Title
Site-specific N-glycan Analysis of Antibody-binding Fc γ Receptors from Primary Human Monocytes
Campus Units
Biochemistry, Biophysics and Molecular Biology, Roy J. Carver Department of
Document Type
Article
Publication Version
Published Version
Publication Date
2-1-2020
Journal or Book Title
Molecular & Cellular Proteomics
Volume
19
Issue
2
First Page
362
Last Page
374
DOI
10.1074/mcp.RA119.001733
Abstract
FcγRIIIa (CD16a) and FcγRIIa (CD32a) on monocytes are essential for proper effector functions including antibody dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP). Indeed, therapeutic monoclonal antibodies (mAbs) that bind FcγRs with greater affinity exhibit greater efficacy. Furthermore, post-translational modification impacts antibody binding affinity, most notably the composition of the asparagine(N)-linked glycan at N162 of CD16a. CD16a is widely recognized as the key receptor for the monocyte response, however the post-translational modifications of CD16a from endogenous monocytes are not described. Here we isolated monocytes from individual donors and characterized the composition of CD16a and CD32a N-glycans from all modified sites. The composition of CD16a N-glycans varied by glycosylation site and donor. CD16a displayed primarily complex-type biantennary N-glycans at N162, however some individuals expressed CD16a V158 with ∼20% hybrid and oligomannose types which increased affinity for IgG1 Fc according to surface plasmon resonance binding analyses. The CD16a N45-glycans contain markedly less processing than other sites with >75% hybrid and oligomannose forms. N38 and N74 of CD16a both contain highly processed complex-type N-glycans with N-acetyllactosamine repeats and complex-type biantennary N-glycans dominate at N169. The composition of CD16a N-glycans isolated from monocytes included a higher proportion of oligomannose-type N-glycans at N45 and less sialylation plus greater branch fucosylation than we observed in a recent analysis of NK cell CD16a. The additional analysis of CD32a from monocytes revealed different features than observed for CD16a including the presence of a predominantly biantennary complex-type N-glycans with two sialic acids at both sites (N64 and N145).
Copyright Owner
Roberts et al.
Copyright Date
2020
Language
en
File Format
application/pdf
Recommended Citation
Roberts, Jacob T.; Patel, Kashyap R.; and Barb, Adam W., "Site-specific N-glycan Analysis of Antibody-binding Fc γ Receptors from Primary Human Monocytes" (2020). Biochemistry, Biophysics and Molecular Biology Publications. 281.
https://lib.dr.iastate.edu/bbmb_ag_pubs/281
Included in
Biochemistry Commons, Biophysics Commons, Molecular Biology Commons, Structural Biology Commons
Comments
This research was originally published in Molecular and Cellular Proteomics. Roberts, Jacob T., Kashyap R. Patel, and Adam W. Barb. "Site-specific N-glycan analysis of antibody-binding Fc γ receptors from primary human monocytes." Molecular & Cellular Proteomics 2020; 19:362-374. © Roberts et al. doi: 10.1074/mcp.RA119.001733.