Polymer-peptide hybrids as a highly immunogenic single-dose nanovaccine

Aim: To explore four-arm star poly(t-butyl)acrylate (P^tBA)- peptide and linear P^tBA-peptide conjugates as a vaccine-delivery system against Group A Streptococcus. Materials & methods: P^tBA nanoparticles bearing J14 peptide epitopes were prepared via alkyne-azide 1,3-dipolar cycloaddition 'click reaction. The conjugated products were self-assembled into small or large nanoparticles. These nanoparticle vaccine candidates were evaluated in vivo and J14-specific antibody titers were assessed. Results & discussion: Mice vaccinated with the nanoparticles were able to produce J14-specific IgG antibodies without the use of an external adjuvant after a single immunization. We have demonstrated for the first time that the immune responses against self-assembled P^tBA nanoparticles are stronger for the smaller sized (̃20 nm) nanoparticles compared with the larger (̃500nm) P^tBA nanoparticles. Conclusion: PtBA analogs have the potential to be developed as potent carrier systems for single-dose synthetic vaccines.