Fig. 4

Combined IRT-ICB therapy for inhibiting metastatic tumor using such Mn-based radiosensitizers-activated systematic immune responses on the bilateral 4T1 tumor-bearing mice. a Immunohistochemical images of tumor slices to show the expression levels of PD-L1 on tumor cells collected from mice. b Schematic of experimental procedures on the abscopal bilateral 4T1 tumor model for IRT-ICB therapy. c, d Primary (c) and distant (d) tumor growth curves of mice after treatments with anti-PD-L1, ¹³¹I-MnO₂-BSA and ¹³¹I-MnO₂-BSA + anti-PD-L1. e, f Tumor weights (e) and representative digital photos (f) of primary and distant dissected tumors harvested from mice after 14 days post-various treatments (G1–G4). g Immunofluorescence images of primary and distant tumor slices stained with anti-CD8 antibody after 14 days post-corresponding treatments in both Control and ¹³¹I-MnO₂-BSA + anti-PD-L1 groups. P values were calculated by ANOVA (***P < 0.001). Data are expressed as mean ± SD (n = 5). G1–G4 represent Control, Anti-PD-L1, ¹³¹I-MnO₂-BSA and ¹³¹I-MnO₂-BSA + Anti-PD-L1, respectively. Dose: 500 µCi