Influence of Glycan Modification on IgG1 Biochemical and Biophysical Properties

Pawlowski JW, et al., 151:133-144, J Pharm Biomed Anal., 2018

Described herein is the effect of glycan chains on the IgG1 interaction with two key receptor families, FcRn and γ-type Fc receptors. Furthermore, the impact of glycan composition on the conformation and stability of the antibody molecule was investigated using three different glycan-modified variants of mAb (fully deglycosylated, hypergalactosylated and hypersialylated) alongside the unmodified mAb molecule. The kinetics of IgG1 binding to FcRn fusion protein was studied by Bio-Layer Interferometry (BLI) using a Pall ForteBio Octet QKe instrument equipped with Streptavidin (SA) Biosensor probes. Biotinylated FcRn was immobilized onto SA sensor tips. Subsequently, biotinylated FcRn loaded sensor tips were dipped in wells containing various concentrations of IgG1 protein samples for an association step, followed by a dissociation step in the buffer. Experimental data obtained were globally fitted to a 1:1 binding model. Association rate constants (kon), dissociation rate constants (koff), and the KD values were determined for each of the IgG1/FcRn interactions studied. Overall results of this study highlight the effect of Fc glycosylation on the biochemical and biophysical properties of an IgG1 molecule.

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