FIGURE 1.

Glycosylation profiling of serum IgG and recombinantly expressed IgG fragments. Shown is SDS-PAGE analysis of serum IgG and purified IgG fragments (A). Shown is HPLC analysis of fluorescently labeled glycans released from serum IgG (B) and recombinantly expressed Fc (C), CH2-H (D), and CH2 (E) using PNGase F. Peaks were assigned using negative ion electrospray ionization-MS/MS and are labeled using Oxford glycan nomenclature (46) with the color scheme of the Consortium for Functional Glycomics as previously implemented (20, 47). The star denotes glycan with the composition Neu5Ac₂Hex₅GlcNAc₄ (probably Neu5Ac₂Gal₂GlcNAc₂Man₃GlcNAc₂), which was present in too low a quantity for fragmentation analysis. Fluorescence is reported as relative fluorescence units (RF).