Figure 8. Allo-iMSC/CCL19 therapy combined with anti-PD-L1 antibody exerts anti-tumor effect in aged mice (A) Renca-bearing mice were i.t. injected with allo-iMSC/CCL19 on days 10 and 13 after tumor inoculation. Control IgG or anti-PD-L1 antibody (200 µg) were i.p. administrated on days 13 and 16. The tumor growth in individual mice (left) and the mean±SD (right) are shown. (B) CT26-bearing mice were i.t. injected with allo-iMSC/CCL19 on days 10 and 13 after tumor inoculation. Control IgG or anti-PD-L1 antibody (200 µg) were i.p. injected on days 13 and 16. The tumor growth in individual mice is shown. (C, D) On day 28, the spleen was harvested from each group in (A) and stimulated mitomycin C-treated C57BL/6-derived splenocyte. 48 hours after co-culture, secretion of IFN-γ (C) and TNF-α (D) was measured by ELISA. (E) Cured mice treated with allo-iMSC/CCL19 or combination were s.c. inoculated with CT26. The mean±SD of tumor growth is shown. (F) 53 weeks old aged BALB/c mice were s.c. inoculated with CT26. PBS or allo-iMSC/CCL19 were i.t. injected on days 10 and 13 and control IgG or anti-PD-L1 (200 µg) antibody were i.p. injected on days 13 and 16. The tumor growth in individual mice (left) and the mean±SD (right) are shown. *p<0.05, **p<0.01 by Tukey (analysis of variance). These experiments were performed twice. CCL19, (C-C motif) ligand 19; IFN, interferon; iMSC, immortalized mesenchymal stem cell; i.p., intraperitoneal; i.t., intratumoral; N.S., not significant; PBS, phosphate-buffered saline; PD-L1, programmed death-ligand 1; s.c., subcutaneously.