Immunomodulatory characteristics of human umbilical cord mesenchymal stem cells in vitro / 中国组织工程研究

ABSTRACT

BACKGROUND: Human umbilical cord mesenchymal stem cells (hUC-MSCs) have been drawing a great attention due to their potential therapeutic effect in a variety of diseases, including immune-mediated diseases. Further characterization of the immunomodulatory properties and action pathways of hUC-MSCs is necessary to ensure their safety and effectiveness in clinical application. OBJECTIVE: To investigate the immunomodulatory properties of hUC-MSCs. METHODS: HUC-MSCs were directly co-cultured with CFSE-labeled peripheral blood mononuclear cells (PBMCs) at the ratio of 15, 110, and 120, or indirectly co-cultured with CFSE-labeled PBMCs at the ratio of 15 via the Transwell co-culture system. Phytohemagglutinin- stimulated PBMC proliferation and the percentages of Th1, Th17 and Treg subgroups in the CD4+ T cells were determined by flow cytometry. The levels of tumor necrosis factor α and interferon γ were determined by ELISA. RESULTS AND CONCLUSION: After direct co-culture, hUC-MSCs significantly inhibited the phytohemagglutinin-stimulated PBMCs proliferation in a dose-dependent manner, whereas the inhibitory effect disappeared in the Transwell co-culture system. A significant decrease of Th1, Th17 cells and an increase of Treg cells were detected in the PBMCs co-cultured with hUC-MSCs compared to the PBMCs cultured alone. Furthermore, hUC-MSCs co-culture significantly reduced tumor necrosis factor α and interferon γ levels in the PBMCs. These findings indicate that cell-to-cell contact is essential for hUC-MSCs to inhibit the proliferation, differentiation and inflammatory factor secretion of immune cells.