[Immune modulatory effects of mesenchymal stem cells on T lymphocytes in mixed lymphocyte culture].
OBJECTIVE
To investigate the features of immune modulatory function derived from the interaction of mesenchymal stem cells (MSC) with T lymphocytes in vitro.


METHODS
Normal human bone marrow mononuclear cells were isolated by Ficoll-Hypaque density gradient, then ex vivo MSCs were cultured, expanded, and obtained after the third passage. The MSCs were added to the two-way mixed lymphocyte culture (MLC) according to different proportion. On day 3 and 5, proliferation of T lymphocytes in each group of MLC-MSC and ctrl-MLC was measured with MTT colorimetry. The surface phenotypes of T lymphocytes were analyzed by flow cytometry before and after co-culture of MLC with MSC.


RESULTS
MLC added with MSC induced dose- and time-dependent inhibition of T lymphocytes proliferation. CD4(+) T cell subsets were not suppressed so obviously as CD8(+) T cell subsets. CD25 expression of T lymphocytes appeared to be lower in MLC-MSC than in ctrl-MLC. But the CD4(+) CD25(+) double positive cells were evidently increased versus control cultures without MSC. The HLA-DR of activated T lymphocytes was slightly decreased compared to the control.


CONCLUSIONS
MSC can significantly suppress T lymphocytes' proliferation, especially CD8(+) T cell subsets (CTL). In addition, it can down-regulate the expression of some special surface marker, such as CD25 and HLA-DR, on the activated T lymphocytes.
Xuan
Min
M
Department of Hematology, Third Affiliated Hospital, Soochow University, Changzhou 213003, China. xuanmin17@sina.com
Qiu
Guo-qiang
GQ
Xie
Xiao-bao
XB
D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism; D001853:Bone Marrow / Q000276:immunology; D049109:Cell Proliferation; D002478:Cells, Cultured; D015536:Down-Regulation / Q000276:immunology; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D013997:Time Factors
D000954:Antigens, Surface