Alpha-alumina nanoparticles induce efficient autophagy-dependent cross-presentation and potent antitumour response

Therapeutic cancer vaccination is an attractive immune therapy strategy to actively induce T cells that specifically recognize and kill tumour cells in cancer patients. However, it remains difficult to generate a large number antigen-specific T cells using conventional vaccine carrier systems(1,2). Here we show that α-Al(2)O(3) nanoparticles can act as an antigen carrier to reduce the amount of antigen required by dendritic cells to activate T cells in vitro and in vivo. We found that α- Al(2)O(3) nanoparticles delivered antigens to autophagosomes in dendritic cells (DCs), which then presented the antigens to T cells through autophagy – the normal degradation process of cell components in cells. Immunization of mice with α-Al(2)O(3) nanoparticles that are conjugated to either a model tumour antigen or autophagosomes derived from tumour cells resulted in tumour regression. These results suggest that α-Al(2)O(3) nanoparticles may be a promising adjuvant in the development of therapeutic cancer vaccines.