Ferritin nanocage-based antigen delivery nanoplatforms: epitope engineering for peptide vaccine design.

Biomedical applications and nanotechnological advances, including constrained synthesis, multimodal imaging, drug delivery, and bioassay, have strongly benefited from employing ferritin nanocages due to their remarkable properties of easy engineering, great biocompatible features, large capacity and so on. In this study, ferritin nanocages were used to display epitopes (model antigens derived from Enterovirus 71 (EV71) with different length) on C- and N-terminals and the loop zone to search for the optimal position for the fusion of the epitopes to the vaccine platform. The longest epitope displayed on the N-terminal and loop zone as well as the second longest peptide displayed on the loop zone of ferritin resulted in 100% passive protection of newborn BALB/c mice from the lethal EV71. This suggests that peptides fused onto the loop zone of ferritin could induce strong immune response. Our results increase the versatility of the vaccine platform and provide more options for the production of stable constructs, suggesting the potential future clinical applicability of ferritin-based antigen delivery nanoplatforms.