Virus-like particles: preparation, immunogenicity and their roles as nanovaccines and drug nanocarriers

Abstract

Virus-like particles (VLPs) are virus-derived structures made up of one or more different molecules with the ability to self-assemble, mimicking the form and size of a virus particle but lacking the genetic material so they are not capable of infecting the host cell. Expression and self-assembly of the viral structural proteins can take place in various living or cell-free expression systems after which the viral structures can be assembled and reconstructed. VLPs are gaining in popularity in the field of preventive medicine and to date, a wide range of VLP-based candidate vaccines have been developed for immunization against various infectious agents, the latest of which is the vaccine against SARS-CoV-2, the efficacy of which is being evaluated. VLPs are highly immunogenic and are able to elicit both the antibody- and cell-mediated immune responses by pathways different from those elicited by conventional inactivated viral vaccines. However, there are still many challenges to this surface display system that need to be addressed in the future. VLPs that are classified as subunit vaccines are subdivided into enveloped and non- enveloped subtypes both of which are discussed in this review article. VLPs have also recently received attention for their successful applications in targeted drug delivery and for use in gene therapy. The development of more effective and targeted forms of VLP by modification of the surface of the particles in such a way that they can be introduced into specific cells or tissues or increase their half-life in the host is likely to expand their use in the future. Recent advances in the production and fabrication of VLPs including the exploration of different types of expression systems for their development, as well as their applications as vaccines in the prevention of infectious diseases and cancers resulting from their interaction with, and mechanism of activation of, the humoral and cellular immune systems are discussed in this review.

Influenza Virus-like Particle (VLP) Vaccines Expressing the SARS-CoV-2 S Glycoprotein, S1, or S2 Domains

“…Reportedly, T cell exhaustion and extremely low levels of peripheral T cells were common features observed in COVID-19 patients [ 34 ]. Given the nature of VLPs, which are capable of inducing both humoral and cellular immune responses [ 35 ], robust expansion of immune cells associated with cellular immunity could be expected from the VLP vaccines presented here.…”

Peptide-guided JC polyomavirus-like particles specifically target bladder cancer cells for gene therapy

“…Therefore, JCPyV VLPs can be guided by a cell surface marker binding peptide for the specific delivery and transduction of a gene of interest expressed by a tissue-specific promoter in a targeted cell type. VLPs retain the characteristics of virus-specific binding to host cells, but are allowed for genetic or chemical modification to alter the tropism or increase their binding efficiency to their nature host cells 33 , 34 . For example, the specific cellular targeting of MS2 VLPs are demonstrated through attachment of a tissue specific nucleic acid aptamers 35 .…”

Differential enrichment of yeast DNA in SARS-CoV-2 and related genomes supports synthetic origin hypothesis

“…Rz, self-cleaving ribozyme. M (membrane), and N (nucleocapsid) that can be used in parallel by an extended set of auxiliary proteins, Aux* 29 . This hypothetical cellular factory may therefore produce the targeted, fully infectious viral particles without itself being infected by the virus produced.…”