Effect of Bone Marrow Mesenchymal Stem Cells on T-Cell Subgroups

The aim of this study was to invesigate the effect of human bone marrow mesenchymal stem cells on human T-cell proliferation resulted from stimulation with PHA and possible immunomodulating mechanism.T cells were positively selected by CD3+ magnetic beads,and were then co-cultured with irradiated MSCs overnight before the addition of PHA.T-cell proliferation was measured by BrdU assay and the degree of apoptosis was assessed by flow cytometry with Annexin V/PI.T cells co-cultured with or without MSCs were treated with PHA for 72 hours,then harvested.They were labeled with anti-CD4,anti-CD8,anti-CD25 antibodies and analyzed by flow cytometry.The results showed that MSCs inhibited T-cell proliferation,but did not induce T cell apoptosis.There were no significant changes in the ratio of CD4+ and CD8+ T cells of MSC-treated group,as compared with the control group.After stimulation with PHA,there was an increase in CD4+ T cells and decrease of CD4+CD25+ cells in MSC co-cultured group.It is concluded that the MSCs inhibit T-cell proliferation after stimulation with PHA,and show more inhibitive effects on CD8+ and CD4+ T cells,but CD25+ regulatory T cells may not be involved in this process.