From Virus-like Particles to Engineered Exosomes for a New Generation of Vaccines

Abstract

Over the last two decades, virus-like particles (VLPs) have been the focus of countless investigations on innovative vaccines. The number of monotypic, multipartite and chimeric VLP-based vaccines proposed have increased even further in the last few years as part of the continuous effort to improve the safety, efficacy and cost–effectiveness of immunogens. As compared with monomer- or subunit-based vaccines, VLPs show several advantages in terms of potency of the elicited immune responses. Chimeric VLPs are quite flexible tools to accommodate foreign peptides, cell proteins and nonself-assembling viral products. However, their use often meets with still unresolved hurdles such as induction of undesired immune responses, neutralization by pre-existing immunity and complex methods of production. Among strategies aimed at developing new nanoparticle-based vaccines, exosomes hold much promise. They are nanovesicles constitutively released by eukaryotic cells that originate from intraluminal vesicles accumulating in multivesicular bodies. Exosomes have immunogenic properties, the strength of which correlates with the amounts of associated antigens. Engineering antigens of interest to target them in exosomes represents the last frontier in terms of nanoparticle-based vaccines.

Keywords:

• antigen delivery
• CTL immunity
• exosome
• lentivirus
• Nef
• vaccine
• virus-like particle

Acknowledgement

The author is indebted to G Fornari-Luswergh (National AIDS Center, Istituto Superiore di Sanità, Rome, Italy) for the excellent editorial assistance.

Financial & competing interests disclosure

This work was supported by grants (3H/27, 3H/28 and 3H/29) from the National AIDS Program from the Italian Ministry of Health, Rome, Italy. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Additional information

Funding

This work was supported by grants (3H/27, 3H/28 and 3H/29) from the National AIDS Program from the Italian Ministry of Health, Rome, Italy. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.