TY - JOUR
T1 - A photoaffinity glycan-labeling approach to investigate immunoglobulin glycan-binding partners
AU - Holborough-Kerkvliet, Miles D.
AU - Mucignato, Greta
AU - Moons, Sam J.
AU - Psomiadou, Venetia
AU - Konada, Rohit S.R.
AU - Pedowitz, Nichole J.
AU - Pratt, Matthew R.
AU - Kissel, Theresa
AU - Koeleman, Carolien A.M.
AU - Tjokrodirijo, Rayman T.N.
AU - Van Veelen, Petrus A.
AU - Huizinga, Thomas
AU - Van Schie, Karin A.J.
AU - Wuhrer, Manfred
AU - Kohler, Jennifer J.
AU - Bonger, Kimberly M.
AU - Boltje, Thomas J.
AU - Toes, Reinaldus E.M.
N1 - Publisher Copyright:
© 2023 The Author(s). Published by Oxford University Press.
PY - 2023/9/1
Y1 - 2023/9/1
N2 - Glycans play a pivotal role in biology. However, because of the low-affinity of glycan-protein interactions, many interaction pairs remain unknown. Two important glycoproteins involved in B-cell biology are the B-cell receptor and its secreted counterpart, antibodies. It has been indicated that glycans expressed by these B-cell-specific molecules can modulate immune activation via glycan-binding proteins. In several autoimmune diseases, an increased prevalence of variable domain glycosylation of IgG autoantibodies has been observed. Especially, the hallmarking autoantibodies in rheumatoid arthritis, anti-citrullinated protein antibodies, carry a substantial amount of variable domain glycans. The variable domain glycans expressed by these autoantibodies are N-linked, complex-type, and α2-6 sialylated, and B-cell receptors carrying variable domain glycans have been hypothesized to promote selection of autoreactive B cells via interactions with glycan-binding proteins. Here, we use the anti-citrullinated protein antibody response as a prototype to study potential in solution and in situ B-cell receptor-variable domain glycan interactors. We employed SiaDAz, a UV-activatable sialic acid analog carrying a diazirine moiety that can form covalent bonds with proximal glycan-binding proteins. We show, using oligosaccharide engineering, that SiaDAz can be readily incorporated into variable domain glycans of both antibodies and B-cell receptors. Our data show that antibody variable domain glycans are able to interact with inhibitory receptor, CD22. Interestingly, although we did not detect this interaction on the cell surface, we captured CD79 β glycan-B-cell receptor interactions. These results show the utility of combining photoaffinity labeling and oligosaccharide engineering for identifying antibody and B-cell receptor interactions and indicate that variable domain glycans appear not to be lectin cis ligands in our tested conditions.
AB - Glycans play a pivotal role in biology. However, because of the low-affinity of glycan-protein interactions, many interaction pairs remain unknown. Two important glycoproteins involved in B-cell biology are the B-cell receptor and its secreted counterpart, antibodies. It has been indicated that glycans expressed by these B-cell-specific molecules can modulate immune activation via glycan-binding proteins. In several autoimmune diseases, an increased prevalence of variable domain glycosylation of IgG autoantibodies has been observed. Especially, the hallmarking autoantibodies in rheumatoid arthritis, anti-citrullinated protein antibodies, carry a substantial amount of variable domain glycans. The variable domain glycans expressed by these autoantibodies are N-linked, complex-type, and α2-6 sialylated, and B-cell receptors carrying variable domain glycans have been hypothesized to promote selection of autoreactive B cells via interactions with glycan-binding proteins. Here, we use the anti-citrullinated protein antibody response as a prototype to study potential in solution and in situ B-cell receptor-variable domain glycan interactors. We employed SiaDAz, a UV-activatable sialic acid analog carrying a diazirine moiety that can form covalent bonds with proximal glycan-binding proteins. We show, using oligosaccharide engineering, that SiaDAz can be readily incorporated into variable domain glycans of both antibodies and B-cell receptors. Our data show that antibody variable domain glycans are able to interact with inhibitory receptor, CD22. Interestingly, although we did not detect this interaction on the cell surface, we captured CD79 β glycan-B-cell receptor interactions. These results show the utility of combining photoaffinity labeling and oligosaccharide engineering for identifying antibody and B-cell receptor interactions and indicate that variable domain glycans appear not to be lectin cis ligands in our tested conditions.
KW - B-cell receptor
KW - CD22
KW - antibodies
KW - photoaffinity labeling
KW - variable domain glycans
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U2 - 10.1093/glycob/cwad055
DO - 10.1093/glycob/cwad055
M3 - Article
C2 - 37498177
AN - SCOPUS:85176496808
SN - 0959-6658
VL - 33
SP - 732
EP - 744
JO - Glycobiology
JF - Glycobiology
IS - 9
ER -