Expression of IFNγR^DN in tumor cells overcomes the inhibitory effects of IFNγ. (A) Expression levels of IFNγR1, MHC-I (H-2K^b and H-2D^b), MHC-II (I-A^b), and PD-L1 on B16 and 2 stable B16 clones expressing high or low levels of a IFNγR^DN receptor. B16, B16-IFNγR^DN/Hi, and B16-IFNγR^DN/Lo cells were incubated (IFNγ) or not (No Tx) with 100 U/mL of IFNγ for 40 hours, and stained with specific antibodies as indicated, followed by flow-cytometry analysis. (B) Freshly isolated and purified CD8 T cells from Trp1₄₅₅TriVax or Trp2₁₈₀TriVax-immunized WT mice (as indicated) were tested for cytolytic activity against several target cells treated (IFNγ) and nontreated (No Tx) with IFNγ (100 U/mL, 24 hours): Parental B16 and 2 stable B16 clones expressing high (B16-IFNγR^DN/Hi) or low (B16-IFNγR^DN/Lo) levels of IFNγR^DN. (C) Therapeutic effects induced by Trp2₁₈₀TriVax in WT mice against 7-day-established subcutaneous B16 tumors expressing or not IFNγR^DN. P value (2-way ANOVA) compares Trp2₁₈₀TriVax-immunized mice bearing B16-IFNγR^DN/Hi with Trp2₁₈₀TriVax-immunized mice bearing B16. *50% of the Trp2₁₈₀TriVax-immunized mice bearing B16-IFNγR^DN/Hi rejected their tumors. These experiments were repeated twice with similar results.