Characterization of hUC-MSCs. (A) Morphological observations of hUC-MSCs. Umbilical cord tissues were cultured for >15 days and long spindle-shaded fibroblastic cells were observed around the tissue using Zeiss light microscopy (scale bar, 100 µm). (B) Phenotyping of hUC-MSCs. hUC-MSCs were stained with a fluorescein-labeled antibodies (CD34, CD45, CD73, CD90, CD105, CD14, CD19 and HLA-DR) and analyzed with a flow cytometer. (C) Adipogenic and (D) osteogenic differentiation of hUC-MSCs. hUC-MSCs were cultured in adipogenic and osteogenic medium, respectively. Lipid droplets in the adipocytes are presented with Oil Red O staining (scale bar, 100 µm). hUC-MSCs-derived osteoblasts were detected with Alizarin Red staining (scale bar, 200 µm). (E) hUC-MSCs inhibit the proliferation of CFSE-labeled CD4+ T cells, which were activated by Con A stimulation. Experiments were repeated three times and representative graphs and images are presented. hUC-MSC, human umbilical cord-derived mesenchymal stem cell; MSC Sup, culture supernatant of hUC-MSCs; Con A, concanavalin A; CFSE, carboxyfluorescein succinimidyl ester.