骨髓间充质干细胞体外对T淋巴细胞分泌IL-2、IL-4功能的影响

Effect of mesenchymal stem cells on IL-2 and IL-4 secretion by T lymphocytes in vitro

目的:探讨间充质干细胞(Mesenchymal stem cells,MSCs)对T淋巴细胞分泌功能的调节作用。方法:体外分离培养、扩增人骨髓MSCs,并通过形态学特征及流式细胞术检测其表面标志加以鉴定。将不同数量的MSCs(5×103、1×104、5×104个细胞/孔)分别与PHA激活的T细胞和混合淋巴细胞反应(MLR)体系共培养,并将不同浓度(25%、50%、75%)的MSCs培养上清和MLR体系共培养。应用ELISA分别检测各培养上清液中T细胞分泌IL-2、IL-4的水平。结果:骨髓MSCs能抑制PHA作用下的T细胞分泌IL-2、IL-4(P<0.05),并呈MSCs数量相关性(P<0.05),且对IL-2的抑制作用更显著;也可抑制MLC体系中T细胞分泌IL-2、IL-4(P<0.05),但各数量组的MSCs的抑制作用无显著性差异(P>0.05)。不同浓度的MSCs培养上清均可抑制MLC体系中T细胞分泌IL-2、IL-4(P<0.05),但不同浓度的MSCs培养上清组对IL-4抑制作用无显著性差异(P>0.05)。结论:骨髓MSCs及其培养上清均可抑制PHA或异体抗原作用下的T细胞分泌IL-2、IL-4,提示MSCs可能是直接作用于T细胞或通过分泌可溶性因子调节Th1/Th2反应平衡而发挥免疫调节作用的。

Objective：To study the immunoregulatory effect of mesenchymal stem cells（MSCs）on the secretive fuction of T lymphocytes.Methods：MSCs from human bone marrow were isolated and culture-expanded.The cells were identified with the spindle-fibroblastic morphology under by microphotograph and the phenotypes were tested by flow cytometry.With various amounts（5×10^3,1×10^4,5×10^4 cells/chamber）,MSCs were added to transformation cultures of T cells induced by PHA and one-way mixed lymphocyte cultures.In addition the supernatant of MSCs,with various concentrations（25%,50% and 75%）,was added to one-way mixed lymphocyte cultures.Then the level of IL-2 and IL-4 were tested by enzyme linked immunosorbent assay（ELISA）.Results：MSCs could reduce both the level of IL-2 and IL-4 secreted by activated T cells in a dose dependent way（P〈0.05）,and IL-2 particularly more obviously.MSCs could reduce the level of IL-2 and IL-4 secreted by activated T cells in the mixed lymphocyte cultures（MLC）（P〈0.05）,but there was no significant difference among different groups（P〉0.05）.The supernatant of MSCs with various concentrations could also reduce the level of IL-2 and IL-4 in the MLC（P〈0.05）,but there was no significant difference among different groups for IL-4（P〉0.05）.Conclusion：Underlying the PHA or variant antigens,MSCs can inhibit the level of IL-2 and IL-4 secretion,and the supernatant of MSCs also inhibit the level of IL-2 and IL-4 secreted by T cells.Thus it suggests that bone marrow-derived MSCs could regulate the balance of Th1/Th2 directly or by secretion of soluble cytokines to perform their immunosuppressive function.