Fig. 7

Blockade of the IFN-α/β and TNF-α pathways reduces the efficacy of anti-PD-1 therapy. a, b CD45⁺ leukocytes from the tumor tissue of MC38 mice were isolated to detect the MDSC number (left) and Annexin V expression (right). The control animals received 100 μg of isotype control antibody, and the experimental group was treated with 100 μg of PD-1 blockade antibody twice a week for 2 weeks (a). Tumor-infiltrating myeloid suppressors were further purified using CD11b microbeads and cocultured with CFSE-labeled splenocytes for 3 days in the presence of anti-CD3 (2.5 μg/mL) and anti-CD28 (5 μg/mL) antibodies. The proliferation of splenocytes was determined using FACS (b). c Mean tumor volumes of subcutaneous MC38 tumors in mice treated with control (100 μg) or PD-1 mAb (100 μg) in combination with anti-IFNAR1 mAb (100 μg) and anti-TNFR mAb (100 μg) twice a week for 2 weeks. d Frequencies of tumor-infiltrating MDSCs and Annexin V⁺ MDSCs from the tumor tissues described in c. e, f The expression of ARG-1 (e) and the suppressive ability (f) of MDSCs in tumor tissues from control and anti-PD-1-treated mice, in combination with anti-IFNAR1 and anti-TNFR therapy, were detected. Scale bar = 50 μm. g, h The percentages of CD3⁺, CD8⁺, and CD4⁺ T cells determined using FACS (g) and the number of granzyme B⁺ cells examined using IHC (h) in tumor tissues from the indicated groups are summarized. Scale bar = 50 μm. For the data in b, f, n = 3; for the data in a, e, h, n = 7; and for the data in c, d, g, n = 8. The data are from two independent experiments. The data are shown as the mean ± SEM. *p < 0.05; **p < 0.01; ***p < 0.001