间充质干细胞对活化T淋巴细胞的免疫调节作用

本研究的目的是探讨骨髓间充质干细胞（MSC）对活化T淋巴细胞的免疫调节作用及其在allo—HSCT相关GVHD防治中的作用。用终浓度为10μg/ml的PHA于不同时间作用T淋巴细胞，以^3H—TdR掺入法检测T细胞增殖功能；以不同数量的MSC分别与活化T淋巴细胞作用，根据MSC数量不同实验分为A组（对照组，不加MSC）、B组（MSC2×10^4）、C组（MSC4×10^4）、D组（MSC8×10^4），用^3H—TdR掺入法检测作用前后T细胞功能，FCM检测细胞免疫表型。结果显示，在终浓度为10μg／ml PHA作用下，T淋巴细胞的增殖能力随培养时间的延长而增强，48小时达高峰。FCM检测MSC细胞表型表明：CD44、CD105、CD29、FIK1表达阳性，不表达CD33、CD34、CD45、HLA—DR。随着MSC数量增加，与共培养前相比，T细胞的SI值逐渐降低（P〈0．05），但C组和D组间比较无差异（P〉0．05）。在低数量MSC作用下，CD3^＋CD4^＋表达低于对照组（P〈0．05），CD4^＋CD25^＋、CD4^＋CD152^＋高于对照组（P〈0．05）；C组和D组与对照组相比，CD3^＋CD4^＋表达明显降低（P〈0．01），CD3^＋CD8^＋、CD4^＋CD25^＋、CD4^＋CD152^＋明显增高（P〈0．01）。结论：丝裂原PHA可以使T细胞活化；骨髓MSC在体外可以使活化T细胞功能和细胞免疫表型发生改变，下调CD3^＋CD4^＋的表达，上调CD3^＋CD8^＋、CD4^＋CD25^＋、CD4^＋CD152^＋的表达。

Immunoregulatory Effect of Mesenchymal Stem Cells on Active T Lymphocytes

This study was purposed to explore the immunoregulatory effects of human bone marrow mesenchymal stem cells (MSCs) on active T lymphocytes in vitro and the new strategy to prevent graft-versus-host disease (GVHD) in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Mononuclear cells from human peripheral blood cells were isolated and cultured in the presence of phytohemagglutinin (PHA) (final concentration was 10 microg/ml) for different times. The ability of T lymphocyte proliferation and activation was measured by (3)H-Thydimine incorporation. The expressions of CD3(+)CD4(+), CD3(+)CD8(+), CD4(+)CD25(+) and CD4(+)CD152(+) on T cells were detected by FCM after coculture for 72 hours. Experiment was divided into 4 groups: A group as control (no added MSCs), B group (actived T cells + 2 x 10(4) MSCs), C group (actived T cells + 4 x 10(4) MSCs), D group (actived T cells + 8 x 10(4) MSCs). The results showed that the ability of T lymphocyte proliferation in the same PHA concentration increased with prolonging of time. ability of T lymphocyte proliferation was strongest when culturing for 48 hours (p < 0.01); the expressions of CD44, CD105, CD29 and FIK1 of MSCs were positive, expressions of CD33, CD34, CD45 and HLA-DR were negative. MSCs inhibited T lymphocyte proliferation and the inhibitory effect depended on the amount of MSCs. CD3(+)CD8(+), CD4(+)CD25(+) and CD4(+)CD152(+) T cells cocultured with MSCs increased obviously and CD3(+)CD4(+) expression significantly decreased, as compared with control group (p < 0.01). It is concluded that the MSCs inhibit T lymphocyte proliferation induced by mitogen (PHA), and perform their immunosuppressive function by up-regulation of CD3(+)CD8(+), CD4(+)CD25(+) and CD4(+)CD152(+) expressions and down-regulation of CD3(+)CD4(+) expression.