Autophagy-activating aluminum hydroxide nanovaccine for enhanced antigen presentation and anti-tumor immunity.

Lymph node (LN) targeting and antigen presentation by antigen-presenting cells (APCs) are critical factors affecting the immune responses induced by tumor vaccines. Autophagy activation promotes MHC class I and II antigen presentation in APCs. To enhance antigen presentation in LNs, we developed an aluminum hydroxide nanovaccine that simultaneously incorporates the autophagy-activating peptide Beclin-1 and the antigenic protein OVA (B/O@AN nanovaccine) through layer-by-layer electrostatic interaction. B/O@AN has a particle size of approximately 80 nm and efficiently targets lymph nodes following subcutaneous administration. The combination of the Beclin-1 peptide with the aluminum hydroxide nanovaccine promotes dendritic cell (DC) maturation. More importantly, B/O@AN facilitates antigen cross-presentation by promoting lysosomal escape and autophagy induction. After immunization, compared to O/@AN without Beclin-1, B/O@AN significantly augments antigen-specific cellular immune responses, leading to substantial increases in cytotoxic T lymphocytes (CTLs), T-helper 1 (Th1) cells, as well as serum antibody levels, thereby impeding melanoma development and progression in both prophylactic and therapeutic settings. These results provide evidence that autophagy activation strengthens antigen presentation and augments the antigen-specific immune responses of the aluminum hydroxide nanovaccine.