Characterisation of chikungunya virus neutralising monoclonal antibodies expressed in tobacco plants

Chikungunya virus (CHIKV) causes a debilitating musculoskeletal disease, characterised by flu-like symptoms, rash, and severe joint pain, which can last for months, even after the resolution of infection. Although the first CHIKV vaccine was approved in the USA in 2023 for use in adults, there is currently no specific antiviral therapy for infection. While neutralising antibody-based prophylactic and therapeutic agents have been considered, affordability and accessibility are major barriers to global regions where Chikungunya disease is epidemic. Here, we expressed five anti-CHIKV neutralising IgG monoclonal antibodies (mAbs) in N. benthamiana plants to investigate the potential use of this manufacturing platform. Plants produced IgG mAbs that compared favourably to mammalian cell-expressed antibodies, including for binding kinetics to CHIKV antigens and neutralisation activity. The yields of mAbs from plants were variable, as three of the antibodies’ yields would need further expression optimisation to warrant future development. The successful expression of these antibodies in N. benthamiana plants supports the growing pipeline of Global Health product targets that could be developed using a highly transferable, low-cost, low-tech plant production platform in resource-poor countries.