Use of plant viruses and virus-like particles for the creation of novel vaccines

In recent decades, the development of plant virology and genetic engineering techniques has resulted in the construction of plant virus-based vaccines for protection against different infectious agents, cancers and autoimmune diseases in both humans and animals. Interaction studies between plant viruses and mammalian organisms have suggested that plant viruses and virus-like particles (VLPs) are safe and noninfectious to humans and animals. Plant viruses with introduced antigens are powerful vaccine components due to their strongly organized, repetitive spatial structure; they can elicit strong immune responses similar to those observed with infectious mammalian viruses. The analysis of published data demonstrated that at least 73 experimental vaccines, including 61 prophylactic and 12 therapeutic vaccines, have been constructed using plant viruses as a carrier structure for presentation of different antigens. This information clearly demonstrates that noninfectious viruses are also applicable as vaccine carriers. Moreover, several plant viruses have been used for platform development, and corresponding vaccines are currently being tested in human and veterinary clinical trials. This review therefore discusses the main principles of plant VLP vaccine construction, emphasizing the physical, chemical, genetic and immunological aspects. Results of the latest studies suggest that several plant virus-based vaccines will join the list of approved human and animal vaccines in the near future.

Protein Complexes and Virus-Like Particle Technology

Virus-like particle (VLP) technologies are based on virus-inspired artificial structures and the intrinsic ability of viral proteins to self-assemble at controlled conditions. Therefore, the basic knowledge about the mechanisms of viral particle formation is highly important for designing of industrial applications. As an alternative to genetic and chemical processes, different physical methods are frequently used for VLP construction, including well characterized protein complexes for introduction of foreign molecules in VLP structures.This chapter shortly discusses the mechanisms how the viruses form their perfectly ordered structures as well as the principles and most interesting application examples, how to exploit the structural and assembly/disassembly properties of viral structures for creation of new nanomaterials.

Isolation and Characterization of Two Distinct Types of Unmodified Spherical Plant Sobemovirus-Like Particles for Diagnostic and Technical Uses

Plant virus-like particles (VLPs) structurally resemble their progenitor viruses, but are noninfectious due to absence of viral nucleic acids. Since the 1980s, VLPs have been actively studied with the aim of constructing different nanomaterials, including immunologically active carriers for peptides and whole proteins and proteinaceous shells for the packaging of different ligands.The technological developments using VLPs require large amounts of purified particles. Here, we describe the laboratory process for isolation and purification of two unmodified plant VLPs, derived from two sobemoviruses, cocksfoot mottle virus (CfMV) and rice yellow mottle virus (RYMV), which is based on cultivation of recombinant Escherichia coli cells, VLP precipitation from bacterial extracts and ultracentrifugation. The suggested purification scheme allows the production of 4-45 mg of purified sobemoviral VLPs from a 1 l bacterial culture, depending on the required purity level. Additionally, we provide short protocols for VLP characterization using SDS-PAGE, agarose gel electrophoresis, ultraviolet and mass spectrometry, dynamic light scattering, and electron microscopy.