Immunotherapy is a type of anti-tumor treatment and has shown great clinical success against a wide variety of malignancies in recent years. Poly(I : C), a TLR3 agonist, is the most potent type I interferon (IFN) inducer. Poly(I : C) not only directly induces tumorous apoptosis, but also stimulates tumor cells to secrete immune factors. However, the immune response rate induced by Poly(I : C) remains low in several types of malignancies and higher doses are often required to achieve the desired effect. However, poly(I : C) is highly toxic and thus only a very narrow therapeutic window is available, which greatly limits clinical application of Poly(I : C)-based treatments.