A Dual Role of Type I Interferons in Antitumor Immunity

Abstract Type I interferons (IFN‐Is) are a family of cytokines that exert direct antiviral effects and regulate innate and adaptive immune responses through direct and indirect mechanisms. It is generally believed that IFN‐Is repress tumor development via restricting tumor proliferation and inducing antitumor immune responses. However, recent emerging evidence suggests that IFN‐Is play a dual role in antitumor immunity. That is, in the early stage of tumorigenesis, IFN‐Is promote the antitumor immune response by enhancing antigen presentation in antigen‐presenting cells and activating CD8 + T cells. However, in the late stage of tumor progression, persistent expression of IFN‐Is induces the expression of immunosuppressive factors (PD‐L1, IDO, and IL‐10) on the surface of dendritic cells and other bone marrow cells and inhibits their antitumor immunity. This review outlines these dual functions of IFN‐Is in antitumor immunity and elucidates the involved mechanisms, as well as their applications in tumor therapy.