometry after co-culture of CD2^＋ T cells with MSCs for 10 days. The results showed that a significant decrease of CD2^＋ T cell proliferation was evident when MSC were added back to T cells stimulated by DC or PHA, and an increase of Th2 and Tc2 subsets were observed after co-culture of MSC with T lymphocytes. It is suggested that allogeneic MSC can suppress T cell proliferation in vitro and the cause of that was partly depend on interaction of cells and the alteration of T cell subsets.