Advances and challenges in enveloped virus-like particle (VLP)-based vaccines

Virus-like particles (VLPs) are highly organized particles that self-assemble from viral structural proteins.Like parental viruses, VLPs can be either non-enveloped or enveloped and can be produced in different expression systems depending on their complexity.Over the last three decades, VLPs have developed as a high-priority alternative to traditional vaccines against infectious pathogens due to their safety, simplicity and favorable immunological characteristics to induce both humoral and cellular immune responses.Most of emerging and re-emerging viruses that pose a continuous threat to human health are enveloped, but few vaccines are currently available.Advances in expression technology for complex, enveloped VLPs provide new possibilities to develop potent vaccines against pathogenic enveloped viruses.This review describes major progress and challenges in the production of enveloped VLPs, with respect to the main principles in the assembly and budding process, factors that need to be taken into account for the design strategies and choice of relevant production platforms.