Nitrated T cell epitope linked vaccine targeting CD47 elicits antitumor immune responses and acts synergistically with vaccine targeting PDL1

Despite the clinical breakthrough made by immune checkpoint blockades (ICB) in cancer immunotherapy, immunosuppressed tumor microenvironment (TME) remains a major impediment in the efficacy of ICB immunotherapy. In this study, we constructed a Nitrated T cell epitope (NitraTh) linked vaccine targeting CD47, namely CD47-NitraTh. CD47-NitraTh could repress the progression of tumor by inducing tumor-specific immune response. Furthermore, combination vaccination with CD47-NitraTh and PDL1-NitraTh could reconstruct tumor associated macrophage, enhance macrophage-mediated phagocytosis for tumor cells, and promote the activation of tumor infiltrating T cells. Notably, by activating chemokine signaling pathway, NitraTh based vaccines reversed immunosuppressed TME, resulting in improved therapeutic outcome for tumor. With the advantage of reversing immunosuppressed TME, NitraTh based vaccine seems an optimal immunotherapy strategy for patients who are not sensitive to antibody based ICB.