Deconvolution Reveals the Activity of Specific Glycan Forms

The ability of Fcγ receptors to bind antibodies and induce responses such as antibody-dependent cellular cytotoxicity (ADCC) can impact disease outcomes. FcγR binding is known to be regulated by modification of glycans located in the Fc domain of IgG, although the influence of specific glycans on binding and subsequent activation remains relatively unknown. Glycan-engineering has been previously used to study the effects of different glycans on Fc-mediated responses, but even extensive glycan-engineering methods are limited in their ability to create antibodies expressing a single, pure glycan. In this paper, we apply deconvolution to identify the contributions of individual glycans to FcγR binding and ADCC. Deconvolution revealed that afucosylated glycans are associated with increased ADCC activity and increased binding affinity to FcγRIIIa and FcγRIIIb. Additionally, FcγRIIIa-158F exhibited higher binding activity than FcγRIIIa-158V despite having similar levels of ADCC, which suggests FcγRIIIa-158F may induce ADCC more efficiently. The deconvolution methods we present can be applied in the future to other responses mediated by Fcγ receptors such as complement activation