Phytochemical Engineered Bacterial Outer Membrane Vesicles for Photodynamic Effects Promoted Immunotherapy

Area of Science:

• Biotechnology
• Immunology
• Materials Science

Background:

• Cancer vaccines are a promising immunotherapy, but face challenges in fabrication and efficacy.
• Current methods often struggle with targeting and stimulating robust anti-tumor immune responses.

Purpose of the Study:

• To develop a novel *in situ* cancer vaccine using bacterial outer membrane vesicles (OMVs) combined with plant-derived thylakoid membranes.
• To leverage photodynamic effects for enhanced tumor immunotherapy and immune cell activation.
• To create a versatile hybrid system for effective tumor treatment.

Main Methods:

• Fabrication of bacteria-plant hybrid vesicles (BPNs) by fusing thylakoid membranes with OMVs.
• Systemic administration of BPNs to target tumor tissues.
• Utilizing photodynamic effects from thylakoids to disrupt tumors and release antigens.
• Assessing immune cell activation, particularly dendritic cells (DCs) and CD8+ T cell responses.
• Evaluating the modulation of the tumor microenvironment.

Main Results:

• BPNs successfully targeted tumor tissues and activated immune cells like DCs.
• Photodynamic effects promoted tumor disruption and antigen release.
• Enhanced presentation of tumor-associated antigens by DCs led to significant CD8+ T cell responses.
• The immunosuppressive tumor microenvironment was ameliorated, boosting overall immune responses.
• Tumor development and metastasis were effectively inhibited.

Conclusions:

• The developed BPNs serve as an effective *in situ* cancer vaccine.
• This hybrid vesicle system offers a novel strategy for photodynamic effects-promoted immunotherapy.
• The approach shows potential for highly efficient tumor treatment by boosting anti-tumor immunity.