The molecular basis of immunosuppression by soluble CD52 is defined by interactions of N-linked and O-linked glycans with HMGB1 box B
- Author(s)
- DeBono, NJ; D'Andrea, S; Bandala-Sanchez, E; Goddard-Borger, E; Zenaidee, MA; Moh, ESX; Fadda, E; Harrison, LC; Packer, NH;
- Details
- Publication Year 2025-04,Volume 301,Issue #4,Page 108350
- Journal Title
- Journal of Biological Chemistry
- Abstract
- Human soluble CD52 is a short glycopeptide comprising 12 amino acids (GQNDTSQTSSPS) which functions as an immune regulator by sequestering the pro-inflammatory high mobility group box protein 1 (HMGB1) and suppressing immune responses. Recombinant CD52 has been shown to act as a broad anti-inflammatory agent, dampening both adaptive and innate immune responses. This short glycopeptide is heavily glycosylated, with a complex sialylated N-linked glycan at N3 and reported O-linked glycosylation possible on several serine and threonine residues. Previously we demonstrated that specific glycosylation features of CD52 are essential for its immunosuppressive function, with terminal alpha-2,3-linked sialic acids required for binding to the inhibitory SIGLEC-10 receptor leading to T-cell suppression. Using high resolution mass spectrometry, we have further characterized the N- and O-linked glycosylation of Expi293 recombinantly produced CD52 at a glycopeptide and released glycan level, accurately determining glycan heterogeneity of both N- and O-linked glycosylation, and localizing the site of O-glycosylation to T8 with high confidence and direct spectral evidence. This detailed knowledge of CD52 glycosylation informed the construction of a model system, which we analyzed by molecular dynamics simulations to understand the mechanism of recognition and define interactions between bioactive CD52, HMGB1 and the SIGLEC-10 receptor. Our results confirm the essential role of glycosylation, more specifically hyper-sialylation, in the function of CD52, and identify at the atomistic level specific interactions between CD52 glycans and the Box B domain of HMGB1 that determine recognition, and the stability of the CD52/HMGB1 complex. These insights will inform the development of synthetic CD52 as an immunotherapeutic agent.
- Publisher
- Elsevier
- Keywords
- *HMGB1 Protein/metabolism/chemistry/immunology; Humans; *CD52 Antigen/chemistry/metabolism; *Polysaccharides/chemistry/metabolism/immunology; Glycosylation; *Immune Tolerance; Cd52; Hmgb1; glycomics; glycoprotein; mass spectrometry; molecular dynamics
- Research Division(s)
- Immunology; New Medicines and Diagnostics; New Medicines and Diagnostics
- PubMed ID
- 40015632
- Publisher's Version
- https://doi.org/10.1016/j.jbc.2025.108350
- Open Access at Publisher's Site
https://doi.org/10.1016/j.jbc.2025.108350- Terms of Use/Rights Notice
- Refer to copyright notice on published article.
Creation Date: 2025-05-29 02:28:57
Last Modified: 2025-05-29 02:41:18