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Production of two SARS-CoV-2 neutralizing antibodies with different potencies in Nicotiana benthamiana

TitleProduction of two SARS-CoV-2 neutralizing antibodies with different potencies in Nicotiana benthamiana
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2022
AuthorsFrigerio, R., Marusic Carla, Villani Maria Elena, Lico Chiara, Capodicasa Cristina, Andreano E., Paciello I., Rappuoli R., Salzano A.M., Scaloni A., Baschieri Selene, and Donini Marcello
JournalFrontiers in Plant Science

Monoclonal antibodies are considered to be highly effective therapeutic tools for the treatment of mild to moderate COVID-19 patients. In the present work, we describe the production of two SARS-CoV-2 human IgG1 monoclonal antibodies recognizing the spike protein receptor-binding domain (RBD) and endowed with neutralizing activity (nAbs) in plants. The first one, mAbJ08-MUT, was previously isolated from a COVID-19 convalescent patient and Fc-engineered to prolong the half-life and reduce the risk of antibody-dependent enhancement. This nAb produced in mammalian cells, delivered in a single intramuscular administration during a Phase I clinical study, was shown to (i) be safe and effectively protect against major variants of concern, and (ii) have some neutralizing activity against the recently emerged omicron variant in a cytopathic-effect-based microneutralization assay (100% inhibitory concentration, IC100 of 15 μg/mL). The second antibody, mAb675, previously isolated from a vaccinated individual, showed an intermediate neutralization activity against SARS-CoV-2 variants. Different accumulation levels of mAbJ08-MUT and mAb675 were observed after transient agroinfiltration in Nicotiana benthamiana plants knocked-out for xylosil and fucosil transferases, leading to yields of 35 and 150 mg/kg of fresh leaf mass, respectively. After purification, as a result of the proteolytic events affecting the hinge-CH2 region, a higher degradation of mAb675 was observed, compared to mAbJ08-MUT ( 18% vs. 1%, respectively). Both nAbs showed a human-like glycosylation profile, and were able to specifically bind to RBD and compete with angiotensin-converting enzyme 2 binding in vitro. SARS-CoV-2 neutralization assay against the original virus isolated in Wuhan demonstrated the high neutralization potency of the plant-produced mAbJ08-MUT, with levels (IC100 < 17 ng/mL) comparable to those of the cognate antibody produced in a Chinese hamster ovary cell line; conversely, mAb675 exhibited a medium neutralization potency (IC100 200 ng/mL). All these data confirm that plant expression platforms may represent a convenient and rapid production system of potent nAbs to be used both in therapy and diagnostics in pandemic emergencies. Copyright © 2022 Frigerio, Marusic, Villani, Lico, Capodicasa, Andreano, Paciello, Rappuoli, Salzano, Scaloni, Baschieri and Donini.


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Citation KeyFrigerio2022