同种异基因成骨细胞对混合淋巴细胞反应体系中T细胞的免疫抑制

背景：由同种异基因骨髓间充质干细胞诱导的成骨细胞移植免疫反应各家报道不一致，差别明显。 目的：体外观察由骨髓间充质干细胞诱导而成的成骨细胞对T细胞的免疫调节作用及特点。 方法：用Ficoll-Hypaque梯度密度离心法分离出兔骨髓单个核细胞，体外扩增，获取第3代细胞，经典化学方法诱导为成骨细胞，将其按照不同的比例加入到T细胞形成双向混合淋巴细胞培养体系中，在第3，5，7天，用MTT比色法检测各组混合淋巴细胞培养体系中的T细胞增殖情况，24 h后用流式细胞仪分析各组T细胞亚群凋亡情况。 结果与结论：诱导后成骨细胞混合淋巴细胞培养体系中，成骨细胞对T细胞的增殖有抑制作用，在一定范围内，抑制作用具有量效关系。诱导后成骨细胞剂量大，时间延长，抑制程度增强；3次平均抑制率相比：1∶20组低于1∶80组(P < 0.01)；1∶40组低于1∶80组(P < 0.05)；诱导后成骨细胞能引起T细胞亚群凋亡，其中CD4+(凋亡率8.57%)亚群不如CD8+(凋亡率15.31%)细胞亚群凋亡显著(P < 0.01)。结果显示诱导的成骨细胞在体外能够通过细胞凋亡途径抑制T细胞的增殖，特别是CD8+。但这种抑制不是特别强，表明诱导的成骨细胞虽有一定的免疫性，但其免疫性较低。

Immunosuppression of allogeneic bone marrow-derived mesenchymal stem cells-induced osteoblasts on T cells in mixed lymphocyte culture system

BACKGROUND: Results of immunclogical response of allogeneic bone marrow-derived mesenchymal stem cells-induced osteoblast transplantation are varied. OBJECTIVE: To investigate the features of immune adjustment function derived from the interaction of osteoblasts derived from mesenchymal stem cells (ODCs) with T cells in vitro. METHODS: Rabbit bone marrow mononuclear cells were isolated by Ficoll-Hypaque density gradient, ex vivo culture-expanded, and obtained after the third passage. The classic chemical induced ODCs at different proportion were added to T cells to form two-way mixed lymphocyte culture system. At 3, 5, 7 days, MTT assay was used to detect T cell proliferation in each group. T-cell subsets apoptosis was analyzed using flow cytometric analysis after 24 hours. RESULTS AND CONCLUSION: ODCs inhibited T cell proliferation in a dose-effect manner in a certain range. With increasing ODC dose and time, inhibition was enhanced. Comparison of mean inhibition rate of three times showed that (1: 20) group was less than (1: 80) group, and (1: 40) group was less than (1: 80) group (P < 0. 05). ODCs can cause apoptosis of T cell subsets, including CD4+ (apoptosis rate 8.57%) subtypes less than CD8+ (apoptosis 15.31%; P < 0.01). Results showed that ODCs in vitro can suppress T cells proliferation through pathway of cell apoptosis, especially for CD8+. However, this inhibition is not particularly strong, showing that the ODCs have some degree of immunity, but it is very low.