Study of rubella candidate vaccine based on a structurally modified plant virus

•In vitro assembly and characterisation of a rubella candidate vaccine based on modified plant virus (spherical particles).•Candidate vaccine induces efficient humoral immune response against rubella.•Acute and chronic toxicity studies demonstrate biosafety of candidate vaccine.•Candidate vaccine demonstrated good results and can be considered as a promising safe tool against the rubella virus.

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.

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