Figure 5.

CD155-deletion overcomes resistance to ICIs in vivo mouse model. (A) CD155 expression in pvr-KO B16F10 cells. Representative flow cytometry staining from triplicated experiments are shown. (B) Tumor growth treated with combination treatment of anti-PD-1 and anti-CTLA-4 mAbs. Cells (1×10⁶) were injected subcutaneously (n=5 per each group), and tumor volume was monitored two times a week. Mice were grouped when the tumor volume reached approximately ~100 mm³, and ICIs were administered intraperitoneally three times every 3 days thereafter. (C and D) The frequencies of CD44⁺CD62L⁻ effector memory, and cytokine-producing CD8⁺ T cells in the tumor microenvironment treated with combination treatment of anti-PD-1 and anti-CTLA-4 mAbs. Tumors were harvested 7 days after treatment initiation to collect tumor-infiltrating lymphocytes for evaluation. Representative flow cytometry staining (C) and summaries (D) are shown. All in vivo experiments were performed in duplicates, with similar results. Two-way analysis of variance with Bonferroni corrections were used in (B), and t-tests were used in (D) for statistical analyses. The means and SEM are shown. ***, p<0.001; ****, p<0.0001; CTLA-4, cytotoxic T-lymphocyte-associated protein 4; ns, not significant; PD-1, programmed death 1.