Phytochemical Engineered Bacterial Outer Membrane Vesicles for Photodynamic Effects Promoted Immunotherapy.

Abstract

Cancer vaccines are emerging as an attractive modality for tumor immunotherapy. However, their practical application is seriously impeded by the complex fabrication and unsatisfactory outcomes. Herein, we construct bacterial outer membrane vesicles (OMVs)-based <i>in situ</i> cancer vaccine with phytochemical features for photodynamic effects-promoted immunotherapy. By simply fusing thylakoid membranes with OMVs, bacteria-plant hybrid vesicles (BPNs) are prepared. After systemic administration, BPNs can target tumor tissues and stimulate the activation of immune cells, including dendritic cells (DCs). The photodynamic effects derived from thylakoid lead to the disruption of local tumors and then the release of tumor-associated antigens that are effectively presented by DCs, inducing remarkable tumor-specific CD8⁺T cell responses. Moreover, BPNs can efficiently ameliorate the immunosuppressive tumor microenvironment and further boost immune responses. Therefore, both tumor development and metastasis can be efficiently prevented. This work provides a novel idea for developing a versatile membrane-based hybrid system for highly efficient tumor treatment.