ABSTRACT
Virus-like particles (VLPs) are multimeric, sometimes multiprotein nanostructures assembled from viral structural proteins. They carry no replicative genetic information and can be produced in heterologous expression systems on a large scale. VLPs present repetitive high-density displays of viral surface proteins. Importantly, they contain functional viral proteins responsible for cell penetration of the virus, ensuring efficient cell entry and, thus, tissue-specific targeting characteristic of the virus of origin. The foremost application of VLPs is in vaccinology, where they provide delivery systems that combine good safety profiles with strong immunogenicity and constitute a safe alternative to inactivated infectious viruses. These stable and versatile nanoparticles display excellent adjuvant properties capable of inducing innate and cognate immune responses, resulting in the control of pathogenic microorganisms. Two VLP vaccines are already in use and several others will soon follow. More audacious utilization of VLPs properties is for drug delivery, whereby their vectoring properties are harnessed. In this approach advantage is taken of the remarkably efficient cell entry of VLPs, their repetitive surfaces providing polyvalency, and sometimes their native affinity conceivably ensuring specific targeting. However, such utilization of VLPs is in their infancy and has yet to be implemented in clinics.
