[Immune regulatory effect of human bone marrow mesenchymal stem cells on T lymphocyte]

To investigate the immune regulatory effects of human bone marrow mesenchymal stem cells on alloantigen T lymphocyte in vitro, human MSCs were isolated and expanded from bone marrow cells, and identified with cell morphology, and the phenotypes were assessed by immunohistochemistry and flow cytometry. As the stimulation factor of T lymphocytes proliferation, either PHA or dendritic cells isolated from cord blood were cocultured with CD2(+) T lymphocytes from peripheral blood mononuclear cells by magnetic beads with or without MSC in 96-well plats for seven days. T cell proliferation was assessed by [(3)H]-thymidine incorporation using a liquid scintillation counter. T cell subsets, Th1, Th2, Tc1 and Tc2 were analyzed by flow cytometry after co-culture of CD2(+) T cells with MSCs for 10 days. The results showed that a significant decrease of CD2(+) T cell proliferation was evident when MSC were added back to T cells stimulated by DC or PHA, and an increase of Th2 and Tc2 subsets were observed after co-culture of MSC with T lymphocytes. It is suggested that allogeneic MSC can suppress T cell proliferation in vitro and the cause of that was partly depend on interaction of cells and the alteration of T cell subsets.