目的：明确半乳糖凝集素1（galectin-1）在脐带间充质干细胞（umbilical cord mesenchymal stem cells, UC-MSCs）调控类风湿关节炎（rheumatoid arthritis, RA）患者T细胞功能中的作用。方法： 应用慢病毒构建galectin-1低表达的UC-MSCs，即UC-MSCs(Gal-1-)，采用直接接触培养方式分别将UC-MSCs、UC-MSCs(Gal-1-)与RA患者的CD4+ T细胞共培养。设立阴性对照组（CD4+ T）、阳性对照组［CD4+ T培养过程中加入植物血凝素（phytohae-magg lutinin，PHA）2 mg/L］、UC-MSCs-CD4+ T共培养组、UC-MSCs(对照shRNA)-CD4+ T共培养组及UC-MSCs(Gal-1-)-CD4+ T共培养组。MTS法检测CD4+ T细胞增殖，ELISA方法检测共培养上清液中肿瘤坏死因子α（tumor necrosis factors α, TNF-α）水平，流式细胞术检测Th1/Th2/Th17细胞亚型。结果： UC-MSCs和UC-MSCs(对照shRNA)与CD4+ T细胞共培养组可显著抑制PHA诱导的CD4+ T细胞增殖及TNF-α表达，而UC-MSCs(Gal-1-)组对此无明显抑制作用。与阴性对照组（8.51%±2.04%）相比，UC-MSCs及UC-MSCs(对照shRNA)组可显著抑制Th1细胞分化（分别为4.83%±1.37%和5.13%±0.87%，P值分别为0.012和0.018），而UCMSCs(Gal-1-)组对此无明显抑制作用（6.41%±0.96%，P=0.101）。与阴性对照组相比，UC-MSCs及UC-MSCs(对照shRNA)组可上调Th2并下调Th17比例，但差异并无统计学意义，UC-MSCs(Gal-1-)组的这一作用不明显。结论： UC-MSCs可抑制RA患者CD4+ T细胞的增殖、活化并可降低Th1细胞比例，但敲低galectin-1分子的表达后该作用减弱，提示galectin-1参与了UC-MSCs抑制RA患者CD4+ T细胞功能的过程。

Objective： The therapeutic potential of umbilical cord mesenchymal stem cells (UC-MSCs) in rheumatoid arthritis (RA) has attracted more and more attention, because of it can suppress the various inflammatory effects of T cells. Galectin-1 is highly expressed in UC-MSCs, as the first lectin mediating the immunomodulatory effect of MSCs. Our study will investigate the effects of galectin-1 in regulation of UC-MSCs on rheumatoid arthritis T cells. Methods: Lentivirus transfected shRNA technique was used to knock down the expression of galectin-1 in UC-MSCs to construct UC-MSCs(Gal-1-). The effects of UC-MSCs and UC-MSCs(Gal-1-) on CD4+ T cells in RA patients were investigated by contact system, including negative control group (CD4+ T cells), positive control group ［CD4+ T-phytohemagg lutinin (PHA)］, UC-MSCs-CD4+ T cells co-culture group, UC-MSCs(control shRNA)-CD4+ T cells co-culture group, and UC-MSCs(Gal-1-)-CD4+ T cells co-culture group. The proliferation of CD4+ T cells was detected by MTS assay. The level of tumor necrosis factors α (TNF-α) in cells supernatant was detected by enzyme linked immunosorbent assay (ELISA). The effect of UC-MSCs on helper T cell (Th) subset was detected by flow cytometry. Results: In vitro, UC-MSCs were capable of inhibiting PHA induced proliferation of CD4+ T cells from RA patients, but UC-MSCs(Gal-1-) did not show the significant inhibitory effect. Galectin-1 affect the TNF-α level of CD4+ T cells regulated by UC-MSCs. UC-MSCs and UC-MSCs(control shRNA) significantly inhibited the expression of TNF-α in PHA-induced CD4+ T cells. However, UC-MSCs(Gal-1-) had no significant inhibitory effect. Furthermore, the Th1 cells were also significantly suppressed by UC-MSCs and UC-MSCs(control shRNA) (4.83%±1.37% and 5.13%±0.87%，P=0.012 and P=0.018). These was no significant difference in the proportion of the Th1 cells between the control group and UC-MSCs(Gal-1-) group (8.51%±2.04% and 6.41%±0.96%，P=0.101). The Th2 cells were protected after silence galectin-1 in UC-MSCs, whereas there was no significant difference. The proportion of Th17 was decreased by co-culture with UC-MSCs and UC-MSCs(control shRNA), but these was also no significant difference. Conclusion: UC-MSCs can inhibit the proliferation and differentiation of CD4+ T cells from RA patients, but these effect declined after knocking down the expression of galectin-1. Galectin-1 maybe take part in the regulation of UC-MSCs on rheumatoid arthritis CD4+ T cells.