Figure 7.

Effect of IL-6 blockade combined with anti-PD-1 therapy in melanoma-bearing mice. RET transgenic mice with established tumors were injected intraperitoneally with anti-IL-6 blocking antibodies or with anti-PD-1 therapeutic antibodies for 4 weeks, twice per week. Some mice received both anti-IL-6 and anti-PD-1 antibodies. Control group of mice was treated with isotype control antibodies. (A) Survival of mice is shown as a Kaplan-Meier curve (n=15/group). **p<0.01. In another set of experiments, tumor weight was measured, and immune cells were analyzed by flow cytometry after 4 weeks of therapy. Results are presented as the weight of tumors in mg (mean±SD; n=4–7) (B), as the percentage of CD11b⁺Gr1⁺ MDSC within leukocytes (C), the MFI of ROS producing MDSC (D) and the percentage of CD8⁺ T cells within leukocytes (E) (mean±SD, n=3–8). MDSC, myeloid-derived suppressor cells; MFI, median fluorescence intensity; ROS, reactive oxygen species.