Antigen-functionalized turnip mosaic virus nanoparticles increase antibody sensing in saliva. A case study with SARS-CoV-2 RBD

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Nanoparticles derived from plant viruses play an important role in nanomedicine due to their biocompatibility, self-assembly and easily-modifiable surface. In this study, we developed a novel platform for increasing antibody sensing using viral nanoparticles derived from turnip mosaic virus (TuMV) functionalized with SARS-CoV-2 receptor binding domain (RBD) through three different methods: chemical conjugation, gene fusion and the SpyTag/SpyCatcher technology. Even though gene fusion turned out to be unsuccessful, the other two constructs were proven to significantly increase antibody sensing when tested with saliva of patients with different infection and vaccination status to SARS-CoV-2. Our findings show the high potential of TuMV nanoparticles in the fields of diagnostics and immunodetection, being especially attractive for the development of novel antibody sensing devices.

This work was mostly funded by grant COV20/00114 from Comunidad de Madrid to FP. We want to particularly acknowledge the donors and the Biobank Biobanco Hospital Universitario de La Princesa (Madrid) (ISCIII B.0000763) for their collaboration. We also thank Agrenvec S.L (Tres Cantos, Madrid, Spain) for the generous gift of its plant-made RBD. DAT was supported by a Margarita Salas postdoctoral grant funded by the Spanish Ministry of Universities and UCM (CT31/21). SR was funded by a contract under grant P2018/BAA-4574 from the Comunidad de Madrid. This work was part of the Final Grade Thesis of CM for graduation in biotechnology by the UPM. The CBGP was granted ‘Severo Ochoa’ Distinctions of Excellence by the Spanish Ministry of Science and Innovation (SEV- 2016-0672 and CEX2020-000999-S).

With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2020‐000999‐S)

Peer reviewed