The role of IgG in immune responses

Jeanette H.W. Leusen*, Falk Nimmerjahn

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapterAcademicpeer-review

2 Citations (Scopus)

Abstract

The glycoprotein immunoglobulin G (IgG) is a major effector molecule of the humoral immune response in man and accounts for about 75% of the total immunoglobulins in plasma of healthy individuals. Antibodies of the IgG class express their predominant activity during a secondary antibody response. In comparison to antibodies of the IgM class, IgG antibodies have a relatively high affinity and persist in the circulation for a long time. Whereas all other Ig isotypes contain multiple glycosylation sites in the antibody constant and variable domains, IgG molecules have only one sugar moiety attached to each of the CH2 domains in the IgG constant fragment. This sugar moiety consists of a heptameric core structure of N-acetylglucosamine and mannose residues with variable additions of terminal (galactose and sialic acid) and branching (fucose and N-acetylglucosamine) residues. In the serum more than 30 different IgG glycoforms can be identified, and the pattern of IgG glycosylation can change during inflammatory responses. Removal of this sugar moiety abrogates IgG function, and certain IgG glycoforms have been demonstrated to have enhanced effector functions, suggesting that regulation of IgG glycosylation may be a means of modulating IgG activity.

Original languageEnglish
Title of host publicationMolecular and Cellular Mechanisms of Antibody Activity
PublisherSpringer New York
Pages85-112
Number of pages28
Volume9781461471073
ISBN (Electronic)9781461471073
ISBN (Print)1461471060, 9781461471066
DOIs
Publication statusPublished - 1 Jul 2013

Keywords

  • Autoimmune disease
  • Humoral immunity
  • IgG
  • IgG subclasses
  • Immunoglobulins
  • Opsonisation
  • Phagocytosis

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