摘要：
目的 探讨不同来源的间充质干细胞(MSC)对滤泡辅助性T细胞(Tfh细胞)的抑制作用及其机制.方法 采用脐带来源MSC(UC MSC)、骨髓来源MSC(BM MSC)、脂肪来源MSC(Fat MSC)分别与外周血单核细胞(PBMC)混合培养48 h,并设立对照组,采用流式细胞仪检测4组培养物中Tfh细胞占淋巴细胞比例,采用酶联免疫吸附试验(ELISA)法检测4组培养物上清中白细胞介素(IL)-21的含量.将BM MSC与PBMC共同培养,分别加入吲哚胺2,3-双加氧酶(IDO)抑制剂1-甲基色氨酸(1-MT)、IL-10抗体、人类白细胞抗原(HLA)-G抗体,分别为1-MT组、IL-10抑制组、HLA-G抑制组,另设不加其他物质的BM MSC组,培养48 h后采用流式细胞仪检测Tfh细胞占淋巴细胞比例.结果 流式细胞术检测结果显示,与对照组比较, BM MSC组Tfh细胞的比例降低,差异有统计学意义(P<0.05);与BM MSC组比较,UC MSC组和Fat MSC组Tfh细胞的比例较高,差异均有统计学意义(均为P<0.05).ELISA结果显示,与对照组比较,BM-MSC组IL-21含量降低,差异有统计学意义(P<0.05);与BM MSC组比较,UC MSC组和Fat MSC组IL-21含量较高,差异均有统计学意义(均为P<0.05).机制研究结果显示1-MT组、IL-10抑制组和HLA-G抑制组Tfh细胞的比例分别为(1.75±0.07)%、(1.31±0.09)%和(1.50±0.03)%,与BM MSC组[(1.03±0.43)%]比较,差异均有统计学意义(均为P<0.05).结论 BM MSC对Tfh细胞分化的抑制效果最好,抑制IL-21的效 果最好,其发挥抑制Tfh细胞分化的机制可能与促进IDO分泌有关.%Objective To investigate the inhibitory effect and underlying mechanism of mesenchymal stem cell (MSC) derived from different sources on follicular helper T cell (Tfh cell). Methods Umbilical cord-derived MSC (UC MSC), bone marrow-derived MSC (BM MSC) and fat-derived MSC (Fat MSC) were co-cultured with peripheral blood mononuclear cell (PBMC) for 48 h. A control group was established. Flow cytometry was adopted to calculate the proportion of Tfh cells among the lymphocytes in four groups. The content of interleukin (IL)-21 in the supernatant was detected by enzyme-linked immune absorbent assay (ELISA) in four groups. BM MSC was co-cultured with PBMC, and supplemented with indoleamine 2,3-dioxygenase (IDO) inhibitor 1-methyl tryptophan (1-MT), IL-10 antibody, human leukocyte antigen (HLA)-G antibody in the 1-MT group, IL-10 inhibition group, HLA-G inhibition group and BM MSC group without addition of other substances. After 48 h culture, flow cytometry was used to detect the percentage of Tfh cells among lymphocytes. Results Flow cytometry demonstrated that compared with the control group, the proportion of Tfh cells in the BM MSC group was significantly decreased (P<0.05). Compared with the BM MSC group, the percentage of Tfh cells in the UC MSC and Fat MSC groups was significantly higher (both P<0.05). ELISA revealed that compared with the control group, the IL-21 content in the BM MSC group was significantly decreased (P<0.05). Compared with the BM MSC group, the IL-21 contents were considerably higher in the UC MSC and Fat MSC groups (both P<0.05). The analysis of underlying mechanism revealed that the proportions of Tfh cells in the 1-MT, IL-10 inhibition and the HLA-G inhibition groups were (1.75±0.07)%, (1.31±0.09)% and (1.50±0.03)%, respectively, which were significantly higher than (1.03±0.43)% in the BM MSC group (all P<0.05). Conclusions BM MSC exerts the highest inhibitory effect upon the differentiation of Tfh cell and IL-21. The mechanism underlying suppressing the differentiation of Tfh cells differentiation is probably correlated to promoting the secretion of IDO.
