Engineering the interactions between a plant‐produced HIV antibody and human Fc receptors

Szymon Stelter (1) , Mathew J Paul (1) , Audreey Y.-H Teh (1) , Melanie Grandits (1) , Friedrich Altmann (2) , Jessica Vanier (3) , Muriel Bardor (3, 4) , Alexandra Castilho (2) , Rachel Louise Allen (2) , Julian K-C Ma (1)

1 St George's, University of London
2 BOKU - Universität für Bodenkultur Wien = University of Natural Resources and Life [Vienne, Autriche]
3 Glyco-MEV - Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale
4 IUF - Institut Universitaire de France

Plants can provide a cost-effective and scalable technology for production of therapeutic monoclonal antibodies, with the potential for precise engineering of glycosylation. Glycan structures in the antibody Fc region influence binding properties to Fc receptors, which opens opportunities for modulation of antibody effector functions. To test the impact of glycosylation in detail, on binding to human Fc receptors, different glycovariants of VRC01, a broadly neutralizing HIV monoclonal antibody, were generated in Nicotiana benthamiana and characterized. These include glycovariants lacking plant characteristic a1,3-fucose and b1,2-xylose residues and glycans extended with terminal b1,4-galactose. Surface plasmon resonance-based assays were established for kinetic/affinity evaluation of antibody-FccR interactions, and revealed that antibodies with typical plant glycosylation have a limited capacity to engage FccRI, FccRIIa, FccRIIb and FccRIIIa; however, the binding characteristics can be restored and even improved with targeted glycoengineering. All plant-made glycovariants had a slightly reduced affinity to the neonatal Fc receptor (FcRn) compared with HEK cell-derived antibody. However, this was independent of plant glycosylation, but related to the oxidation status of two methionine residues in the Fc region. This points towards a need for process optimization to control oxidation levels and improve the quality of plant-produced antibodies.

Keywords: antibody; glycoengineering; plant; molecular pharming; Fc receptor; fucose; CD16; CD64; FcRn; neonatal Fc receptor; methionine oxidation

Domains: Vegetal Biology; Biotechnology; Genomics [q-bio.GN]; Phytopathology and phytopharmacy; Plant breeding; Molecular biology; Cellular Biology; Biochemistry [q-bio.BM]; Development Biology; Cell Behavior [q-bio.CB]; Subcellular Processes [q-bio.SC]

Szymon Stelter, Mathew J Paul, Audreey Y.-H Teh, Melanie Grandits, Friedrich Altmann, et al.. Engineering the interactions between a plant‐produced HIV antibody and human Fc receptors. Plant Biotechnology Journal, 2020, 18, pp.402-414. ⟨10.1111/pbi.13207⟩. ⟨hal-02276812⟩