Advanced

Human IgG/FcgammaR Interactions Are Modulated by Streptococcal IgG Glycan Hydrolysis.

Allhorn, Maria LU ; Olin, Anders I; Nimmerjahn, Falk and Collin, Mattias LU (2008) In PLoS ONE 3(1).
Abstract
BACKGROUND: The human pathogen Streptococcus pyogenes produces an endoglycosidase, EndoS that hydrolyzes the chitobiose core of the asparagine-linked glycan on the heavy chain of human IgG. IgG-binding to Fc gamma receptors (FcgammaR) on leukocytes triggers effector functions including phagocytosis, oxidative burst and the release of inflammatory mediators. The interactions between FcgammaR and the Fc domain of IgG depend on the IgG glycosylation state. METHODOLOGY/PRINCIPAL FINDINGS: Here we show for the first time that EndoS hydrolyzes the heavy chain glycan of all four human IgG subclasses (IgG1-4), in purified form and in a plasma environment. An inactive form of EndoS, obtained by site-directed mutagenesis, binds IgG with high... (More)
BACKGROUND: The human pathogen Streptococcus pyogenes produces an endoglycosidase, EndoS that hydrolyzes the chitobiose core of the asparagine-linked glycan on the heavy chain of human IgG. IgG-binding to Fc gamma receptors (FcgammaR) on leukocytes triggers effector functions including phagocytosis, oxidative burst and the release of inflammatory mediators. The interactions between FcgammaR and the Fc domain of IgG depend on the IgG glycosylation state. METHODOLOGY/PRINCIPAL FINDINGS: Here we show for the first time that EndoS hydrolyzes the heavy chain glycan of all four human IgG subclasses (IgG1-4), in purified form and in a plasma environment. An inactive form of EndoS, obtained by site-directed mutagenesis, binds IgG with high affinity, in contrast to wild type EndoS that only transiently interacts with IgG, as shown by Slot-blotting and surface plasmon resonance technology. Furthermore, EndoS hydrolysis of the IgG glycan influences the binding of IgG to immobilized soluble FcgammaR and to an erythroleukemic cell line, K562, expressing FcgammaRIIa. Incubation of whole blood with EndoS results in a dramatic decrease of IgG binding to activated monocytes as analyzed by flow cytometry. Moreover, the IgG bound to K562 cells dissociates when cells are treated with EndoS. Likewise, IgG bound to immobilized FcgammaRIIa and subsequently treated with EndoS, dissociates from the receptor as analyzed by surface plasmon resonance and Western blot. CONCLUSIONS/SIGNIFICANCE: We provide novel information about bacterial enzymatic modulation of the IgG/FcgammaR interaction that emphasizes the importance of glycosylation for antibody effector functions. Moreover, EndoS could be used as a biochemical tool for specific IgG N-glycan hydrolysis and IgG purification/detection, or as a potential immunosuppressing agent for treatment of antibody-mediated pathological processes. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
PLoS ONE
volume
3
issue
1
publisher
Public Library of Science
external identifiers
  • pmid:18183294
  • wos:000260469400010
  • scopus:39049094267
ISSN
1932-6203
DOI
10.1371/journal.pone.0001413
language
English
LU publication?
yes
id
03e2c97f-ff79-4160-9169-faeb8a4718d9 (old id 1021523)
alternative location
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2173940/
date added to LUP
2008-02-05 15:19:18
date last changed
2017-08-06 04:52:52
@article{03e2c97f-ff79-4160-9169-faeb8a4718d9,
  abstract     = {BACKGROUND: The human pathogen Streptococcus pyogenes produces an endoglycosidase, EndoS that hydrolyzes the chitobiose core of the asparagine-linked glycan on the heavy chain of human IgG. IgG-binding to Fc gamma receptors (FcgammaR) on leukocytes triggers effector functions including phagocytosis, oxidative burst and the release of inflammatory mediators. The interactions between FcgammaR and the Fc domain of IgG depend on the IgG glycosylation state. METHODOLOGY/PRINCIPAL FINDINGS: Here we show for the first time that EndoS hydrolyzes the heavy chain glycan of all four human IgG subclasses (IgG1-4), in purified form and in a plasma environment. An inactive form of EndoS, obtained by site-directed mutagenesis, binds IgG with high affinity, in contrast to wild type EndoS that only transiently interacts with IgG, as shown by Slot-blotting and surface plasmon resonance technology. Furthermore, EndoS hydrolysis of the IgG glycan influences the binding of IgG to immobilized soluble FcgammaR and to an erythroleukemic cell line, K562, expressing FcgammaRIIa. Incubation of whole blood with EndoS results in a dramatic decrease of IgG binding to activated monocytes as analyzed by flow cytometry. Moreover, the IgG bound to K562 cells dissociates when cells are treated with EndoS. Likewise, IgG bound to immobilized FcgammaRIIa and subsequently treated with EndoS, dissociates from the receptor as analyzed by surface plasmon resonance and Western blot. CONCLUSIONS/SIGNIFICANCE: We provide novel information about bacterial enzymatic modulation of the IgG/FcgammaR interaction that emphasizes the importance of glycosylation for antibody effector functions. Moreover, EndoS could be used as a biochemical tool for specific IgG N-glycan hydrolysis and IgG purification/detection, or as a potential immunosuppressing agent for treatment of antibody-mediated pathological processes.},
  articleno    = {e1413},
  author       = {Allhorn, Maria and Olin, Anders I and Nimmerjahn, Falk and Collin, Mattias},
  issn         = {1932-6203},
  language     = {eng},
  number       = {1},
  publisher    = {Public Library of Science},
  series       = {PLoS ONE},
  title        = {Human IgG/FcgammaR Interactions Are Modulated by Streptococcal IgG Glycan Hydrolysis.},
  url          = {http://dx.doi.org/10.1371/journal.pone.0001413},
  volume       = {3},
  year         = {2008},
}