Contrasting glycosylation profiles between Fab and Fc of a human IgG protein studied by electrospray ionization mass spectrometry

J Immunol Methods. 2007 Sep 30;326(1-2):116-26. doi: 10.1016/j.jim.2007.07.014. Epub 2007 Aug 8.


A conserved structural feature of human IgG molecules is the presence of an oligosaccharide moiety within the Fc region at Asn297. In addition, 15-20% of normal polyclonal IgG molecules bear N-linked oligosaccharides in the variable (V) regions of the light (L) and/or heavy (H) chains. Electrospray ionization mass spectrometry (ESI-MS) has been applied to the glycan analysis of two IgG1 myeloma proteins (Wid and Cri) after mild reduction and acidification. Heterogeneous ion peaks were observed for both the H and L chains of Wid in contrast to Cri whose L chain peak was homogeneous. Site-specific deglycosylation of the H and L chains of IgG Wid was achieved under native conditions with peptide-N-glycosidase F and endoglycosidase F2, respectively. The Fc glycoforms differed between the two proteins in that Cri-Fc bears diantennary complex-type glycans that are fully core-fucosylated and partially sialylated while Wid-Fc glycans are non-fucosylated, partially galactosylated and non-sialylated. In contrast to the Fc glycans, the L chain glycans of Wid were shown to be fucosylated, fully galactosylated and sialylated, indicating that the glycosylation machinery of the Wid-producing myeloma cells is intact. Thus, combination of the two endoglycosidases can provide a simple means of glycan analysis of both Fab and Fc by ESI-MS, which may contribute to the development of therapeutic IgG with customized glycan profiles.

Publication types

  • Comparative Study

MeSH terms

  • Carbohydrate Sequence
  • Chromatography, High Pressure Liquid
  • Glycosylation
  • Humans
  • Immunoglobulin Fab Fragments / chemistry*
  • Immunoglobulin Fab Fragments / metabolism*
  • Immunoglobulin Fc Fragments / chemistry*
  • Immunoglobulin Fc Fragments / metabolism*
  • Immunoglobulin G / chemistry*
  • Immunoglobulin Heavy Chains / chemistry
  • Immunoglobulin Heavy Chains / metabolism
  • Immunoglobulin Light Chains / chemistry
  • Immunoglobulin Light Chains / metabolism
  • Molecular Sequence Data
  • Multiple Myeloma / blood
  • Multiple Myeloma / immunology
  • Spectrometry, Mass, Electrospray Ionization*


  • Immunoglobulin Fab Fragments
  • Immunoglobulin Fc Fragments
  • Immunoglobulin G
  • Immunoglobulin Heavy Chains
  • Immunoglobulin Light Chains