Fig. 1

Systematic quality evaluation of clinical-grade IL10-MSCs. A The IL10 protein level in the supernatant of different IL10-MSCs clones (P5-6). MSCs with blank vector transfection were the control. B With the increase in the number of passages, the IL10 secretion gradually decreased in IL10-MSCs, but still sustained a high level. C Morphological characterization of IL10-MSCs (P6) compared with naïve MSCs (P6) under light microscopy. D Representative karyotype analysis. Control MSCs (left, P6) and IL10-MSCs (right, P6) both had normal karyotypes. E Flow cytometric analysis showed IL10-MSCs were positive (> 95%) for mesenchymal lineage markers (CD73, CD90, and CD105) and negative (< 2%) for hematopoietic and endothelial markers (CD14, CD19, CD34, CD45, and CD3) as well as for HLA-DR, in accordance with the criteria of clinical-grade MSCs. F1–2 Tumorigenesis analysis showed that there was no tumor formation observed in any SCID mice injected with IL10-MSCs, but tumor was formed in positive control SCID mice with HESCs transplantation. Further H&E staining showed no infiltration of tumor cells at the cell injection site and main organs after IL10-MSC injection. G–I Differentiation potential of IL10-MSCs in adipocytes, osteocytes, and chondrocytes stained with Oil red O, Alizarin Red, and Alcian Blue, respectively. IL10-MSCs maintained multiple lineage potential, but with downregulated adipogenic differentiation capability