Fig. 4

The expressions of PD-L1 and PD-L2 in osteosarcoma cell lines and nivolumab-suppressed osteosarcoma metastasis in vivo. a Western blotting analyses of PD-L1 and PD-L2 expression. NIH3T3 was used as the positive control. b Representative membranous expression of PD-L1 and PD-L2 in the KHOS cell line (red) compared with that of the isotype control (black) from the flow cytometry analysis. c The tumor growth curve of the nivolumab-treated and control groups. d Representative images of the primary tumors. e Metastatic frequency of the nivolumab-treated and control groups. f The number of metastatic nodules in the lungs from the nivolumab-treated and control groups is presented. g H&E staining of the lungs from the nivolumab-treated and control groups (magnification at × 16 and × 100). The lung metastases are indicated by the arrows. Data are presented as the mean ± S.D. (n = 5) ***P < 0.001 by Student’s t test