A Modular Antigen Presenting Peptide/Oligonucleotide Nanostructure Platform for Inducing Potent Immune Response

The design and development of vaccines, which can induce cellular immunity, particularly CD8+ T cells hold great importance since these cells play crucial roles against cancers and viral infections. Covalent conjugation of antigen and adjuvant molecules has been used for successful promotion of immunogenicity in subunit vaccines; however, the stimulation of the CD8+ T-cell responses by this approach has so far been limited. This study demonstrates a modular system based on noncovalent attachment of biotinylated antigen to a hybrid nanofiber system consisting of biotinylated self-assembling peptide and CpG oligodeoxynucleotides (ODN) molecules, via biotin-streptavidin interaction. These peptide/oligonucleotide hybrid nanosystems are capable of bypassing prior limitations related with inactivated or live-attenuated virus vaccines and achieve exceptionally high CD8+ T-cell responses. The nanostructures are found to trigger strong IgG response and effectively modulate cross-presentation of their antigen "cargo" through close proximity between the antigen and peptide/ODN adjuvant system. In addition, the biotinylated peptide nanofiber system is able to enhance antigen uptake and induce the maturation of antigen-presenting cells. Due to its versatility, biocompatibility, and biodegradability with a broad variety of streptavidin-linked antigens, the nanosystem shown here can be utilized as an efficient strategy for new vaccine development.