{"entity": "publication", "iuid": "384157cca3f94b41861070e13b895e6c", "timestamp": "2026-09-25T23:05:15.641Z", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/384157cca3f94b41861070e13b895e6c.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/384157cca3f94b41861070e13b895e6c"}}, "title": "Multimodal Mass Spectrometry Identifies a Conserved Protective Epitope in S. pyogenes Streptolysin O.", "authors": [{"family": "Tang", "given": "Di", "initials": "D", "orcid": "0000-0001-6323-9375", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/71ab26121ccb4cbcb99161cea8aca0cd.json"}}, {"family": "Gueto-Tettay", "given": "Carlos", "initials": "C"}, {"family": "Hjortswang", "given": "Elisabeth", "initials": "E"}, {"family": "Str\u00f6baek", "given": "Joel", "initials": "J"}, {"family": "Ekstr\u00f6m", "given": "Simon", "initials": "S"}, {"family": "Happonen", "given": "Lotta", "initials": "L", "orcid": "0000-0002-5922-4549", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/687cf1ac5c8e4c52add689341b2d61e8.json"}}, {"family": "Malmstr\u00f6m", "given": "Lars", "initials": "L"}, {"family": "Malmstr\u00f6m", "given": "Johan", "initials": "J"}], "type": "journal article", "published": "2024-06-04", "journal": {"title": "Anal. Chem.", "issn": "1520-6882", "volume": "96", "issue": "22", "pages": "9060-9068", "issn-l": "0003-2700"}, "abstract": "An important element of antibody-guided vaccine design is the use of neutralizing or opsonic monoclonal antibodies to define protective epitopes in their native three-dimensional conformation. Here, we demonstrate a multimodal mass spectrometry-based strategy for in-depth characterization of antigen-antibody complexes to enable the identification of protective epitopes using the cytolytic exotoxin Streptolysin O (SLO) from Streptococcus pyogenes as a showcase. We first discovered a monoclonal antibody with an undisclosed sequence capable of neutralizing SLO-mediated cytolysis. The amino acid sequence of both the antibody light and the heavy chain was determined using mass-spectrometry-based de novo sequencing, followed by chemical cross-linking mass spectrometry to generate distance constraints between the antibody fragment antigen-binding region and SLO. Subsequent integrative computational modeling revealed a discontinuous epitope located in domain 3 of SLO that was experimentally validated by hydrogen-deuterium exchange mass spectrometry and reverse engineering of the targeted epitope. The results show that the antibody inhibits SLO-mediated cytolysis by binding to a discontinuous epitope in domain 3, likely preventing oligomerization and subsequent secondary structure transitions critical for pore-formation. The epitope is highly conserved across >98% of the characterized S. pyogenes isolates, making it an attractive target for antibody-based therapy and vaccine design against severe streptococcal infections.", "doi": "10.1021/acs.analchem.4c00596", "pmid": "38701337", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC11154737"}], "notes": [], "created": "2026-09-23T12:12:14.993Z", "modified": "2026-09-23T12:12:15.054Z"}