Immune Modulatory Effects Of Mesenchymal Stem Cells On T Lymphocytes In Vitro

OBJECTIVE:To investigate the immune modulatory effects of mesenchymal stem cells (MSC)on subsets of T lymphocytes with different stimulations in vitro. The trial was designed to evaluate the role of MSC transplantation in GVHD and GVL, and safety and efficacy of Co-transplantation of hematopoietic stem cells (HSC) and MSC.METHODs: Normal human bone marrow mononuclear cells were isolated by Ficoll-Hypaque density gradient, ex vivo MSCs were culture-expanded,obtained after the third passage .The MSC were added to the two-way mixed lymphocyte culture (MLC) according to different proportion. On day 1, 3 and 5, the proliferation of T lymphocytes of each group of MLC-MSC and ctrl-MLC was measured with MTT colorimetry,and the surface phenotypes and cytokines of T lymphocytes were analyzed by flow cytometry before and after co-culture of MLC with MSC or co-stimulated by PMA and Ionomycin.RESULTs: MLC added MSC induce dose-dependent inhibition of T lymphocytes proliferation, and more effectively in company with co-culture time; CD4+T cell subsets was not suppressed so obviously as CD8+T cell subsets; CD25 expression of T lymphocytes appears to be lower in MLC-MSC than in ctrl-MLC. But the positive cells co-expressing CD4 and CD25 were evidently increase versus control cultures without MSC. The HLA-DR of activated T lymphocytes was slightly decreased in all experiments. Th1 and Tc1 were evidently decreased versus control cultures without MSC. But Th2 and Tc2 were slightly increased .T lymphocytes activated by co-stimulation can be inhibited into Th1 by MSC; In MLC, CD8+T cell subsets and Th1 were evidently decrease versus...