Human IgG Subclasses Differ in the Structural Elements of Their N-Glycosylation

Weiwei Wang*, Joshua C.L. Maliepaard, Timon Damelang, Gestur Vidarsson, Albert J.R. Heck, Karli R. Reiding*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Although immunoglobulin G (IgG) harbors just one N-glycosylation site per heavy chain, this glycosylation plays a key role in modulating its function. In human serum, IgG is classified into four subclasses (IgG1, IgG2, IgG3, IgG4), each characterized by unique features in their sequences, disulfide bridges and glycosylation signatures. While protein glycosylation is typically studied at the compositional level, this severely underestimates the complexity of the molecules involved. Glycan functionality heavily relies on the precise linkages and branching between monosaccharides, yet these features are challenging to study. Here, by development of a nanohydrophilic interaction chromatography (HILIC)-LC-MS/MS method, we reveal distinct structural glycosylation signatures for each of the four IgG subclasses, namely that IgG1 and IgG3 display predominant galactosylation of the 6-branched antenna, IgG2 instead of the 3-branched antenna, while IgG4 displays a balance. These and other subclass-specific glycostructural elements proved observable in both recombinant and endogenous IgGs as present in human plasma, in which interindividual differences and temporal stability could be demonstrated. Structural glycoproteomics is expected to fundamentally alter the way in which we study IgG, opening up a new layer of functional investigation and biomarker development, while also revealing new key structural differences between recombinant IgG subclasses in therapeutic applications.

Original languageEnglish
Pages (from-to)2048-2058
Number of pages11
JournalACS Central Science
Volume10
Issue number11
Early online date9 Oct 2024
DOIs
Publication statusPublished - 27 Nov 2024

Bibliographical note

Publisher Copyright:
© 2024 The Authors. Published by American Chemical Society.

Funding

This work was supported by The Netherlands Organization for Scientific Research (NWO) through X-omics Road Map program project 184.034.019 (awarded to A.J.R.H.), Veni project VI.Veni.192.058 (awarded to K.R.R.) and China Scholarship Council (CSC) project no. 202106235027 (awarded to W.W.).

FundersFunder number
Netherlands Organization for Scientific Research (NWO)184.034.019, VI.Veni.192.058
China Scholarship Council (CSC)202106235027

    Fingerprint

    Dive into the research topics of 'Human IgG Subclasses Differ in the Structural Elements of Their N-Glycosylation'. Together they form a unique fingerprint.

    Cite this