ABSTRACT
Plant viruses and their virus-like particles (VLPs) have a lot of advantages for biotechnological applications including complete safety for humans. Alternanthera mosaic virus (AltMV) is a potentially promising object for design of novel materials. The 3D structures of AltMV virions and its VLPs were obtained by single particle EM at ~13Å resolution. The comparison of the reconstructions and a trypsin treatment revealed that AltMV CPs possesses a different fold in the presence (virions) and absence of viral RNA (VLPs). For the first time, the structure of morphologically similar virions and virus-like particles based on the coat protein of a helical filamentous plant virus is shown to be different. Despite this, both AltMV virions and VLPs are stable in a wide range of conditions. To provide a large amount of AltMV for biotechnology usage the isolation procedure was modified.
Subject(s)
Capsid Proteins/chemistry , Mosaic Viruses/chemistry , Virion/chemistry , Microscopy, Electron/methodsABSTRACT
A novel rubella candidate vaccine based on a structurally modified plant virus - spherical particles (SPs) - was developed. SPs generated by the thermal remodelling of the tobacco mosaic virus are promising platforms for the development of vaccines. SPs combine unique properties: biosafety, stability, high immunogenicity and the effective adsorption of antigens. We assembled in vitro and characterised complexes (candidate vaccine) based on SPs and the rubella virus recombinant antigen. The candidate vaccine induced a strong humoral immune response against rubella. The IgG isotypes ratio indicated the predominance of IgG1 which plays a key role in immunity to natural rubella infection. The immune response was generally directed against the rubella antigen within the complexes. We suggest that SPs can act as a platform (depot) for the rubella antigen, enhancing specific immune response. Our results demonstrate that SPs-antigen complexes can be an effective and safe candidate vaccine against rubella.
