Interaction analysis of glycoengineered antibodies with CD16a: a native mass spectrometry approach

• Main Authors: Joanna Hajduk (Author), Cyrill Brunner (Author), Sebastian Malik (Author), Jana Bangerter (Author), Gisbert Schneider (Author), Marco Thomann (Author), Dietmar Reusch (Author), Renato Zenobi (Author)
• Format: Book
• Published: Taylor & Francis Group, 2020-01-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.1080/19420862.2020.1736975; 1942-0870; 1942-0862
• Keywords: Glycoengineering; monoclonal antibody; fc gamma receptor; native mass spectrometry; thermal stability; Therapeutics. Pharmacology; RM1-950; Immunologic diseases. Allergy; RC581-607
• Source: mAbs, Vol 12, Iss 1 (2020)

Minor changes in the quality of biologically manufactured monoclonal antibodies (mAbs) can affect their bioactivity and efficacy. One of the most important variations concerns the N-glycosylation pattern, which directly affects an anti-tumor mechanism called antibody-dependent cell-meditated cytotoxicity (ADCC). Thus, careful engineering of mAbs is expected to enhance both protein-receptor binding and ADCC. The specific aim of this study is to evaluate the influence of terminal carbohydrates within the Fc region on the interaction with the FcγRIIIa/CD16a receptor in native and label-free conditions. The single mAb molecule comprises variants with minimal and maximal galactosylation, as well as α2,3 and α2,6-sialic acid isomers. Here, we apply native electrospray ionization mass spectrometry to determine the solution-phase antibody-receptor equilibria and by using temperature-controlled nanoelectrospray, a thermal stability of the complex is examined. Based on these, we prove that the galactosylation of a fucosylated Fc region increases the binding to CD16a 1.5-fold when compared with the non-galactosylated variant. The α2,6-sialylation has no significant effect on the binding, whereas the α2,3-sialylation decreases it 1.72-fold. In line with expectation, the galactoslylated and α2,6-sialylated mAb:CD16a complex exhibit higher thermal stability when measured in the temperature gradient from 20 to 50°C. The similar binding pattern is observed based on surface plasmon resonance analysis and immunofluorescence staining using natural killer cells. The results of our study provide new insight into N-glycosylation-based interaction of the mAb:CD16a complex.