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 language | English |
---|---|
Pages (from-to) | 2048-2058 |
Number of pages | 11 |
Journal | ACS Central Science |
Volume | 10 |
Issue number | 11 |
Early online date | 9 Oct 2024 |
DOIs | |
Publication status | Published - 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.).
Funders | Funder number |
---|---|
Netherlands Organization for Scientific Research (NWO) | 184.034.019, VI.Veni.192.058 |
China Scholarship Council (CSC) | 202106235027 |