Human monoclonal thyroglobulin autoantibodies: epitopes and immunoglobulin genes.
01 Oct 2004-The Journal of Clinical Endocrinology and Metabolism (Endocrine Society)-Vol. 89, Iss: 10, pp 5116-5123
TL;DR: The TgAb panel provides novel information regarding the repertoire of H chain genes encoding human TgAbs as well as the relationship between the H chains and the epitopes recognized on this major thyroid autoantigen.
Abstract: Autoantibodies to thyroglobulin (TgAbs) are common markers of thyroid autoimmunity, but relatively few human monoclonal TgAbs have been described. From a panel of 64 human monoclonal TgAbs (isolated from a thyroid-disease derived combinatorial Ig gene library), we selected seven with unique genetic features for detailed characterization. These TgAbs preferentially recognize native (not denatured) Tg, like serum autoantibodies. Most have high affinities for Tg (dissociation constant 10(-10) to 10(-9) m). Their light (L) chain Ig genes are not unusual, but four of the five heavy (H) chain genes are new. Moreover, one H chain belongs to the small VH2 family, not previously reported for autoantibodies to Tg or thyroid peroxidase. The TgAbs inhibit the binding to Tg of the thyroid donor's serum autoantibodies, indicating epitopic overlap. Competition analysis (surface plasmon resonance) shows that the TgAbs recognize overlapping epitopes in an immunodominant region on the Tg dimer ( approximately 660 kDa). Two major and several minor epitopic regions were defined, each associated with a particular H + L chain combination. In conclusion, our TgAb panel provides novel information regarding the repertoire of H chain genes encoding human TgAbs as well as the relationship between the H chains and the epitopes recognized on this major thyroid autoantigen.
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Abstract: In the year 2003 there was a 17% increase in the number of publications citing work performed using optical biosensor technology compared with the previous year. We collated the 962 total papers for 2003, identified the geographical regions where the work was performed, highlighted the instrument types on which it was carried out, and segregated the papers by biological system. In this overview, we spotlight 13 papers that should be on everyone's 'must read' list for 2003 and provide examples of how to identify and interpret high-quality biosensor data. Although we still find that the literature is replete with poorly performed experiments, over-interpreted results and a general lack of understanding of data analysis, we are optimistic that these shortcomings will be addressed as biosensor technology continues to mature.
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...[111–289], antibody–antigen [290–411] and receptor–...
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...research performed using Biacore instruments [111–931]....
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TL;DR: The goal of inducing self-tolerance to prevent autoimmune thyroid disease will require accurate prediction of at-risk individuals together with an antigen-specific, not blanket, therapeutic approach.
Abstract: Thyroid autoimmunity involves loss of tolerance to thyroid proteins in genetically susceptible individuals in association with environmental factors. In central tolerance, intrathymic autoantigen presentation deletes immature T cells with high affinity for autoantigen-derived peptides. Regulatory T cells provide an alternative mechanism to silence autoimmune T cells in the periphery. The TSH receptor (TSHR), thyroid peroxidase (TPO), and thyroglobulin (Tg) have unusual properties ("immunogenicity") that contribute to breaking tolerance, including size, abundance, membrane association, glycosylation, and polymorphisms. Insight into loss of tolerance to thyroid proteins comes from spontaneous and induced animal models: 1) intrathymic expression controls self-tolerance to the TSHR, not TPO or Tg; 2) regulatory T cells are not involved in TSHR self-tolerance and instead control the balance between Graves' disease and thyroiditis; 3) breaking TSHR tolerance involves contributions from major histocompatibility complex molecules (humans and induced mouse models), TSHR polymorphism(s) (humans), and alternative splicing (mice); 4) loss of tolerance to Tg before TPO indicates that greater Tg immunogenicity vs TPO dominates central tolerance expectations; 5) tolerance is induced by thyroid autoantigen administration before autoimmunity is established; 6) interferon-α therapy for hepatitis C infection enhances thyroid autoimmunity in patients with intact immunity; Graves' disease developing after T-cell depletion reflects reconstitution autoimmunity; and 7) most environmental factors (including excess iodine) "reveal," but do not induce, thyroid autoimmunity. Micro-organisms likely exert their effects via bystander stimulation. Finally, no single mechanism explains the loss of tolerance to thyroid proteins. The goal of inducing self-tolerance to prevent autoimmune thyroid disease will require accurate prediction of at-risk individuals together with an antigen-specific, not blanket, therapeutic approach.
160 citations
TL;DR: The pattern of Tg recognition is similar when HT patients are compared to GD and NTMG to PTC patients and differs when AITD are compared with non-AITD patients.
Abstract: Context: Thyroglobulin (Tg) epitopes of serum Tg autoantibodies (TgAb) have been characterized using inhibition of Tg binding by human monoclonal TgAb in autoimmune thyroid diseases (AITD) [Hashimoto’s thyroiditis (HT) and Graves’ disease (GD)] but not in non-AITD [nontoxic multinodular goiter (NTMG) and papillary thyroid carcinoma (PTC)]. Objective: Our objective was to compare Tg epitopes of serum TgAb from patients with AITD, non-AITD, and PTC associated with histological thyroiditis (PTC-T) using inhibition of Tg binding by four recombinant human TgAb-Fab (epitopic regions A–D). Design: Inhibition of Tg binding of 24 HT, 25 GD, 19 NTMG, 15 PTC, and 25 PTC-T TgAb-positive sera by each TgAb-Fab was evaluated in ELISA. Inhibition by the pool of the four TgAb-Fab was evaluated using labeled Tg. Results: Levels of inhibition were different for TgAb-Fab regions A (P = 0.001), B (0.007), and D (0.011). Inhibition by region A TgAb-Fab was significantly higher in HT, GD, and PTC-T than in NTMG and PTC patients...
71 citations
TL;DR: Iodine-induced thyroid autoimmunity is related to TgAb and the unmasking of a cryptic epitope on Tg contributes to this relationship in humans.
Abstract: Context: The mechanisms linking thyroid autoimmunity and iodine use in humans are unknown. Objective: Our aim was to correlate iodine intake, thyroid autoimmunity, and recognition of thyroglobulin (Tg) epitopes after implementation of iodine prophylaxis. Setting: The general community living in an Italian village was evaluated. Main Outcome Measures: Thyroglobulin autoantibodies (TgAb), thyroperoxidase autoantibodies (TPOAb), and urinary iodine excretion were assessed in 906 iodized salt users (IS-users) and 389 nonusers (IS-nonusers). Ultrasound (US) was performed to identify thyroid hypoechogenicity, suggestive of Hashimoto thyroiditis (HT). TgAb epitope pattern in 16 IS-users and 17 IS-nonusers was evaluated by an inhibition binding assay to Tg, using human monoclonal TgAb-Fab directed to A, B, C, and D epitopes on Tg. Results: Median urinary iodine excretion was slightly higher in IS-users than in IS-nonusers (112.0 μg/L vs 86.5 μg/L; P < .01). TgAb, and not TPOAb, was more frequent in IS-users (18.9%...
67 citations
TL;DR: In papillary thyroid carcinoma, LT on histology must be carefully searched for because it is frequently associated with TgAb and therefore mistakenly low or undetectable Tg, which can be underestimated in patients with T g autoantibodies (TgAb).
Abstract: Context: Serum thyroglobulin (Tg), the marker of residual tumor in papillary thyroid carcinoma, can be underestimated in patients with Tg autoantibodies (TgAb) TgAb are due to a coexistent lymphocytic thyroiditis (LT) or the papillary thyroid carcinoma per se TgAb assays are highly discordant Design: We evaluated 141 patients with a clinical diagnosis of nodular thyroid disease, 32 of Hashimoto's thyroiditis, and four of Graves' disease, who underwent total thyroidectomy for an associated papillary thyroid carcinoma Patients were classified as papillary thyroid carcinoma-lymphocytic thyroiditis (PTC-T) and papillary thyroid carcinoma (PTC) according to the presence or absence of LT on histology Tg was measured before thyroid remnant ablation, when it is expectedly detectable, by an immunometric assay (IMA) and TgAb by three noncompetitive IMA and three competitive radioimmunoassays (RIA) The number of lymphocytes was compared with TgAb concentration Results: Seventy-two of 177 patients (407%) were
59 citations
References
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Journal Article•
17 citations
TL;DR: In this article, a human Thyroglobulin autantibody was cloned and expressed using a human autoencoder, and the expression was performed on a human.
Abstract: (1991). Cloning and Expression of a Human Thyroglobulin Autoantibody. Autoimmunity: Vol. 11, No. 1, pp. 69-70.
14 citations
TL;DR: It is demonstrated that the diversity of the L chain library repertoire, while having little effect on immunological properties, has a major influence on the genes encoding antigen-specific Fab selected from a combinatorial library.
Abstract: The diversity of the immunoglobulin heavy (H) and light (L) gene libraries used to construct a combinatorial library is an important parameter in determining the characteristics of antigen-specific Fab obtained from the library. To investigate the role of library diversity, we compared Fab specific for the autoantigen thyroid peroxidase (TPO) isolated from two different combinatorial libraries. Both libraries contained the same H chain genes. The original combinatorial library (H/R) utilized kappa chains generated using a single kappa variable region oligonucleotide primer. We constructed a second combinatorial library (H/D) containing kappa chains amplified with a diverse panel of variable region primers. From the the original H/R library, only two groups of TPO-specific Fab had been obtained, involving two H chain types (V1-3B and hvlL1) but only one kappa chain type (012). In contrast, among the seven TPO Fab characterized from the second library (H/D) we observed five different VH/VL combinations, com...
12 citations
TL;DR: The authors' data indicate that the promiscuous primer preferentially amplifies the dominant L chain present in vivo, and provides insight into the relationship between TPO autoantibody gene usage, epitopic recognition, and the effectiveness of the combinatorial library approach.
12 citations
TL;DR: Insight is provided into the difficulties involved in the identification of the TSH receptor with serum containing TSI and no specific immunoprecipitation of any protein was observed when radiolabeled guinea pig membrane proteins were used.
Abstract: Characterization of the antigen to thyroid-stimulating immunoglobulin (TSI), presumably the TSH receptor, remains elusive. We, therefore, attempted immunoprecipitation of the TSI antigen using cultured human thyroid cells radiolabeled to high specific activity by [35S]methionine (all proteins labeled) or by 125I and lactoperoxidase (primarily cell surface proteins labeled). Both techniques produced similar results. Crude membrane preparations from the labeled cells were solubilized in buffer containing 1% Triton and then incubated with TSI-containing or control serum. Immunoglobulin was precipitated with goat antihuman immunoglobulin and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. About 30 proteins were immunoprecipitated by both normal and control sera. However, only 1 protein (mol wt, ∼320,000) was preferentially selected by TSI-containing serum (6 of 6 tested). This protein was also immunoprecipitated by the majority of sera from patients with Hashimoto’s...
12 citations