Fig. 2

Combination therapy of CD73 blockade and anti-4-1BB facilitates tumor regression. WT mice were injected s.c. with B16-SIY melanoma cells and treated with control IgG, anti-CD73, anti-4-1BB, or both anti-CD73 and anti-4-1BB. a Tumor size was measured every 2–3 days (5 mice per group). b Survival curves of B16-SIY-bearing mice in another independent experiment treated as indicated (8 mice per group). Percentage of CD4⁺ (c) or CD8⁺ (d) among tumor-infiltrating CD45⁺ T cells, and percentage of Foxp3⁺ (e) among total tumor-infiltrating CD4⁺ T cells in the treated B16-SIY-bearing mice as indicated. Ratios of CD4⁺Foxp3^- (effectors) to CD4⁺Foxp3⁺ (Tregs) cells (f), and CD8⁺ to Gr1⁺CD11b⁺ MDSCs (g). Representative flow dot plots for percentage of IFN-γ⁺ in tumor-infiltrating CD8⁺ T cells (h), and the ratio of CD8⁺IFN-γ⁺ to CD4⁺Foxp3⁺ Tregs (i). j Detection of infiltrating SIY-specific CD8⁺ T cells by dimer staining from B16-SIY-bearing mice treated as indicated and (k) representative flow dot plots. l ELISPOT analysis of IFN-γ secreting CD8⁺ T cells from DLN of B16-SIY-bearers treated as indicated in the presence of SIY peptides (3 mice per group). The total number was counted. *p < 0.05, **p < 0.01, ***p < 0.001. ANOVA analysis, log-rank test and unpaired Student’s two-tailed t test were used. Data (mean ± SEM) are representative of at least 2 independent experiments