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Williams DE, Le SN, Hoke DE, Chandler PG, Gora M, Godlewska M, Banga JP, Buckle AM. Structural Studies of Thyroid Peroxidase Show the Monomer Interacting With Autoantibodies in Thyroid Autoimmune Disease. Endocrinology 2020; 161:5727781. [PMID: 32022847 DOI: 10.1210/endocr/bqaa016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/04/2020] [Indexed: 01/17/2023]
Abstract
Thyroid peroxidase (TPO) is a critical membrane-bound enzyme involved in the biosynthesis of multiple thyroid hormones, and is a major autoantigen in autoimmune thyroid diseases such as destructive (Hashimoto) thyroiditis. Here we report the biophysical and structural characterization of a novel TPO construct containing only the ectodomain of TPO and lacking the propeptide. The construct was enzymatically active and able to bind the patient-derived TR1.9 autoantibody. Analytical ultracentrifugation data suggest that TPO can exist as both a monomer and a dimer. Combined with negative stain electron microscopy and molecular dynamics simulations, these data show that the TR1.9 autoantibody preferentially binds the TPO monomer, revealing conformational changes that bring together previously disparate residues into a continuous epitope. In addition to providing plausible structural models of a TPO-autoantibody complex, this study provides validated TPO constructs that will facilitate further characterization, and advances our understanding of the structural, functional, and antigenic characteristics of TPO, an autoantigen implicated in some of the most common autoimmune diseases.
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Affiliation(s)
- Daniel E Williams
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Sarah N Le
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts
| | - David E Hoke
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Peter G Chandler
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Monika Gora
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Marlena Godlewska
- Department of Biochemistry and Molecular Biology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - J Paul Banga
- Emeritus, King's College London, London WC2R 2LS, United Kingdom
| | - Ashley M Buckle
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
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Godlewska M, Banga PJ. Thyroid peroxidase as a dual active site enzyme: Focus on biosynthesis, hormonogenesis and thyroid disorders of autoimmunity and cancer. Biochimie 2019; 160:34-45. [DOI: 10.1016/j.biochi.2019.02.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 02/05/2019] [Indexed: 01/02/2023]
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McLachlan SM, Rapoport B. Thyroid Autoantibodies Display both "Original Antigenic Sin" and Epitope Spreading. Front Immunol 2017; 8:1845. [PMID: 29326719 PMCID: PMC5742354 DOI: 10.3389/fimmu.2017.01845] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/06/2017] [Indexed: 11/13/2022] Open
Abstract
Evidence for original antigenic sin in spontaneous thyroid autoimmunity is revealed by autoantibody interactions with immunodominant regions on thyroid autoantigens, thyroglobulin (Tg), thyroid peroxidase (TPO), and the thyrotropin receptor (TSHR) A-subunit. In contrast, antibodies induced by immunization of rabbits or mice recognize diverse epitopes. Recognition of immunodominant regions persists despite fluctuations in autoantibody levels following treatment or over time. The enhancement of spontaneously arising pathogenic TSHR antibodies in transgenic human thyrotropin receptor/NOD.H2h4 mice by injecting a non-pathogenic form of TSHR A-subunit protein also provides evidence for original antigenic sin. From other studies, antigen presentation by B cells, not dendritic cells, is likely responsible for original antigenic sin. Recognition of restricted epitopes on the large glycosylated thyroid autoantigens (60-kDa A-subunit, 100-kDa TPO, and 600-kDa Tg) facilitates exploring the amino acid locations in the immunodominant regions. Epitope spreading has also been revealed by autoantibodies in thyroid autoimmunity. In humans, and in mice that spontaneously develop autoimmunity to all three thyroid autoantigens, autoantibodies develop first to Tg and later to TPO and the TSHR A-subunit. The pattern of intermolecular epitope spreading is related in part to the thyroidal content of Tg, TPO and TSHR A-subunit and to the molecular sizes of these proteins. Importantly, the epitope spreading pattern provides a rationale for future antigen-specific manipulation to block the development of all thyroid autoantibodies by inducing tolerance to Tg, first in the autoantigen cascade. Because of its abundance, Tg may be the autoantigen of choice to explore antigen-specific treatment, preventing the development of pathogenic TSHR antibodies.
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Affiliation(s)
- Sandra M McLachlan
- Thyroid Autoimmune Disease Unit, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA, United States
| | - Basil Rapoport
- Thyroid Autoimmune Disease Unit, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA, United States
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Godlewska M, Arczewska KD, Rudzińska M, Łyczkowska A, Krasuska W, Hanusek K, Ruf J, Kiedrowski M, Czarnocka B. Thyroid peroxidase (TPO) expressed in thyroid and breast tissues shows similar antigenic properties. PLoS One 2017; 12:e0179066. [PMID: 28575127 PMCID: PMC5456382 DOI: 10.1371/journal.pone.0179066] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/23/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Thyroid peroxidase (TPO) is essential for physiological function of the thyroid gland. The high prevalence of thyroid peroxidase antibodies (TPOAbs) in patients with breast cancer and their protective role had previously been demonstrated, indicating a link between breast cancer and thyroid autoimmunity. Recently, TPO was shown to be present in breast cancer tissue samples but its antigenicity has not been analyzed. METHODS In this study, we investigated TPO expression levels in a series of fifty-six breast cancer samples paired with normal (peri-tumoral) tissue and its antigenic activity using a panel of well-characterized murine anti-human TPOAbs. RESULTS We have shown that TPO transcripts were present in both normal and cancer tissue samples, although the amounts in the latter were reduced. Additionally, we observed that TPO levels are lower in more advanced cancers. TPO protein expression was confirmed in all tissue samples, both normal and cancerous. We also found that the antigenicity of the immunodominant regions (IDRs) in breast TPO resembles that of thyroid TPO, which is crucial for effective interactions with human TPOAbs. CONCLUSIONS Expression of TPO in breast cancer together with its antigenic activity may have beneficial effects in TPOAb-positive breast cancer patients. However, further studies are needed to confirm the beneficial role of TPOAbs and to better understand the underlying mechanism.
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Affiliation(s)
- Marlena Godlewska
- Department of Biochemistry and Molecular Biology, Center of Postgraduate Medical Education, Warsaw, Poland
| | - Katarzyna D. Arczewska
- Department of Biochemistry and Molecular Biology, Center of Postgraduate Medical Education, Warsaw, Poland
| | - Magdalena Rudzińska
- Department of Biochemistry and Molecular Biology, Center of Postgraduate Medical Education, Warsaw, Poland
| | - Anna Łyczkowska
- Department of Biochemistry and Molecular Biology, Center of Postgraduate Medical Education, Warsaw, Poland
| | - Wanda Krasuska
- Department of Biochemistry and Molecular Biology, Center of Postgraduate Medical Education, Warsaw, Poland
| | - Karolina Hanusek
- Department of Biochemistry and Molecular Biology, Center of Postgraduate Medical Education, Warsaw, Poland
| | - Jean Ruf
- UMR-MD2, Aix-Marseille University, Marseille Medical School, Marseille, France
| | - Mirosław Kiedrowski
- Clinical Department of Oncology and Hematology, Central Clinical Hospital of the Ministry of Interior in Warsaw, Warsaw, Poland
| | - Barbara Czarnocka
- Department of Biochemistry and Molecular Biology, Center of Postgraduate Medical Education, Warsaw, Poland
- * E-mail:
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Godlewska M, Góra M, Buckle AM, Porebski BT, Kemp EH, Sutton BJ, Czarnocka B, Banga JP. A redundant role of human thyroid peroxidase propeptide for cellular, enzymatic, and immunological activity. Thyroid 2014; 24:371-82. [PMID: 23668778 PMCID: PMC3926150 DOI: 10.1089/thy.2013.0127] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Thyroid peroxidase (TPO) is a dimeric membrane-bound enzyme of thyroid follicular cells, responsible for thyroid hormone biosynthesis. TPO is also a common target antigen in autoimmune thyroid disease (AITD). With two active sites, TPO is an unusual enzyme, and thus there is much interest in understanding its structure and role in AITD. Homology modeling has shown TPO to be composed of different structural modules, as well as a propeptide sequence. During the course of studies to obtain homogeneous preparations of recombinant TPO for structural studies, we investigated the role of the large propeptide sequence in TPO. METHODS An engineered recombinant human TPO preparation expressed in Chinese hamster ovary (CHO) cells lacking the propeptide (TPOΔpro; amino acid residues 21-108) was characterized and its properties compared to wild-type TPO. Plasma membrane localization was determined by cell surface protein biotinylation, and biochemical studies were performed to evaluate enzymatic activity and the effect of deglycosylation. Immunological investigations using autoantibodies from AITD patients and other epitope-specific antibodies that recognize conformational determinants on TPO were evaluated for binding to TPOΔpro by flow cytometry, immunocytochemistry, and capture enzyme-linked immunosorbent assay. Molecular modeling and dynamics simulation of TPOΔpro comprising a dimer of myeloperoxidase-like domains was performed in order to investigate the impact of propeptide removal and the role of glycosylation. RESULTS The TPOΔpro was expressed on the cell surface at comparable levels to wild-type TPO. The TPOΔpro was enzymatically active and recognized by patients' autoantibodies and a panel of epitope-specific antibodies, confirming structural integrity of the two major conformational determinants recognized by autoantibodies. Faithful intracellular trafficking and N-glycosylation of TPOΔpro was also maintained. Molecular modeling and dynamics simulations were consistent with these observations. CONCLUSIONS Our results point to a redundant role for the propeptide sequence in TPO. The successful expression of TPOΔpro in a membrane-anchored, enzymatically active form that is insensitive to intramolecular proteolysis, and importantly is recognized by patients' autoantibodies, is a key advance for purification of substantial quantities of homogeneous preparation of TPO for crystallization, structural, and immunological studies.
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Affiliation(s)
- Marlena Godlewska
- Department of Biochemistry and Molecular Biology, Medical Center of Postgraduate Education, Warsaw, Poland
| | - Monika Góra
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Ashley M. Buckle
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Monash University, Clayton, Australia
| | - Benjamin T. Porebski
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Monash University, Clayton, Australia
| | - E. Helen Kemp
- Department of Human Metabolism, School of Medicine, University of Sheffield, Sheffield, United Kingdom
| | - Brian J. Sutton
- Randall Division of Cell & Molecular Biophysics, King's College London, London, United Kingdom
| | - Barbara Czarnocka
- Department of Biochemistry and Molecular Biology, Medical Center of Postgraduate Education, Warsaw, Poland
| | - J. Paul Banga
- Division of Diabetes and Nutritional Sciences, School of Medicine, King's College London, London, United Kingdom
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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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Human recombinant anti-thyroperoxidase autoantibodies: in vitro cytotoxic activity on papillary thyroid cancer expressing TPO. Br J Cancer 2010; 102:852-61. [PMID: 20145622 PMCID: PMC2833240 DOI: 10.1038/sj.bjc.6605464] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background: Thyroid cancers are difficult to treat due to their limited responsiveness to chemo- and radiotherapy. There is thus a great interest in and a need for alternative therapeutic approaches. Results: We studied the cytotoxic activity of anti-thyroperoxidase autoantibodies (anti-TPO aAbs, expressed in baculovirus/insect cell (B4) and CHO cells (B4′) or purified from patients' sera) against a papillary thyroid cancer (NPA) cell line. Anti-TPO aAbs from patients' sera led to a partial destruction of NPA cell line by complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC) and exhibited an anti-proliferative activity. Comparison of the cytotoxic activity of anti-TPO aAbs shows that B4′ induced an anti-proliferative effect and a better ADCC than B4, but a lower one than anti-TPO aAbs from patients' sera. Antibody-dependent cell-mediated cytotoxicity was increased when human peripheral blood mononuclear cells were used as effector cells, suggesting that FcγRs, CD64, CD32 and CD16 are involved. Indeed, anti-TPO aAbs from patients' sera, but not B4 and B4′, exhibited CDC activity. Conclusions: These data indicate that anti-TPO aAbs display moderate ADCC and anti-proliferative activities on NPA cells; IgG glycosylation appears to be important for cytotoxic activity and ADCC efficiency depends on FcγR-bearing cells. Finally, recombinant human anti-TPO aAbs cannot yet be considered as an optimal tool for the development of a novel therapeutic approach for thyroid cancer.
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Nielsen CH, Brix TH, Gardas A, Banga JP, Hegedüs L. Epitope recognition patterns of thyroid peroxidase autoantibodies in healthy individuals and patients with Hashimoto's thyroiditis*. Clin Endocrinol (Oxf) 2008; 69:664-8. [PMID: 18363888 DOI: 10.1111/j.1365-2265.2008.03245.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Thyroid peroxidase antibodies (TPOAb) are markers of autoimmune thyroid disease (AITD), including Hashimoto's thyroiditis (HT), but naturally occurring TPOAb are also detectable in healthy, euthyroid individuals. In AITD, circulating TPOAb react mainly with two immunodominant regions (IDR), IDR-A and IDR-B. The present study was undertaken in order to compare the epitope recognition pattern of TPOAb in HT patients and healthy subjects. DESIGN Sera from 21 out of 98 healthy controls were selected on the basis of high TPOAb values, required for determination of TPOAb recognition pattern; as were sera from 92 HT patients. MEASUREMENTS Measurement of IDR-reactivity was possible in 90 patients and 12 controls. IDR-A-, IDR-B- and non-IDR-A/non-IDR-B-Ab constituted 24 +/- 11%, 50 +/- 15% and 26 +/- 12%, respectively, in the patients. The distribution in the controls was distinctly different, only 12 +/- 13% being directed against IDR-A (P < 0.002) and 66 +/- 22% against IDR-B (P < 0.002). Half of the healthy individuals, vs. none of the HT patients, lacked IDR-A reactivity completely (P < 0.0001). In HT patients, IDR-B-Ab proportions increased slightly with increasing TPOAb levels (P < 0.05), while IDR-B-Ab of the controls showed a strong opposite trend (P < 0.0001). Accordingly, the proportion of non-A/non-B-Ab correlated with TPOAb levels in the healthy controls (P < 0.008), and an inverse correlation was seen in HT patients (P < 0.02). CONCLUSION The data suggest that TPOAb do not differ only in quantity between HT patients and healthy individuals, but may also follow distinct qualitative patterns. Larger studies are required to confirm this, and to determine whether the propensity to produce antibodies to certain TPO epitopes, for example, IDR-A, is of pathogenic relevance.
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Affiliation(s)
- Claus H Nielsen
- Department of Clinical Immunology, Section 7631, Rigshospitalet University Hospital, Copenhagen, Denmark.
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Onda M, Beers R, Xiang L, Nagata S, Wang QC, Pastan I. An immunotoxin with greatly reduced immunogenicity by identification and removal of B cell epitopes. Proc Natl Acad Sci U S A 2008; 105:11311-6. [PMID: 18678888 PMCID: PMC2516223 DOI: 10.1073/pnas.0804851105] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Indexed: 11/18/2022] Open
Abstract
Recombinant immunotoxins are hybrid proteins composed of an Fv that binds to a tumor antigen fused to a bacterial or plant toxin. Immunotoxin BL22 targets CD22 positive malignancies and is composed of an anti-CD22 Fv fused to a 38-kDa fragment of Pseudomonas exotoxin A (PE38). BL22 has produced many complete remissions in drug-resistant Hairy cell leukemia, where many treatment cycles can be given, because neutralizing antibodies do not form. In marked contrast, only minor responses have been observed in trials with immunotoxins targeting solid tumors, because only a single treatment cycle can be given before antibodies develop. To allow more treatment cycles and increase efficacy, we have produced a less immunogenic immunotoxin by identifying and eliminating most of the B cell epitopes on PE38. This was accomplished by mutation of specific large hydrophilic amino acids (Arg, Gln, Glu, Lys) to Ala, Ser, or Gly. The new immunotoxin (HA22-8X) is significantly less immunogenic in three strains of mice, yet retains full cytotoxic and anti-tumor activities. Elimination of B-cell epitopes is a promising approach to the production of less immunogenic proteins for therapeutic purposes.
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Affiliation(s)
- Masanori Onda
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4264
| | - Richard Beers
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4264
| | - Laiman Xiang
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4264
| | - Satoshi Nagata
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4264
| | - Qing-cheng Wang
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4264
| | - Ira Pastan
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4264
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Deladoëy J, Pfarr N, Vuissoz JM, Parma J, Vassart G, Biesterfeld S, Pohlenz J, Van Vliet G. Pseudodominant inheritance of goitrous congenital hypothyroidism caused by TPO mutations: molecular and in silico studies. J Clin Endocrinol Metab 2008; 93:627-33. [PMID: 18029453 DOI: 10.1210/jc.2007-2276] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT AND OBJECTIVE Most cases of goitrous congenital hypothyroidism (CH) from thyroid dyshormonogenesis 1) follow a recessive mode of inheritance and 2) are due to mutations in the thyroid peroxidase gene (TPO). We report the genetic mechanism underlying the apparently dominant inheritance of goitrous CH in a nonconsanguineous family of French Canadian origin. DESIGN, SETTING, AND PARTICIPANTS Two brothers identified by newborn TSH screening had severe hypothyroidism and a goiter with increased (99m)Tc uptake. The mother was euthyroid, but the father and two paternal uncles had also been diagnosed with goitrous CH. After having excluded PAX8 gene mutations, we hypothesized that the underlying defect could be TPO mutations. RESULTS Both compound heterozygous siblings had inherited a mutant TPO allele carried by their mother (c.1496delC; p.Pro499Argfs2X), and from their father, one brother had inherited a missense mutation (c.1978C-->G; p.Gln660Glu) and the other an insertion (c.1955insT; p.Phe653Valfs15X). The thyroid gland of one uncle who is a compound heterozygote for TPO mutations (p.Phe653Valfs15X/p.Gln660Glu) was removed because of concurrent multiple endocrine neoplasia type 2A. Immunohistochemistry revealed normal TPO staining, implying that Gln660Glu TPO is expressed properly. Modeling of this mutant in silico suggests that its three-dimensional structure is conserved, whereas the electrostatic binding energy between the Gln660Glu TPO and its heme group becomes repulsive. CONCLUSION We report a pedigree presenting with pseudodominant goitrous CH due to segregation of three different TPO mutations. Although goitrous CH generally follows a recessive mode of inheritance, the high frequency of TPO mutations carriers may lead to pseudodominant inheritance.
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Affiliation(s)
- Johnny Deladoëy
- Endocrinology Service and Research Center, Sainte-Justine Hospital and Department of Pediatrics, University of Montreal, Montreal, Canada H3T 1C5
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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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Hilpert K, Winkler DFH, Hancock REW. Cellulose-bound Peptide Arrays: Preparation and Applications. Biotechnol Genet Eng Rev 2007; 24:31-106. [DOI: 10.1080/02648725.2007.10648093] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Onda M, Nagata S, FitzGerald DJ, Beers R, Fisher RJ, Vincent JJ, Lee B, Nakamura M, Hwang J, Kreitman RJ, Hassan R, Pastan I. Characterization of the B cell epitopes associated with a truncated form of Pseudomonas exotoxin (PE38) used to make immunotoxins for the treatment of cancer patients. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2006; 177:8822-34. [PMID: 17142785 DOI: 10.4049/jimmunol.177.12.8822] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recombinant immunotoxins composed of an Ab Fv fragment joined to a truncated portion of Pseudomonas exotoxin A (termed PE38) have been evaluated in clinical trials for the treatment of various human cancers. Immunotoxin therapy is very effective in hairy cell leukemia and also has activity in other hemological malignancies; however, a neutralizing Ab response to PE38 in patients with solid tumors prevents repeated treatments to maximize the benefit. In this study, we analyze the murine Ab response as a model to study the B cell epitopes associated with PE38. Sixty distinct mAbs to PE38 were characterized. Mutual competitive binding of the mAbs indicated the presence of 7 major epitope groups and 13 subgroups. The competition pattern indicated that the epitopes are discrete and could not be reproduced using a computer simulation program that created epitopes out of random surface residues on PE38. Using sera from immunotoxin-treated patients, the formation of human Abs to each of the topographical epitopes was demonstrated. One epitope subgroup, E1a, was identified as the principal neutralizing epitope. The location of each epitope on PE38 was determined by preparing 41 mutants of PE38 in which bulky surface residues were mutated to either alanine or glycine. All 7 major epitope groups and 9 of 13 epitope subgroups were identified by 14 different mutants and these retained high cytotoxic activity. Our results indicate that a relatively small number of discrete immunogenic sites are associated with PE38, most of which can be eliminated by point mutations.
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Affiliation(s)
- Masanori Onda
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Drive, Bethesda, MD 20892, USA
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Rebuffat SA, Bresson D, Nguyen B, Péraldi-Roux S. The key residues in the immunodominant region 353–363 of human thyroid peroxidase were identified. Int Immunol 2006; 18:1091-9. [PMID: 16735377 DOI: 10.1093/intimm/dxl042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Auto-antibodies (aAbs) to thyroid peroxidase (TPO) interact with a restricted immunodominant region (IDR) divided into two overlapping regions A and B. Among the five major regions structuring the IDR/B, regions 210-225, 353-363, 549-563, 713-720 and 766-775, region 353-363 constitutes an important anchor point for the binding of TPO-specific aAbs in sera from Hashimoto's and Graves' patients. We combined site-directed mutagenesis and expression of TPO mutants in stably transfected CHO cells to precisely define the critical residues in that region. By using flow cytometry and ELISA, we identified four amino acid residues, H353, D358, S359 and R361, that contribute to the interaction between human TPO and anti-TPO aAbs. This identification of these contributing amino acid residues in the IDR allowed us to more precisely depict contours of the IDR.
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Affiliation(s)
- Sandra A Rebuffat
- CNRS UMR 5160, Faculté de Pharmacie, 34093 Montpellier Cedex 5, France
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Benvenga S, Santarpia L, Trimarchi F, Guarneri F. Human thyroid autoantigens and proteins of Yersinia and Borrelia share amino acid sequence homology that includes binding motifs to HLA-DR molecules and T-cell receptor. Thyroid 2006; 16:225-36. [PMID: 16571084 DOI: 10.1089/thy.2006.16.225] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We previously reported that the spirochete Borrelia burgdorferi could trigger autoimmune thyroid diseases (AITD). Subsequently, we showed local amino acid sequence homology between all human thyroid autoantigens (human thyrotropin receptor [hTSH-R], human thyroglobulin [hTg], human thyroperoxidase [hTPO], human sodium iodide symporter [hNIS]) and Borrelia proteins (n = 6,606), and between hTSH-R and Yersinia enterocolitica (n = 1,153). We have now updated our search of homology with Borrelia (n = 11,198 proteins) and extended our search on Yersinia to the entire species (n = 40,964 proteins). We also searched the homologous human and microbial sequences for peptide-binding motifs of HLA-DR molecules, because a number of these class II major histocompatibility complex (MHC) molecules (DR3, DR4, DR5, DR8, and DR9) are associated with AITD. Significant homologies were found for only 16 Borrelia proteins (5 with hTSH-R, 2 with hTg, 3 with hTPO, and 6 with hNIS) and only 19 Yersinia proteins (4 with hTSH-R, 2 with hTg, 2 with hTPO, and 11 with hNIS). Noteworthy, segments of thyroid autoantigens homologous to these microbial proteins are known to be autoantigenic. Also, the hTSH-R homologous region of one Borrelia protein (OspA) contains an immunodominant epitope that others have found to be homologous to hLFA-1. This is of interest, as the hLFA-1/ICAM-1 ligand/receptor pair is aberrantly expressed in the follicular cells of thyroids affected by Hashimoto's thyroiditis. A computer-assisted search detected antigenic peptide binding motifs to the DR molecules implicated in AITD. In conclusion, our in silico data do not directly demonstrate that Borrelia and Yersinia proteins trigger AITD but suggest that a restricted number of them might have the potential to, at least in persons with certain HLA-DR alleles.
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Affiliation(s)
- Salvatore Benvenga
- Sezione di Endocrinologia del Dipartimento Clinico Sperimentale di Medicina e Farmacologia, Università di Messina, Messina, Italy.
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16
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Nydegger UE, Tevaearai H, Berdat P, Rieben R, Carrel T, Mohacsi P, Flegel WA. Histo-blood group antigens as allo- and autoantigens. Ann N Y Acad Sci 2005; 1050:40-51. [PMID: 16014519 DOI: 10.1196/annals.1313.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The science of blood groups has made giant steps forward during the last decade. Blood-group typing of red blood cells (RBCs) is performed on more than 15 million samples per year in Europe, today much less often for forensic reasons than for clinical purposes such as transfusion and organ transplantation. Specific monoclonal antibodies are used with interpretation on the basis of RBC agglutination patterns, and mass genotyping may well be on its way to becoming a routine procedure. The discovery that most blood group systems, whose antigens are by definition found on RBCs, are also expressed in multiple other tissues has sparked the interest of transplantation medicine in immunohematology beyond the HLA system. The one and only "histo-blood group" (HBG) system that is routinely considered in transplantation medicine is ABO, because ABO antigen-incompatible donor/recipient constellations are preferably avoided. However, other HBG systems may also play a role, thus far underestimated. This paper is an up-to-date analysis of the importance of HBG systems in the alloimmunity of transplantation and autoimmune events, such as hemolytic anemia.
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Affiliation(s)
- Urs E Nydegger
- Clinic for Cardiovascular Surgery, Inselspital, CH-3010 Bern, Switzerland.
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17
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Ruf J, Carayon P. Structural and functional aspects of thyroid peroxidase. Arch Biochem Biophys 2005; 445:269-77. [PMID: 16098474 DOI: 10.1016/j.abb.2005.06.023] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2005] [Revised: 06/16/2005] [Accepted: 06/20/2005] [Indexed: 10/25/2022]
Abstract
Thyroperoxidase (TPO) is the enzyme involved in thyroid hormone synthesis. Although many studies have been carried out on TPO since it was first identified as being the thyroid microsomal antigen involved in autoimmune thyroid disease, previous authors have focused more on the immunological than on the biochemical aspects of TPO during the last few years. Here, we review the latest contributions in the field of TPO research and provide a large reference list of original publications. Given this promising background, scientists and clinicians will certainly continue in the future to investigate the mechanisms whereby TPO contributes to hormone synthesis and constitutes an important autoantigen involved in autoimmune thyroid disease, and the circumstances under which the normal physiological function of this enzyme takes on a pathological role.
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Affiliation(s)
- Jean Ruf
- INSERM Unit U555, Faculté de Médecine Timone, Université de la Méditerranée, Marseille, France.
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18
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Bresson D, Rebuffat SA, Nguyen B, Banga JP, Gardas A, Peraldi-Roux S. New insights into the conformational dominant epitopes on thyroid peroxidase recognized by human autoantibodies. Endocrinology 2005; 146:2834-44. [PMID: 15761037 DOI: 10.1210/en.2005-0038] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Human anti-thyroperoxidase (TPO) autoantibodies (aAbs) are a major hallmark of autoimmune thyroid diseases. Their epitopes are discontinuous and mainly restricted to an immunodominant region (IDR) consisting of two overlapping regions (IDR/A and B). To shed light on the relationship between these regions, we first performed competitive studies using all available reference anti-TPO antibodies. Interestingly, we showed that human IDR/A- and B-specific anti-TPO aAbs recognized essentially the same regions on the TPO molecule. However, our data also indicated that IDR/A-specific human aAbs strongly recognized the region containing residues 599-617, whereas the IDR/B-specific aAbs bind to several regions as well as region 599-617. Next, we scanned this key region to identify the residues involved in the immunodominant autoepitope. Using peptide spot technology together with competitive ELISA experiments, we demonstrated that residues (604)ETP-DL(609) play a major role in the anti-peptide P14 epitope and that IDR/A-specific human anti-TPO aAbs, either expressed as recombinant Fab or obtained from Graves' disease patients, specifically recognize the sequences (597)FCGLPRLE(604) and (611)TAIASRSV(618). All together our data emphasize that both the IDRs involve the same surface area on human TPO, but the differential usage of one or the other regions leads to different inhibition patterns in competitive experiments. In conclusion, our data help to resolve the long-sought issue on the molecular immunology of the two IDRs on TPO and provide new clues to design efficient peptides that may be part of a combinatorial treatment aiming at delaying development of autoimmune thyroiditis when used prophylactically.
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Affiliation(s)
- Damien Bresson
- Centre National de la Recherche Scientifique UMR 5160, Centre de Pharmacologie et Biotechnologie pour la Santé, 15 avenue Charles Flahault, BP 14491, 34093 Montpellier, Cedex 5, France
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19
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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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Abstract
Thyroid peroxidase (TPO) is a key enzyme in the formation of thyroid hormones and a major autoantigen in autoimmune thyroid diseases. Titers of TPO antibodies also correlate with the degree of lymphocytic infiltration in euthyroid subjects, and they are frequently present in euthyroid subjects (prevalence 12-26%). Even within the normal range for thyrotropin (TSH), TPO antibody titers correlate with TSH levels, suggesting that their presence heralds impending thyroid failure. Assays for serum TPO antibodies have become much more sensitive, and very low titers can be found in virtually all subjects. However, titers above an assay-dependent cut-off are a clear risk factor for hypothyroidism; in the Whickham survey the annual risk of developing hypothyroidism in TPO-positive women with normal thyrotropin levels was 2.1%. Measuring TPO antibodies in euthyroid subjects can be used to identify subjects with increased risk for hypothyroidism: e.g. as triage to measure thyrotropin. This could be done in women who wish to become pregnant and those with an increased risk per se who are pregnant (to predict first trimester hypothyroidism, and postpartum thyroid dysfunction), patients with other autoimmune diseases, subjects on amiodarone, lithium, or interferon-alpha, and in relatives of patients with autoimmune thyroid diseases.
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Affiliation(s)
- Mark F Prummel
- Department of Endocrinology and Metabolism, F5-169 Academic Medical Center, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands.
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Abstract
The year 2004 represents a milestone for the biosensor research community: in this year, over 1000 articles were published describing experiments performed using commercially available systems. The 1038 papers we found represent an approximately 10% increase over the past year and demonstrate that the implementation of biosensors continues to expand at a healthy pace. We evaluated the data presented in each paper and compiled a 'top 10' list. These 10 articles, which we recommend every biosensor user reads, describe well-performed kinetic, equilibrium and qualitative/screening studies, provide comparisons between binding parameters obtained from different biosensor users, as well as from biosensor- and solution-based interaction analyses, and summarize the cutting-edge applications of the technology. We also re-iterate some of the experimental pitfalls that lead to sub-optimal data and over-interpreted results. We are hopeful that the biosensor community, by applying the hints we outline, will obtain data on a par with that presented in the 10 spotlighted articles. This will ensure that the scientific community at large can be confident in the data we report from optical biosensors.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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Pendergraft WF, Pressler BM, Jennette JC, Falk RJ, Preston GA. Autoantigen complementarity: a new theory implicating complementary proteins as initiators of autoimmune disease. J Mol Med (Berl) 2004; 83:12-25. [PMID: 15592920 DOI: 10.1007/s00109-004-0615-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2004] [Accepted: 10/18/2004] [Indexed: 11/29/2022]
Abstract
Autoimmune diseases affect approximately 1 in 21 persons in the United States. Treatment often requires long-term cytotoxic therapy. How and why these deleterious diseases occur is unclear. A serendipitous finding in our laboratory using serum from patients with autoimmune vasculitis led us to develop the theory of autoantigen complementarity, a novel concept that may elucidate the etiological and pathogenetic mechanisms underlying autoimmune disease in general. The theory proposes that the inciting immunogen that elicits a cascade of immunological events is not the self-antigen (the autoantigen) or its mimic but rather a protein that is complementary in surface structure to the autoantigen; that is, a protein homologous or identical to the amino acid sequence of translated antisense RNA from the noncoding strand of the autoantigen gene. The cascade begins when this complementary protein initiates the production of antibodies that in turn elicit an anti-antibody or anti-idiotypic response. These anti-idiotypic antibodies can now react with the autoantigen. Strikingly, homology search of complementary proteins yields microbial and fungal proteins, thus indicating that invading micro-organisms can deliver the inciting immunogen. Curiously, approximately 50% of our patients transcribe the complementary protein's antisense RNA. If it transpires that these aberrant RNAs are translated, the complementary protein would be produced by the individual. Here we review published research investigating complementary proteins, anti-idiotypic immune responses, and antisense transcripts, all of which support complementary proteins as initiators of autoimmune disease. In addition, we provide possible microbial and/or fungal organisms that may incite some of the most studied autoimmune diseases. Lastly, we propose mechanisms by which cell-mediated autoimmunity can be triggered by autoantigen complementarity. Based on our data and the contributions of the researchers described in this review, identification of proteins complementary to autoantigens is likely to be informative in most autoimmune diseases. This vein of study is in the early phases; however, we expect "autoantigen complementarity" is an underlying mechanism in many autoimmune diseases.
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Affiliation(s)
- William F Pendergraft
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7155, USA
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