干扰素γ增强脂肪间充质干细胞对淋巴细胞的免疫调节作用

摘要

Objective To investigate the immunomodulatory effects and the mechanism of interferon (IFN)-γ-pretreated adult autologous adipose tissue-derived mesenchymal stem cells (ADSCs) on peripheral blood lymphocytes. Methods ADSCs were obtained from adult subcutaneous adipose tissues. IFN-γ with and without pretreated ADSCs were used as IFN-γ-pretreated group and IFN-γ-unpretreated group, which were cultured with autologous peripheral blood mononuclear cells (PBMCs) at different concentrations of ADSCs-to-PBMCs ratios in presence of concomitant phytohemagglutinin (PHA)/interleukin (IL)-2 stimulation. After 5 days of culture, the proliferatory inhibitory rate of activated T cells, the percentage of CD4+CD25+ regulatory T cells (Treg), and the expression of indoleamine 2,3-dioxygenase (IDO) mRNA were assessed. Results ADSCs were isolated from autologous adipose tissue, which strongly expressed CD73, CD90, and CD105, as well as displayed adipogenic and osteogenic differentiation. The percentage of CD4+CD25+Treg was significantly higher in IFN-γ-pretreated group than that of IFN-γ-unpretreated group. The expression level of IDO mRNA in ADSCs was significantly increased in IFN-γ-pretreated group than that of IFN-γ-unpretreated group. The proliferation inhibition of activated T cells was significantly decreased in IDO-blocker group than that of IFN-γ-pretreated group (P < 0.01). Conclusion These results suggest that IFN-γ can promote immunosuppressive effects of ADSCs on activated T cells through increased expression of IDO.%目的：观察干扰素（IFN）-γ增强成人自体脂肪间充质干细胞（ADSCs）对外周血淋巴细胞免疫调节的作用及机制。方法取亲体移植供体术中腹部皮下脂肪组织并留取外周血，分离单个核细胞（PBMCs）；分离、培养ADSCs；将IFN-γ预刺激ADSCs（IFN-γ预刺激组）及未刺激ADSCs（未刺激组）分别与PBMCs在植物血凝素（PHA）+白细胞介素（IL）-2刺激条件下共培养5 d后，用MTT法检测活化T细胞增殖抑制率，流式细胞术检测CD4+CD25+调节性T细胞（Treg）比例；实时定量RT-PCR法检测ADSCs内吲哚胺2,3双加氧酶（IDO）mRNA水平；观察共培养细胞加入1-甲基色氨酸（1-MT；IDO阻断组）后活化T细胞的增殖能力。结果分离的自体ADSCs高表达CD73、CD90、CD105；具有分化为成脂和成骨细胞的能力。IFN-γ预刺激组ADSCs显著增强活化T细胞增殖抑制率，呈剂量依赖关系，高于未刺激组；IFN-γ预刺激组CD4+CD25+Treg比例与未刺激组相比显著升高；IFN-γ预刺激组ADSCs内IDO mRNA表达水平显著高于未刺激组；IDO阻断组对活化T细胞增殖抑制率较IFN-γ预刺激组显著降低（P<0.01）。结论 IFN-γ促进ADSCs对活化T细胞免疫抑制能力，IDO在ADSCs介导的免疫抑制中起重要免疫调节作用。