Immunoglobulin G glycoform (IgG glycoform)

Immunoglobulin G (IgG) glycoforms refer to the diverse set of glycosylation patterns found at the conserved N-glycosylation site (Asn297) within the Fc region of antibodies (Wang et al., 2018, Nature Reviews Drug Discovery). These glycans are critical determinants of the antibody's structural integrity and its ability to engage with effector molecules, such as Fc gamma receptors (FcγRs) and the C1q component of the complement system (Shields et al., 2002, JBC). By altering the composition of these sugar chains—specifically through the removal of fucose (afucosylation) or the addition of sialic acid—the therapeutic efficacy of monoclonal antibodies can be significantly enhanced. For instance, afucosylated antibodies exhibit a dramatically increased affinity for FcγRIIIa, leading to more potent antibody-dependent cellular cytotoxicity (ADCC) against tumor cells, as seen in drugs like Obinutuzumab (Gazyva FDA Label). Conversely, highly sialylated IgG glycoforms are associated with the anti-inflammatory properties of intravenous immunoglobulin (IVIG) therapy, making them relevant for treating autoimmune conditions (Kaneko et al., 2006, Science). Consequently, glycoengineering has become a cornerstone of modern biopharmaceutical development to optimize the safety, potency, and pharmacokinetics of therapeutic antibodies.

Other names

Antibody glycoformFc-glycanIgG glycosylation variantGlycoengineered antibodyN-linked glycan of IgG

Modulation of the antibody Fc region's affinity for Fc gamma receptors (FcγRs) or complement proteins through specific glycan modifications, such as afucosylation to enhance ADCC or sialylation to promote anti-inflammatory activity.