Glyco-engineered pentameric SARS-CoV-2 IgMs show superior activities compared to IgG1 orthologues

Abstract

Immunoglobulin M (IgM) is the largest antibody isotype with unique features like extensive glycosylation and oligomerization. Major hurdles in characterizing its properties are difficulties in the production of well-defined multimers. Here we report the expression of two SARS-CoV-2 neutralizing monoclonal antibodies in glycoengineered plants. Isotype switch from IgG1 to IgM resulted in the production of pentameric IgMs, comprising of correctly assembled 21 human protein subunits. All four recombinant monoclonal antibodies carried a highly reproducible human-type N-glycosylation profile, with a single dominant N-glycan species at each glycosite. Both pentameric IgMs exhibited increased antigen binding and virus neutralization potency, up to 390-fold, compared to the parental IgG1. Collectively, the results may impact on the future design of vaccines, diagnostics and antibody-based therapies and emphasize the versatile use of plants for the expression of highly complex human proteins with targeted posttranslational modifications.

A genome‐edited N. benthamiana line for industrial‐scale production of recombinant glycoproteins with targeted N‐glycosylation

“…[ 2 ] Nicotiana benthamiana plants are highly suited for transient expression and, as previously demonstrated, can produce monoclonal antibodies in multimeric formats. [ 3–6 ] These proteins are usually heavily glycosylated with significant impacts of this central post‐translational modification on biochemical and functional features. [ 7 ] Therefore, controlling glycosylation is an important quality parameter in recombinant protein production.…”