Fc-Linked IgG N-Glycosylation in FcγR Knock-Out Mice

Immunoglobulin G (IgG) is the most abundant immunoglobulin isotype in the blood and is involved in the pathogenesis and progression of various diseases. Glycosylation of the IgG fragment crystallizable (Fc) region is shown to vary in different physiological and pathological states. Fc N-glycan composition can alter the effector functions of IgG by modulating its affinity for ligands, such as Fc gamma receptors (Fc gamma Rs). However, it is not known whether IgG glycosylation is affected by the available repertoire of Fc gamma Rs, and if the Fc-linked N-glycome can compensate for modulation of the IgG-Fc gamma R interaction. To explore this, we examined the subclass-specific Fc IgG glycoprofiles of healthy male and female Fc gamma R knock-out mice on C57BL/6 and BALB/c backgrounds. We observed slight changes in IgG Fc N-glycan profiles in different knock-outs; however, it seems that the strain background and sex have a stronger effect on N-glycosylation of IgG Fc regions than the Fc gamma R repertoire.