Disclosed are nanoparticle-autophagosome conjugates capable of stimulating an immune response against a target antigen, wherein the nanoparticle-autophagosome conjugates include autophagosome(s) covalently attached to alumina nanoparticle(s), wherein the autophagosome includes defective ribosomal products (DRiPs) of the target antigen. Also disclosed are immunogenic compositions including these conjugates and/or antigen-presenting cells loaded with these conjugates, and methods of stimulating an immune response against a target antigen by administration of immunogenic compositions including these conjugates and/or antigen-presenting cells loaded with these conjugates.
