Abstract
Although N-linked glycans play pivotal roles in the regulation of antibody effector functions, little is known about the composition and functional impact of glycans attached to human B cell receptors (BCR). Here, we describe the site-specific glycosylation profiles of all 4 N-linked glycosylation sites of human Igµ BCRs from primary naive and memory B cells. Our data indicate that the Igµ BCR glycans do not undergo structural changes during transition from naive to memory cells, as healthy donor-derived BCRs from both B cell subtypes carry similar glycans. Conversely, serum IgM antibodies display distinct glycosylation features to Igµ BCRs, which are in part explained by the different molecular form of Igµ BCRs and IgM antibodies. Moreover, using B cell lines expressing defined BCRs, we show that, although the absence of the Igµ BCR N209 glycans reduces antigen binding, the individual glycosylation sites are nonessential for cell surface expression and BCR internalization following BCR triggering. Collectively, we show high conservation of Igµ BCR glycosylation across B cell subsets and limited contribution to BCR expression and function, suggesting BCR glycans may have evolved to support IgM antibody functions.
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Data availability
The minimum dataset, including all experimental values and images are available in the source data file. Processed LC-MS tables and statistic tables are available in Supplementary Data 1–5. available in the source data file. The raw LC-MS proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE36 partner repository with the dataset identifier PXD062559 https://www.ebi.ac.uk/pride/archive/projects/PXD062559. The original Cryo-EM Igµ BCR structure file can be found on the protein data bank with code 7XQ8. https://doi.org/10.2210/pdb7XQ8/pdb Source data are provided in this paper.
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This work is funded by the ERC GlycanSwitch grant 101071386.
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MDHK conceived the project, designed experiments, performed a majority of the experiments and analyzed the data. LH critically assessed project progress, contributed to intellectual discussions, provided literature resources and ideas, analyzed and visualized the LC-MS data. S.K. and R.B. contributed with the generation of B cell lines and their subsequent sorting, and performed antigen-titration experiments. RvdW performed B-cell isolation and B-cell sorting experiments. RTNT, PAvV designed and performed all LC-MS experiments and analyzed the data. O.S. and E.F. performed and analyzed the 3D reconstruction of the N209-glycosylated Igµ BCR. D.F. and M.W. contributed to the analysis, interpretation and visualization of LC-MS data. REMT conceived the project, designed experiments and supervised the project. All authors contributed to the revision of the manuscript.
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Holborough-Kerkvliet, M.D., Hafkenscheid, L., Kroos, S. et al. Site-specific profiling of structure and function of Igµ B cell receptor glycans. Nat Commun (2026). https://doi.org/10.1038/s41467-026-70121-y
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DOI: https://doi.org/10.1038/s41467-026-70121-y
