Fig. 4

OVs combined with ICIs are complementary to each other. OVs infecting tumor cells attract many APCs to the tumor injection site, stimulating CD8⁺ T production and increasing the infiltration of CD8⁺ T cells in the tumor microenvironment, transforming a "cold" tumor into a "hot" tumor. The effect of OVs stimulates the expression of PD-L1 on the surface of tumor cells, and ICIs can block the binding of PD-L1 and PD-1, thus relieving the immunosuppressive effect. The ICIs can enhance the anti-tumor immune response triggered by OVs. Therefore, local injection of OVs to activate the systemic anti-tumor immune response increases the infiltration of CD8⁺ T cells and promotes the expression of PD-L1, followed by the administration of ICIs to enhance the therapeutic effect