title: Yersinia enterocolitica provides the link between thyroid-stimulating antibodies and their germline counterparts in Graves' disease.
abstract: Graves' disease results from thyroid-stimulating Abs (TSAbs) activating the thyrotropin receptor (TSHR). How TSAbs arise from early precursor B cells has not been established. Genetic and environmental factors may contribute to pathogenesis, including the bacterium Yersinia enterocolitica. We developed two pathogenic monoclonal TSAbs from a single experimental mouse undergoing Graves' disease, which shared the same H and L chain germline gene rearrangements and then diversified by numerous somatic hypermutations. To address the Ag specificity of the shared germline precursor of the monoclonal TSAbs, we prepared rFab germline, which showed negligible binding to TSHR, indicating importance of somatic hypermutation in acquiring TSAb activity. Using rFab chimeras, we demonstrate the dominant role of the H chain V region in TSHR recognition. The role of microbial Ags was tested with Y. enterocolitica proteins. The monoclonal TSAbs recognize 37-kDa envelope proteins, also recognized by rFab germline. MALDI-TOF identified the proteins as outer membrane porin (Omp) A and OmpC. Using recombinant OmpA, OmpC, and related OmpF, we demonstrate cross-reactivity of monoclonal TSAbs with the heterogeneous porins. Importantly, rFab germline binds recombinant OmpA, OmpC, and OmpF confirming reactivity with Y. enterocolitica. A human monoclonal TSAb, M22 with similar properties to murine TSAbs, also binds recombinant porins, showing cross-reactivity of a spontaneously arising pathogenic Ab with Y. enterocolitica. The data provide a mechanistic framework for molecular mimicry in Graves' disease, where early precursor B cells are expanded by Y. enterocolitica porins to undergo somatic hypermutation to acquire a cross-reactive pathogenic response to TSHR.
authors: Division of Diabetes and Nutritional Sciences, King's College London School of Medicine, London SE5 9NU, United Kingdom.
authors: Chantal E
authors: CE
authors: Hargreaves
authors: Marco
authors: M
authors: Grasso
authors: Christiane S
authors: CS
authors: Hampe
authors: Anna
authors: A
authors: Stenkova
authors: Steve
authors: S
authors: Atkinson
authors: George W P
authors: GW
authors: Joshua
authors: Brendan W
authors: BW
authors: Wren
authors: Ashley M
authors: AM
authors: Buckle
authors: Deborah
authors: D
authors: Dunn-Walters
authors: J Paul
authors: JP
authors: Banga
mesh_terms: D000911:Antibodies, Monoclonal / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D015870:Gene Expression; D018095:Germ-Line Mutation; D006111:Graves Disease / Q000209:etiology* / Q000235:genetics / Q000276:immunology; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D007074:Immunoglobulin G / Q000276:immunology / Q000378:metabolism; D007135:Immunoglobulin Variable Region / Q000235:genetics; D018828:Immunoglobulins, Thyroid-Stimulating / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D011485:Protein Binding / Q000276:immunology; D021122:Protein Subunits / Q000276:immunology / Q000378:metabolism; D011989:Receptors, Thyrotropin / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins; D015008:Yersinia enterocolitica / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D007135:Immunoglobulin Variable Region; D018828:Immunoglobulins, Thyroid-Stimulating; D021122:Protein Subunits; D011989:Receptors, Thyrotropin; D011994:Recombinant Proteins