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Wallenius M, Lind A, Akel O, Karlsson E, Svensson M, Arvidsson E, Ramelius A, Törn C, Palm L, Lernmark Å, Elding Larsson H. Autoantibodies in Pandemrix ®-induced narcolepsy: Nine candidate autoantigens fail the conformational autoantibody test. Autoimmunity 2019; 52:185-191. [PMID: 31328572 DOI: 10.1080/08916934.2019.1643843] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Study objectives: Narcolepsy type 1 (NT1) is a chronic sleep disorder characterized by loss of hypocretin-producing neurons. Increased NT1 incidence was observed in Sweden following mass-vaccination with Pandemrix®. Genetic association to HLA DQB1*06:02 implies an autoimmune origin, but target autoantigen remains unknown. Candidate autoantigens for NT1 have previously been identified in solid-phase immunoassays, while autoantibodies against conformation-dependent epitopes are better detected in radiobinding assays. The aims are to determine autoantibody levels against nine candidate autoantigens representing (1) proteins of the hypocretin transmitter system; Preprohypocretin (ppHypocretin), Hypocretin peptides 1 and 2 (HCRT1 and HCRT2) and Hypocretin receptor 2 (HCRTR2); (2) proteins previously associated with NT1; Tribbles homologue 2 (TRIB2), Pro-opiomelanocortin/alpha-melanocyte-stimulating-hormone (POMC/α-MSH) and Prostaglandin D2 Receptor DP1 (DP1); (3) proteins suggested as autoantigens for multiple sclerosis (another HLA DQB1*06:02-associated neurological disease); ATP-dependent Inwardly Rectifying Potassium Channel Kir4.1 (KIR4.1) and Calcium-activated chloride channel Anoctamin 2 (ANO2). Methods: Serum from post-Pandemrix® NT1 patients (n = 31) and their healthy first-degree relatives (n = 66) were tested for autoantibody levels in radiobinding assays separating autoantibody bound from free labelled antigen with Protein A-Sepharose. 125I-labelled HCRT1 and HCRT2 were commercially available while 35S-methionine-labelled ppHypocretin, HCRTR2, TRIB2, α-MSH/POMC, DP1, KIR4.1 or ANO2 was prepared by in vitro transcription translation of respective cDNA. In-house standards were used to express data in arbitrary Units/ml (U/ml). Results: All radiolabelled autoantigens were detected in a concentration-dependent manner by respective standard sera. Levels of autoantibodies in the NT1 patients did not differ from healthy first-degree relatives in any of the nine candidate autoantigens. Conclusions: None of the nine labelled proteins proposed to be autoantigens were detected in the radiobinding assays for conformation-dependent autoantibodies. The results emphasise the need of further studies to identify autoantigen(s) and clarify the mechanisms in Pandemrix®-induced NT1.
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Affiliation(s)
- Madeleine Wallenius
- Department of Clinical Sciences Malmö, Lund University/CRC, Skåne University Hospital SUS , Malmö , Sweden
| | - Alexander Lind
- Department of Clinical Sciences Malmö, Lund University/CRC, Skåne University Hospital SUS , Malmö , Sweden
| | - Omar Akel
- Department of Clinical Sciences Malmö, Lund University/CRC, Skåne University Hospital SUS , Malmö , Sweden
| | - Emma Karlsson
- Department of Clinical Sciences Malmö, Lund University/CRC, Skåne University Hospital SUS , Malmö , Sweden
| | - Markus Svensson
- Department of Clinical Sciences Malmö, Lund University/CRC, Skåne University Hospital SUS , Malmö , Sweden
| | - Elin Arvidsson
- Department of Clinical Sciences Malmö, Lund University/CRC, Skåne University Hospital SUS , Malmö , Sweden
| | - Anita Ramelius
- Department of Clinical Sciences Malmö, Lund University/CRC, Skåne University Hospital SUS , Malmö , Sweden
| | - Carina Törn
- Department of Clinical Sciences Malmö, Lund University/CRC, Skåne University Hospital SUS , Malmö , Sweden
| | - Lars Palm
- Section for Paediatric Neurology, Department of Paediatrics, Skåne University Hospital SUS , Malmö , Sweden
| | - Åke Lernmark
- Department of Clinical Sciences Malmö, Lund University/CRC, Skåne University Hospital SUS , Malmö , Sweden
| | - Helena Elding Larsson
- Department of Clinical Sciences Malmö, Lund University/CRC, Skåne University Hospital SUS , Malmö , Sweden
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2
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Le SN, Porebski BT, McCoey J, Fodor J, Riley B, Godlewska M, Góra M, Czarnocka B, Banga JP, Hoke DE, Kass I, Buckle AM. Modelling of Thyroid Peroxidase Reveals Insights into Its Enzyme Function and Autoantigenicity. PLoS One 2015; 10:e0142615. [PMID: 26623656 PMCID: PMC4666655 DOI: 10.1371/journal.pone.0142615] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 10/23/2015] [Indexed: 11/18/2022] Open
Abstract
Thyroid peroxidase (TPO) catalyses the biosynthesis of thyroid hormones and is a major autoantigen in Hashimoto's disease--the most common organ-specific autoimmune disease. Epitope mapping studies have shown that the autoimmune response to TPO is directed mainly at two surface regions on the molecule: immunodominant regions A and B (IDR-A, and IDR-B). TPO has been a major target for structural studies for over 20 years; however, to date, the structure of TPO remains to be determined. We have used a molecular modelling approach to investigate plausible modes of TPO structure and dimer organisation. Sequence features of the C-terminus are consistent with a coiled-coil dimerization motif that most likely anchors the TPO dimer in the apical membrane of thyroid follicular cells. Two contrasting models of TPO were produced, differing in the orientation and exposure of their active sites relative to the membrane. Both models are equally plausible based upon the known enzymatic function of TPO. The "trans" model places IDR-B on the membrane-facing side of the myeloperoxidase (MPO)-like domain, potentially hindering access of autoantibodies, necessitating considerable conformational change, and perhaps even dissociation of the dimer into monomers. IDR-A spans MPO- and CCP-like domains and is relatively fragmented compared to IDR-B, therefore most likely requiring domain rearrangements in order to coalesce into one compact epitope. Less epitope fragmentation and higher solvent accessibility of the "cis" model favours it slightly over the "trans" model. Here, IDR-B clusters towards the surface of the MPO-like domain facing the thyroid follicular lumen preventing steric hindrance of autoantibodies. However, conformational rearrangements may still be necessary to allow full engagement with autoantibodies, with IDR-B on both models being close to the dimer interface. Taken together, the modelling highlights the need to consider the oligomeric state of TPO, its conformational properties, and its proximity to the membrane, when interpreting epitope-mapping data.
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Affiliation(s)
- Sarah N. Le
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Benjamin T. Porebski
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Julia McCoey
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - James Fodor
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Blake Riley
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Marlena Godlewska
- The Centre of Postgraduate Medical Education, Department of Biochemistry and Molecular Biology, Warsaw, Poland
| | - Monika Góra
- Institute of Biochemistry and Biophysics PAS, Department of Genetics, Warsaw, Poland
| | - Barbara Czarnocka
- The Centre of Postgraduate Medical Education, Department of Biochemistry and Molecular Biology, Warsaw, Poland
| | - J Paul Banga
- King's College London School of Medicine, Division of Diabetes and Nutrition Sciences, London, United Kingdom
| | - David E. Hoke
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Itamar Kass
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
- * E-mail: (AMB); (IK)
| | - Ashley M. Buckle
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
- * E-mail: (AMB); (IK)
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3
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Godlewska M, Czarnocka B, Gora M. Localization of key amino acid residues in the dominant conformational epitopes on thyroid peroxidase recognized by mouse monoclonal antibodies. Autoimmunity 2012; 45:476-84. [DOI: 10.3109/08916934.2012.682667] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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4
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Creaney J, Dick IM, Yeoman D, Wong S, Robinson BWS. Auto-antibodies to β-F1-ATPase and vimentin in malignant mesothelioma. PLoS One 2011; 6:e26515. [PMID: 22022619 PMCID: PMC3195718 DOI: 10.1371/journal.pone.0026515] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 09/28/2011] [Indexed: 11/19/2022] Open
Abstract
Patients with Malignant Mesothelioma (MM) develop unidentified auto-antibodies to MM tumour antigens. This study was conducted to identify the targets of MM patient auto-antibodies in order to try to understand more of the anti-tumour response and to determine if these antibodies might be helpful for diagnosis or prognostication. Using MM patient sera in a Western immunoblott screening strategy, no common immunoreactive proteins were identified. The sera from one long-term survivor recognised a protein band of 50-60 kDa present in cell lysates from four of five MM cell lines tested. The immunoreactive proteins in this band were identified by 2D electrophoretic separation of a MM cell line protein lysate, followed by analysis of excised immunoreactive proteins on a MALDI TOF mass spectrometer and peptide mass fingerprinting. The immunoreactive proteins identified were vimentin (accession gi55977767) and the ATP synthase (F1-ATPase) beta chain (accession gi114549 and gi47606749). ELISA assays were developed for antibodies to these proteins. Neither vimentin (median and 95% CI 0.346; 0.32-0.468 for MM patients, 0.327; 0.308-0.428 for controls) nor ß-F1-ATPase (0.257; 0.221-0.453 for MM patients, 0.263; 0.22-0.35 for controls) showed significant differences in autoantibody levels between a group of MM patients and controls. Using a dichotomized antibody level (high, low) for these targets we demonstrated that vimentin antibody levels were not associated with survival. In contrast, high ß-F1-ATPase antibody levels were significantly associated with increased median survival (18 months) compared to low ß F1 ATPase antibody levels (9 months; p = 0.049). Immunohistochemical analysis on a MM tissue microarray showed cytoplasmic staining in 28 of 33 samples for vimentin and strong cytoplasmic staining in14 and weak in 16 samples for ß-F1-ATPase. Therefore antibodies to neither vimentin nor ß-F1-ATPase are useful for differential diagnosis of MM, however high antibody levels to ß-F1-ATPase may be associated with increased survival and this warrants further investigation.
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Affiliation(s)
- Jenette Creaney
- National Centre for Asbestos Related Diseases, University of Western Australia, School of Medicine and Pharmacology, Nedlands, Western Australia, Australia.
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5
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Abstract
Thyroid peroxidase (TPO) evokes high-affinity, IgG-class autoantibodies [TPO autoantibodies (TPOAbs)] and TPO-specific T cells that are markers of thyroid infiltration or implicated in thyroid destruction, respectively. A diverse repertoire of human monoclonal TPOAbs, unparalleled in other autoimmune diseases, provides invaluable probes for investigating antibody epitopes. Human TPOAbs recognize an immunodominant region comprising overlapping A and B domains on conformationally intact TPO. Amino acids recognized by TPOAbs are located in the regions with homology to myeloperoxidase (MPO) and the complement control protein (CCP) but not in the epidermal growth factor (EGF)-like region. T cells recognize epitopes in the MPO-like region but not in the CCP- or EGF-like regions in humans. Monoclonal human TPOAbs modulate processing of TPO protein to provide peptides for some T cells. A human T cell clone expressed transgenically in mice induces lymphocytic infiltration and hypothyroidism. This T cell's epitope is only generated by thyrocyte processing of endogenous TPO. Further, intact TPO expressed in vivo is also required for induction of TPOAbs in mice that resemble human autoantibodies. Overall, some TPO-specific T cells and the majority of autoantibodies in humans develop in response to TPO presented by thyroid cells, rather than to TPO released by damaged thyrocytes.
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Affiliation(s)
- Sandra M McLachlan
- Autoimmune Disease Unit, Cedars-Sinai Medical Center and UCLA Medical School, Los Angeles, California, USA.
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6
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Ananieva-Jordanova R, Evans M, Nakamatsu T, Premawardhana LDKE, Sanders J, Powell M, Chen S, McGrath V, Belton C, Arnold C, Baker S, Betterle C, Zanchetta R, Smith BR, Furmaniak J. Isolation and characterisation of a human monoclonal autoantibody to the islet cell autoantigen IA-2. J Autoimmun 2005; 24:337-45. [PMID: 15869863 DOI: 10.1016/j.jaut.2005.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Revised: 01/31/2005] [Accepted: 03/01/2005] [Indexed: 11/20/2022]
Abstract
A hybridoma secreting a human monoclonal autoantibody to the islet cell autoantigen IA-2 was prepared from peripheral lymphocytes of a patient with type 1 diabetes and Graves' disease using EBV infection followed by fusion with a mouse/human hybrid cell line. The monoclonal antibody (M13) is an IgG1/kappa and in an immunofluorescence test M13 at 1 microg/mL showed islet cell antibody reactivity equivalent to 40 JDF units. M13 IgG bound (35)S-labelled IA-2 (26% at 100 microg/mL) and (125)I-labelled IA-2 (34% at 100 microg/mL) in an immunoprecipitation assay and reacted well with IA-2 in western blotting analysis. Amino acids 777-808 in the PTP domain of IA-2 were found to be important for M13 binding in an analysis using modified (35)S-labelled IA-2 proteins. M13 V region genes were from VH1-3, D3-22, JH4b, VKI DPK8/Vd+ and JK3 genes and showed a high replacement/silent mutation ratio for both the heavy (11.0) and the light (6.0) chain genes. Mouse monoclonal antibodies (mMAbs) reactive with at least three different epitopes within IA-2 aa 604-686 corresponding to the juxtamembrane domain were also obtained. F(ab')(2) or Fab from the mMAbs inhibited serum IA-2 autoantibody binding to IA-2 in 20/22 diabetic sera whereas M13 F(ab')(2) caused inhibition in only 6/22 sera. M13 is representative of some patient serum IA-2 autoantibodies and as such provides a useful tool to study autoimmune responses to IA-2.
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Bresson D, Rebuffat SA, Péraldi-Roux S. Localization of the immunodominant region on human thyroid peroxidase in autoimmune thyroid diseases: an update. JOURNAL OF AUTOIMMUNE DISEASES 2005; 2:2. [PMID: 15769293 PMCID: PMC1084359 DOI: 10.1186/1740-2557-2-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Accepted: 03/15/2005] [Indexed: 11/10/2022]
Abstract
Recent studies in the field of autoimmune thyroid diseases have largely focused on the delineation of B-cell auto-epitopes recognized by the main autoantigens to improve our understanding of how these molecules are seen by the immune system. Among these autoantigens which are targeted by autoantibodies during the development of autoimmune thyroid diseases, thyroid peroxidase is a major player. Indeed, high amounts of anti-thyroid peroxidase autoantibodies are found in the sera of patients suffering from Graves' disease and Hashimoto's thyroiditis, respectively hyper and hypothyroidism. Since anti-thyroid peroxidase autoantibodies from patients'sera mainly recognize a discontinuous immunodominant region on thyroid peroxidase and due to the complexity of the three dimensional structure of human thyroid peroxidase, numerous investigations have been necessary to closely localize this immunodominant region. The aim of the present review is to summarize the current knowledge regarding the localization of the immunodominant region recognized by human thyroid peroxidase-specific autoantibodies generated during the development of autoimmune thyroid diseases.
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Affiliation(s)
- Damien Bresson
- CNRS UMR 5160, Centre de Pharmacologie et Biotechnologie pour la Santé, Faculté de Pharmacie, 15 avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 5, France
- La Jolla Institute for Allergy and Immunology, Department of Developmental Immunology-3, 10355 Science Center Drive, San Diego, CA 92121, USA
| | - Sandra A Rebuffat
- CNRS UMR 5160, Centre de Pharmacologie et Biotechnologie pour la Santé, Faculté de Pharmacie, 15 avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 5, France
| | - Sylvie Péraldi-Roux
- CNRS UMR 5160, Centre de Pharmacologie et Biotechnologie pour la Santé, Faculté de Pharmacie, 15 avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 5, France
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8
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Bresson D, Pugnière M, Roquet F, Rebuffat SA, N-Guyen B, Cerutti M, Guo J, McLachlan SM, Rapoport B, Estienne V, Ruf J, Chardès T, Péraldi-Roux S. Directed Mutagenesis in Region 713-720 of Human Thyroperoxidase Assigns 713KFPED717 Residues as Being Involved in the B Domain of the Discontinuous Immunodominant Region Recognized by Human Autoantibodies. J Biol Chem 2004; 279:39058-67. [PMID: 15150267 DOI: 10.1074/jbc.m403897200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Autoantibodies (aAbs) to thyroid peroxidase (TPO), the hallmark of autoimmune thyroid disease (AITD), recognize conformational epitopes restricted to an immunodominant region (IDR), divided into two overlapping domains A and B. Despite numerous efforts aimed at localizing the IDR and identifying aAb-interacting residues on TPO, only two critical amino acids, Lys(713) and Tyr(772), have been characterized. Precise and complete delineation of the other residues involved in the IDR remains to be defined. By using a recombinant anti-TPO aAb T13, we demonstrated that four regions on TPO are part of the IDR/B; one of them, located between amino acids 713 and 720, is particularly important for the binding of sera from patients suffering from AITD. To precisely define critical residues implicated in the binding of aAb to human TPO, we used directed mutagenesis and expressed the mutants in stably transfected CHO cells. Then we assessed the kinetic parameters involved in the interactions between anti-TPO aAbs and mutants by real-time analysis. We identified (i) the minimal epitope 713-717 recognized by mAb 47 (a reference antibody) and (ii) the amino acids used as contact points for two IDR-specific human monoclonal aAbs TR1.9 (Pro(715) and Asp(717)) and T13 (Lys(713), Phe(714), Pro(715), and Glu(716)). Using a rational strategy to identify complex epitopes on proteins showing a highly convoluted architecture, this study definitively identifies the amino acids Lys(713)-Asp(717) as being the key residues recognized by IDR/B-specific anti-TPO aAbs in AITD.
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Affiliation(s)
- Damien Bresson
- CNRS UMR 5160, Centre de Pharmacologie et Biotechnologie pour la Santé, Faculté de Pharmacie, 15 avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 5, France
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9
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Gora M, Gardas A, Wiktorowicz W, Hobby P, Watson PF, Weetman AP, Sutton BJ, Banga JP. Evaluation of conformational epitopes on thyroid peroxidase by antipeptide antibody binding and mutagenesis. Clin Exp Immunol 2004; 136:137-44. [PMID: 15030525 PMCID: PMC1809007 DOI: 10.1111/j.1365-2249.2004.02422.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Autoantibodies to thyroid peroxidase (TPO) recognize predominantly conformational epitopes, which are restricted to two distinct determinants, termed immunodominant domain region (IDR) A and B. These dominant determinants reside in the region with structural homology to myeloperoxidase (MPO)-like domain and may extend into the adjacent complement control protein (CCP) domain. We have explored the location of these determinants on the MPO-like domain of the structural model of TPO, by identifying exposed hydrophilic loops that are potential candidates for the autoantigenic sites, generating rabbit antipeptide antisera, and competing with well characterized murine monoclonal antibodies (mabs) specific for these two IDRs. We recently defined the location of IDR-B, and here report our findings on the location of IDR-A and its relationship to IDR-B, defined with a new panel of 15 antipeptide antisera. Moreover, in combination with single amino acid replacements by in vitro mutagenesis, we have defined the limits of the IDR-B region on the TPO model. The combination of antisera to peptides P12 (aa 549-563), P14 (aa 599-617) and P18 (aa 210-225) inhibited the binding of the mab specific for IDR-A (mab 2) by 75%. The same combination inhibited the binding of autoantibodies to native TPO from 67 to 94% (mean 81.5%) at autoantibody levels of 5 IU. Fabs prepared from the antipeptide IgG and pooled in this combination were also effective in competition assays, thus defining the epitopes more precisely. IDR-A was found to lie immediately adjacent to IDR-B and thus the two immunodominant epitopes form an extended patch on the surface of TPO. Finally, by single amino acid mutagenesis, we show that IDR-B extends to residue N642, thus further localizing the boundary of this autoantigenic region on the structural model.
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Affiliation(s)
- M Gora
- Medical Centre of Postgraduate Education, Warsaw, Poland
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10
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Bresson D, Cerutti M, Devauchelle G, Pugnière M, Roquet F, Bes C, Bossard C, Chardès T, Péraldi-Roux S. Localization of the discontinuous immunodominant region recognized by human anti-thyroperoxidase autoantibodies in autoimmune thyroid diseases. J Biol Chem 2003; 278:9560-9. [PMID: 12501244 DOI: 10.1074/jbc.m211930200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The discontinuous immunodominant region (IDR) recognized by autoantibodies directed against the thyroperoxidase (TPO) molecule, a major autoantigen in autoimmune thyroid diseases, has not yet been completely localized. By using peptide phage-displayed technology, we identified three critical motifs, LXPEXD, QSYP, and EX(E/D)PPV, within selected mimotopes which interacted with the human recombinant anti-TPO autoantibody (aAb) T13, derived from an antibody phage-displayed library obtained from thyroid-infiltrating TPO-selected B cells of Graves' disease patients. Mimotope sequence alignment on the TPO molecule, together with the binding analysis of the T13 aAb on TPO mutants expressed by Chinese hamster ovary cells, demonstrated that regions 353-363, 377-386, and 713-720 from the myeloperoxidase-like domain and region 766-775 from the complement control protein-like domain are a part of the IDR recognized by the recombinant aAb T13. Furthermore, we demonstrated that these regions were involved in the binding to TPO of sera containing TPO-specific autoantibodies from patients suffering from Hashimoto's and Graves' autoimmune diseases. Identification of the IDR could lead to improved diagnosis of thyroid autoimmune diseases by engineering "mini-TPO" as a target autoantigen or designing therapeutic peptides able to block undesired autoimmune responses.
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MESH Headings
- Alanine/chemistry
- Amino Acid Motifs
- Amino Acid Sequence
- Animals
- Antibodies/chemistry
- Antibodies, Monoclonal/metabolism
- Autoantibodies/chemistry
- Autoimmune Diseases/immunology
- B-Lymphocytes/metabolism
- Binding, Competitive
- Blotting, Western
- Cell Line
- Cell Membrane/metabolism
- Cloning, Molecular
- Dose-Response Relationship, Drug
- Dose-Response Relationship, Immunologic
- Enzyme-Linked Immunosorbent Assay
- Epitopes
- Graves Disease/immunology
- Graves Disease/metabolism
- Humans
- Immunoassay
- Immunodominant Epitopes
- Insecta
- Iodide Peroxidase/chemistry
- Iodide Peroxidase/immunology
- Kinetics
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Mutation
- Peptide Library
- Peptides/chemistry
- Protein Binding
- Protein Denaturation
- Protein Structure, Tertiary
- Recombinant Proteins/chemistry
- Sequence Homology, Amino Acid
- Thyroid Diseases/immunology
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Affiliation(s)
- Damien Bresson
- CNRS Unité Mixte de Recherche (UMR) 5094, Faculté de Pharmacie, 15 avenue Charles Flahault, B. P. 14491, Montpellier 34093 Cedex 5, France.
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11
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Pichurin PN, Guo J, Estienne V, Carayon P, Ruf J, Rapoport B, McLachlan SM. Evidence that the complement control protein-epidermal growth factor-like domain of thyroid peroxidase lies on the fringe of the immunodominant region recognized by autoantibodies. Thyroid 2002; 12:1085-95. [PMID: 12593722 DOI: 10.1089/105072502321085180] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
There is no consensus regarding the location of the immunodominant region (IDR) on thyroid peroxidase (TPO) recognized by the majority of autoantibodies. Strong evidence indicates that it lies upstream of amino acid 741. However, an epitope has been localized to downstream residues 742-848 encompassing a disulfide-rich complement control protein (CCP)-like and epidermal growth factor (EGF)-like domain. To determine whether these domains comprise part of the IDR, we used a recombinant CCP/EGF-like polypeptide to screen a thyroid B-cell-derived immunoglobulin gene phage display library. Two unusual TPO autoantibodies were isolated. Neither was among the 83 clones previously obtained by panning the same library on native or denatured TPO, or TPO with the IDR masked. Fab from these clones bound native TPO, one with high affinity (Kd 6 x 10(-10) M), and both recognized TPO expressed on the surface of mammalian cells. Phage-expressing multiple copies of the antibody (multivalent), but not monovalent Fab from these clones, bound to the CCP/EGF polypeptide. Most important, inhibition of TPO binding by autoantibodies to the IDR indicated that the epitopes of the two new autoantibodies overlap with this region. The value of these two rare clones lies in the insight they provide into the location of the TPO IDR. From their binding characteristics, we deduce that the CCP/EGF-like domain lies on the fringe of the TPO immunodominant region.
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Affiliation(s)
- Pavel N Pichurin
- Autoimmune Disease Unit, Cedars-Sinai Research Institute, Los Angeles, California, USA
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12
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Guo J, McLachlan SM, Rapoport B. Localization of the thyroid peroxidase autoantibody immunodominant region to a junctional region containing portions of the domains homologous to complement control protein and myeloperoxidase. J Biol Chem 2002; 277:40189-95. [PMID: 12167622 DOI: 10.1074/jbc.m205524200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thyroid peroxidase (TPO) autoantibody epitopes are largely restricted to an immunodominant region (IDR) on the extracellular region of the native molecule. Localization of the IDR has been a longstanding and difficult goal. The TPO extracellular region comprises a large myeloperoxidase-like domain, linked to the plasma membrane by two smaller domains with homology to complement control protein (CCP) and epidermal growth factor (EGF), respectively. Recent studies have focused on the CCP- and EGF-like domains as the putative location of the TPO autoantibody IDR. To address this issue, we attempted to express on the surface of transfected cells native TPO in which the CCP- and EGF-like domains were deleted, either together or individually. We used a quartet of human monoclonal autoantibodies that define the TPO IDR, as well as polyclonal TPO autoantibodies in patients' sera, to detect these mutated TPO molecules by flow cytometry. The combined CCP/EGF-like domain deletion did not produce a signal with TPO autoantibodies but did not traffic to the cell surface. In contrast, both monoclonal and polyclonal autoantibodies recognized TPO with the juxtamembrane EGF-like domain deleted equally as well as the wild-type TPO on the cell surface. TPO with the CCP-like domain deleted expressed normally on the cell surface, as determined using the polyclonal mouse antiserum. Nevertheless, this modified TPO molecule was recognized very poorly by both the human monoclonal autoantibodies and the polyclonal autoantibodies in patients' sera. In conclusion, we have clearly excluded the juxtamembrane EGF-like domain as being part of the IDR. In contrast, a component of the CCP-like domain does contribute to the IDR. These data, together with findings from other studies, localize the TPO autoantibody IDR to the junction of the CCP-like domain and the much larger myeloperoxidase-like domain on TPO.
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Affiliation(s)
- Jin Guo
- Autoimmune Disease Unit, Medical Center, Cedars-Sinai Research Institute, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
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13
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Tozzoli R, Bizzaro N, Tonutti E, Pradella M, Manoni F, Vilalta D, Bassetti D, Piazza A, Rizzotti P. Immunoassay of anti-thyroid autoantibodies: high analytical variability in second generation methods. Clin Chem Lab Med 2002; 40:568-73. [PMID: 12211650 DOI: 10.1515/cclm.2002.098] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The use of highly sensitive immunometric methods in clinical laboratories to assay anti-thyroid antibodies has progressively expanded in recent years but it is not known whether the new techniques have improved the analytical variability connected with the preceding methodologies. The Italian Society of Laboratory Medicine Study Group on Autoimmune Diseases conducted a collaborative study with the biomedical industry to evaluate the degree of standardization of the new analytical procedures. Twelve companies agreed to participate in the study on the search for anti-thyroglobulin (anti-Tg) and anti-thyroperoxidase (anti-TPO) antibodies in nine sera from patients with autoimmune thyroiditis, and in six sera from patients with non-autoimmune thyroid disease; ten immunometric and three immunofluorescence methods were employed. Agreement of qualitative results was close to 90% for anti-Tg and 97% for anti-TPO, with no important differences between the methods; variability of the quantitative results, expressed as CV% of absolute (in lU/ml) and relative (in cut-off concentration multiples) values was 93.9% and 102.3%, respectively, for anti-Tg, and 75.5% and 62.9%, respectively, for anti-TPO. These findings show that despite the progressive improvement in the analytical techniques, the variability between methods for the assay of anti-Tg and anti-TPO is still unexpectedly high, and probably due to several factors such as uncertainty in defining the positive cutoff concentration, absence of adequate international reference preparations, modality of autoantigen purification, and analytical variability in the assay procedures.
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Affiliation(s)
- Renato Tozzoli
- Laboratorio Analisi Chimico-cliniche e Microbiologia, Ospedale Civile, Latisana, UD, Italy
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14
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Estienne V, Duthoit C, Blanchin S, Montserret R, Durand-Gorde JM, Chartier M, Baty D, Carayon P, Ruf J. Analysis of a conformational B cell epitope of human thyroid peroxidase: identification of a tyrosine residue at a strategic location for immunodominance. Int Immunol 2002; 14:359-66. [PMID: 11934872 DOI: 10.1093/intimm/14.4.359] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Thyroid peroxidase (TPO) is involved in autoimmune thyroid diseases and high titers of TPO autoantibodies directed to various conformational B cell epitopes are frequently present in patients' sera. Deciphering these epitopes is a difficult task, but can give insight into the structural basis of autoimmune recognition. TPO is a membrane-bound enzyme with the extracellular part organized in three protein domains, but of unknown three-dimensional structure. We previously localized a TPO B cell epitope within amino acid residues 742-848, a region encompassing the two C-terminal, extracellular domains of the protein. We found that at least one of the three tyrosine residues of the peptide 742-848 might be involved in autoantibody binding. In this study, we show by site-directed mutagenesis that the autoepitope contains tyrosine 772 located near the hinge area between the two protein domains, suggesting they are both involved in the epitope structure. The B cell epitopes of TPO are clustered in two overlapping immunodominant regions. To map the newly localized epitope with respect of these regions, competition experiments were performed using a reference panel of TPO mAb and a further mAb previously found to be specific for the TPO peptide 742-848 at variance with all the other ones. Here, we show that the tyrosine 772-bearing epitope in the peptide 742-848 maps in a region that partly overlaps the reported two immunodominant regions. These results are suggestive of a complex TPO folding that involves all the three TPO protein domains to form a highly conformational immunodominant region.
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Affiliation(s)
- Valérie Estienne
- U555 INSERM/Laboratoire de Biochimie Endocrinienne et Métabolique, Faculté de Médecine, Université de la Méditerranée, 13385 Marseille Cedex 05, France
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15
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Hendry E, Taylor G, Grennan-Jones F, Sullivan A, Liddy N, Godfrey J, Hayakawa N, Powell M, Sanders J, Furmaniak J, Smith BR. X-ray crystal structure of a monoclonal antibody that binds to a major autoantigenic epitope on thyroid peroxidase. Thyroid 2001; 11:1091-9. [PMID: 12186495 DOI: 10.1089/10507250152740920] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Thyroid peroxidase (TPO) catalyzes the production of thyroid hormones and is a major autoantigen in autoimmune thyroid disease (AITD). It is believed that the majority of TPO autoantibodies bind to an immunodominant region consisting of two overlapping domains. Precise location of these domains would help our understanding of the interaction between TPO and TPO autoantibodies. 4F5 is a mouse monoclonal antibody (IgG1, kappa) that reacts with high affinity (2.6 x 10(10) mol/L(-1)) with one of the major autoantigenic regions on TPO. Heavy chain genes of 4F5 were from the VH1 germline gene family, germline genes for the D region could not be assigned and the J region was from the JH2 germline. Light chain genes were from Vkappa4/5 and Jkappa2, germline gene families. The Fab fragment of 4F5 was prepared by papain digestion, purified, crystallized, and the structure solved to 1.9 A using molecular replacement. The refined structure had an R factor of 19.5% and a free R factor of 23.9%. Deduced amino acid sequence and amino acid sequence obtained from diffraction analysis were compared and used to finalize the 4F5 Fab model. Structural analysis indicated that the structure of 4F5 is that of a standard Fab and its combining site is flat and is rich in tyrosine residues. Comparison of the structure of 4F5 with that of a TPO autoantibody Fab, TR1.9 suggests that the two antibodies are unlikely to recognise the same structures on TPO.
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Affiliation(s)
- E Hendry
- The Centre for Biomolecular Sciences, University of St Andrews, Fife, United Kingdom
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16
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Xiong Z, Farilla L, Guo J, McLachlan S, Rapoport B. Does the autoantibody immunodominant region on thyroid peroxidase include amino acid residues 742-771? Thyroid 2001; 11:227-31. [PMID: 11327613 DOI: 10.1089/105072501750159598] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Identification of the thyroid peroxidase (TPO) amino acid residues that comprise the autoantibody immunodominant region is an important goal that has proven difficult because of the conformational nature of the epitopes involved. Recent data suggest that the immunodominant region has been located. Thus, by autoantibody recognition of tryptic fragments of native TPO, as well as of conformational portions of TPO expressed as cell-free translates, the autoantibody immunodominant region appears to include amino acid residues 742-771, near the C terminus of the ectodomain. To evaluate this deduction, we expressed as cell-free translates the full TPO ectodomain, as well as TPO truncated after residues 741 and 771. The epitopic integrity of these molecules was first confirmed by immunoprecipitation by patient sera containing TPO autoantibodies. However, autoantibody recognition could involve a minority of TPO autoantibodies with the individual sera, not fulfilling the strict criteria for immunodominance. In order to obtain definitive data, we performed immunoprecipitations on these TPO variants with four recombinant human monoclonal autoantibodies that define the immunodominant region. All four monoclonal autoantibodies immunoprecipitated TPO 1-741 to the same extent as they did TPO 1-771 and the full TPO ectodomain, indicating that the immunodominant region comprises (at least in large part) amino acid residues upstream of residue 741.
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Affiliation(s)
- Z Xiong
- Autoimmune Disease Unit, Cedars-Sinai Research Institute and School of Medicine, University of California, Los Angeles, USA
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Gardas A, Watson PF, Hobby P, Smith A, Weetman AP, Sutton BJ, Banga JP. Human thyroid peroxidase: mapping of autoantibodies, conformational epitopes to the enzyme surface. Redox Rep 2001; 5:237-41. [PMID: 10994879 DOI: 10.1179/135100000101535681] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The enzyme, thyroid peroxidase (TPO), is a dominant antigen in thyroid autoimmune diseases. Autoantibodies recognised two major dominant conformational epitopes termed A and B. The epitopes have been defined by mAbs, but the amino acid residues which constitute these determinants remain unknown. Using a model of TPO, built from the structure of myeloperoxidase (MPO), we have synthesised peptides corresponding to exposed loops and generated rabbit antibodies to the peptides. Antisera to peptide sequence 599-617 (peptide 14) representing a highly protrusive loop on the TPO, showed the highest inhibition in 65 sera from patients positive with anti-TPO antibodies. The inhibition was by 15-80% (mean 41%), and no other antibody showed any inhibition. Binding of hFabs to the B determinant on TPO was inhibited by anti-peptide 14 antibodies more then 85%, but not Fabs to the A determinant. In conclusion, the peptide 14 defines a sequence taking part in building up the B major conformational epitope. None of generated anti-peptide antibodies alone inhibited the binding of human Fabs to the A epitope, however a combination of four anti-peptide antibodies (P1, P12, P14 and P18) inhibits Fabs binding to the A determinant by more then 60% and autoantibodies binding from 65% to 94%. Combination of antibodies reacting with peptides outside the surface defined by those four antipeptide antibodies did not give any inhibition of Fabs to TPO. The inhibition of Fabs and auto Abs to TPO by this combination of anti-peptide Abs is the result of steric hindrance as none of these Abs individually inhibited auto Abs' or Fabs' binding to TPO. The four peptides define an area on the enzyme surface where the A and B major conformational epitopes are localised.
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Affiliation(s)
- A Gardas
- Medical Centre of Postgraduate Education, Warsaw, Poland
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Guo J, Yan XM, McLachlan SM, Rapoport B. Search for the autoantibody immunodominant region on thyroid peroxidase: epitopic footprinting with a human monoclonal autoantibody locates a facet on the native antigen containing a highly conformational epitope. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:1327-33. [PMID: 11145717 DOI: 10.4049/jimmunol.166.2.1327] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Autoantibodies to thyroid peroxidase (TPO) are the hallmark of the humoral autoimmune response in human autoimmune thyroiditis (Hashimoto's thyroiditis). The majority of TPO autoantibodies in individual patients' sera interact with a restricted immunodominant region on TPO. Although this region can be mapped, previous studies have failed to localize its position on the TPO molecule. We, therefore, used a footprinting approach that can localize a highly conformational, discontinuous epitope on a very large molecule. Extensive biotinylation ( approximately 15 biotins/molecule protein) of lysine residues on the surface of purified, native TPO resulted in loss of multiple tryptic cleavage sites, as determined by analysis of tryptic polypeptide fragments on reverse-phase HPLC. TPO was then complexed with a monoclonal human autoantibody Fab (TR1.9) before biotinylation. After dissociation from TR1.9, TPO was recovered by gel filtration. A trypsin site, previously observed to be lost after TPO biotinylation, was restored when biotinylation was performed on the TPO-TR1.9 complex. The epitope-protected lysine (K) was present in a 30-aa TPO fragment that, by N-terminal sequencing, was found to be K713. Altered recognition by TR1.9 of a TPO-myeloperoxidase chimeric molecule involving this region supported the epitope protection data. In conclusion, we provide the first identification of an amino acid residue (K713) comprising part of an epitope within the TPO immunodominant region. This focal residue localizes the facet on the large, highly complex TPO molecule that contains the immunodominant region and provides the basis for rational guided mutagenesis studies to more fully characterize this region.
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Affiliation(s)
- J Guo
- Autoimmune Disease Unit, Cedars-Sinai Research Institute, and University of California School of Medicine, Los Angeles, CA 90048, USA
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