Annexin A5-engineered nanovaccines synchronize spatiotemporal antigen release with phagocytosis checkpoint blockade for potent in situ cancer immunotherapy.

In situ generation of autologous tumor vaccines from dying tumor cells offers a promising route for personalized cancer immunotherapy, yet is often limited by phosphatidylserine (PS)-mediated immunosuppressive clearance that can restrict downstream immune activation and favor M2-like macrophage polarization. Here, we report a sequentially orchestrated nanovaccine (NT@ANX5-P) that couples photodynamic therapy (PDT)-induced immunogenic tumor-cell damage with on-demand PS masking to enhance in situ tumor vaccination. The nanovaccine consists of a photosensitizer core cloaked with genetically engineered tumor cell membranes displaying Annexin A5 (ANX5) and further shielded by a ROS-cleavable PEG layer for circulatory shielding and local light-responsive activation. Upon localized light irradiation, tumor cells undergo PDT-induced damage and apoptosis, while ROS-triggered PEG cleavage increases ANX5 accessibility for binding exposed PS, thereby attenuating PS-dependent efferocytic clearance and favoring progression toward secondary necrosis. This coordinated treatment enhanced dendritic cell maturation, remodeled tumor-associated macrophage phenotypes, and increased T-cell responses. In 4T1 tumor-bearing mice, NT@ANX5-P suppressed primary and distant tumor growth, reduced lung metastasis, and induced protection against homologous tumor rechallenge. CD8+ T-cell depletion markedly weakened bilateral tumor control, supporting an important functional contribution of CD8+ T cells. These findings provide proof-of-concept for coordinating PDT-induced antigen generation with spatially regulated modulation of PS-dependent dying-cell clearance in the 4T1 model.