Figure 1.

IgG Fc N-glycan structure and representative chromatogram of IgG Fc N-glycans. (A) The glycan structure is composed of a biantennary core heptasaccharide comprised of N-acetylglucosamines (GlcNAc or GNAc, blue) and mannoses (Man, green). The core structure can be further modified by addition of fucose (Fuc), bisecting GlcNAc (GNAc, blue), galactose (G, yellow), or sialic acid (Neu5Ac, purple). (B) The different Fc N-glycan modifications G0, G0GNAc, G1, G1GNAc, G2, G2GNAc, G1S1, G2S1 and G2S2 (not marked in this sample analysis) were detected using hydrophilic interaction liquid chromatography (representative chromatogram), where glycans with higher hydrophobicity (e.g., more sugar units) were retained longer by the column. Glycan composition of collected fractions containing individual peaks was previously identified by MALDI-TOF analysis (38).