Figure 1.

Structure and glycan composition of IgG. A. Schematic representation of immunoglobulin G with heavy chains and light chains in a general Y-shaped structure. Fab glycans are usually more galactosylated and sialylated but less fucosylated than Fc N-glycans. Fc glycans are rarely fully processed and can differ in composition between each CH2 domain of the same IgG molecule. B. The classification of Fc Asn-297 glycans by different glycoforms. N-glycans can also be galactosylated, sialylated or fucosylated, and these modifications alter the anti-inflammatory activity of IgG. The anti-inflammatory activity of immunoglobulin with different Fc N-glycan modifications increases from G0 to G2S2F. Ig, immunoglobulin; CH, constant heavy; CL, constant light; VH, variable heavy; VL, variable light; G, galactose; S, sialic acid; F, fucose.