Self-Assembled Proteinaceous Nanoparticles for Co-Delivery of Antigens and Cytosine Phosphoguanine (CpG) Adjuvants: Implications for Nanovaccines

Nanotechnology has developed rapidly, giving rise to “nanovaccinology”. In particular, protein-based nanocarriers have gained widespread attention because of their excellent biocompatibility. As the development of flexible and rapid vaccines is challenging, modular extensible nanoparticles are urgently needed. In this study, a multifunctional nanocarrier capable of delivering various biomolecules (including polysaccharides, proteins, and nucleic acids) was designed by fusing the cholera toxin B subunit with streptavidin. Then, the nanocarrier was used to prepare a bioconjugate nanovaccine against S. flexneri by co-delivery of antigens and CpG adjuvants. Subsequent experimental results indicated that the nanovaccine with multiple components could stimulate both adaptive and innate immunity. Moreover, combining nanocarriers and CpG adjuvants with glycan antigens could improve the survival of vaccinated mice during the interval of two vaccination injections. The multifunctional nanocarrier and the design strategy demonstrated in this study could be utilized in the development of many other nanovaccines against infectious diseases.