Ex vivo expansion and trilineage differentiation of GD2-selected MSCs. Photomicrograph of undifferentiated, ex vivo–expanded cells (upper panel) after isolation by GD2 selection. The characteristic spindle shape morphology and plastic adherence of MSCs is shown. Immunocytochemical staining (lower panels) demonstrates the differentiation of the GD2-selected MSCs into osteoblasts (Alizarin Red stain), adipocytes (Oil Red O stain), and chondroblasts (Alcian Blue stain).