Immunoglobulin G Fc region N-linked glycan at Asparagine 297 (IgG Fc Asn297 glycan)

The N-linked glycan at Asparagine 297 (Asn297) is a critical structural component located within the CH2 domain of the Fc region of Immunoglobulin G (IgG) (Jefferis, 2009). This biantennary complex-type oligosaccharide is essential for maintaining the open conformation of the Fc region, which is required for binding to Fc gamma receptors (FcγRs) and the C1q complement protein (Pereira et al., 2018). Variations in the glycan's composition—specifically the presence of fucose, galactose, sialic acid, and bisecting N-acetylglucosamine—act as a molecular switch to modulate the antibody's pro- or anti-inflammatory activities (Wang & Amin, 2014). In oncology, therapeutic antibodies are often glycoengineered to lack core fucose (afucosylation) at Asn297, which significantly enhances their affinity for FcγRIIIa and boosts antibody-dependent cellular cytotoxicity (ADCC) against tumor cells (Pereira et al., 2018). Conversely, in autoimmune diseases, the enzymatic removal of this glycan by bacterial enzymes like Endoglycosidase S (EndoS) is being explored as a strategy to neutralize pathogenic autoantibodies by preventing them from activating effector cells (Sjögren et al., 2015). Consequently, the Asn297 glycan is a central target for optimizing the efficacy and safety of monoclonal antibody therapies.

Other names

Asn297 glycanFc-linked oligosaccharideIgG glycosylation siteN297 glycanFc N-glycan

Modulation of Fc gamma receptor (FcγR) affinity through glycoengineering (e.g., afucosylation) or enzymatic cleavage to alter immune effector functions (Jefferis, 2009; Pereira et al., 2018).