A Flexible Mouse Model of Autoimmune Thyroiditis Induced by Immunization with an Adenovirus Containing Full-Length Thyroglobulin cDNA.

The main challenge in the "post-GWAS" era is to determine the functional meaning of genetic variants and their contribution to disease pathogenesis. Development of suitable mouse models is critical because disease susceptibility is triggered by complex interactions between genetic, epigenetic, and environmental factors that cannot be modeled by in vitro models. Thyroglobulin (TG) is a key gene for autoimmune thyroid disease (AITD) and several single nucleotide polymorphisms (SNPs) in the TG coding region have been associated with AITD. The classical model of experimental autoimmune thyroiditis (EAT), based on immunization of genetically susceptible mouse strains with purified TG protein in adjuvant, does not allow testing the impact of TG sequence variants on the development of autoimmune thyroiditis. Here we describe a protocol for the induction of EAT by immunization of mice susceptible to thyroiditis with an adenovirus vector carrying full-length human TG cDNA (Ad-TG EAT). We also provide support protocols for evaluation of autoimmune thyroiditis including serological assessment of TG antibodies, in vitro splenocyte proliferation assay and cytokines secretion, thyroid histology, and evaluation of thyroid lymphocytic infiltration by immunostaining. This protocol for EAT induction allows manipulation of the TG cDNA to introduce variants associated with AITD, enabling the testing of the functional effects of susceptible variants and their haplotypes on the immunogenicity of TG. Furthermore, the Ad-TG EAT mouse model is a valuable model for studying the interactions of the TG variants with non-genetic factors influencing AITD development (e.g., cytokines, iodine exposure) or with variants of other susceptible genes (e.g., HLA-DRß1). © 2024 Wiley Periodicals LLC. Basic Protocol: Development of a mouse model of autoimmune thyroiditis induced by immunization with adenovirus containing full-length thyroglobulin cDNA Support Protocol 1: Splenocytes isolation Support Protocol 2: T cell stimulation and carboxyfluorescein diacetate succinimidyl ester (CFSE) based cell proliferation assay Support Protocol 3: Cytokine assays: measuring levels of interferon gamma (IFNγ) and interleukins IL-2, IL-4, and IL-10 in splenocyte supernatants Support Protocol 4: Evaluating thyroid histology and infiltration with immune cells: hematoxylin-eosin staining of mice thyroid glands Support Protocol 5: Immunohistochemistry of thyroid tissues: Immunofluorescence protocol of paraffin-embedded thyroid sections Support Protocol 6: Anti-thyroglobulin antibody measurement in mice sera by enzyme-linked immunosorbent assay (ELISA).

The association between endothelial function and autoimmune thyroiditis induced by iodine excess.

BACKGROUND: Iodine excess (IE) intake leads to lymphocyte dysfunction and contributes to autoimmune thyroiditis (AIT). Abnormal thyroid function is associated with adverse cardiovascular events, endothelial dysfunction is often an early pathophysiological feature in most cardiovascular disease. However, the relationship between iodine and the cardiovascular system is currently unclear. Therefore, the aim of this study was to investigate the effects of IE on endothelial function in mouse model. METHODS: A total of 24 NOD.H-2h4 mice were randomly divided into different groups. A sodium iodide (NaI) group supplied with 0.05% NaI water for 8 weeks. Serum levels of tumor necrosis factors α (TNFα), interleukin-6 (IL-6) and C-reactive Protein (CRP), as well as endothelin-1 (ET-1), von Willebrand factor (VWF) and thrombomodulin (THBD) were detected by Elisa. In addition, the mRNA and protein expression of these genes were measured by RT-PCR and Western blotting. RESULTS: Here, we found the urinary iodine concentration (UIC) was higher in the NaI group compared to the control group. Serum levels of ET-1, VWF, and THBD were also significantly lower in the NaI group, however, CRP serum levels are significantly increased. In aorta, the mRNA and protein expression of ET-1, VWF, THBD were downregulated, however, the expression of IL-6, CRP and TNFα mRNA and protein were upregulated in the NaI group. A correlation analysis showed negative correlation between UIC with ET-1, VWF, and THBD, similarly, negative correlation between CRP with THBD was observed. In addition, positive correlations between UIC with CRP. CONCLUSION: Collectively, in the NOD.H-2h4 mice, IE supplementation had a suppressive effect on endothelial function, and this inhibition maybe due to the increase expression of inflammatory cytokines.

Generation of a Mouse Spontaneous Autoimmune Thyroiditis Model.

In recent years, Hashimoto's thyroiditis (HT) has become the most common autoimmune thyroid disease. It is characterized by lymphocyte infiltration and the detection of specific serum autoantibodies. Although the potential mechanism is still not clear, the risk of Hashimoto's thyroiditis is related to genetic and environmental factors. At present, there are several types of models of autoimmune thyroiditis, including experimental autoimmune thyroiditis (EAT) and spontaneous autoimmune thyroiditis (SAT). EAT in mice is a common model for HT, which is immunized with lipopolysaccharide (LPS) combined with thyroglobulin (Tg) or supplemented with complete Freund's adjuvant (CFA). The EAT mouse model is widely established in many types of mice. However, the disease progression is more likely associated with the Tg antibody response, which may vary in different experiments. SAT is also widely used in the study of HT in the NOD.H-2h4 mouse. The NOD.H2h4 mouse is a new strain obtained from the cross of the nonobese diabetic (NOD) mouse with the B10.A(4R), which is significantly induced for HT with or without feeding iodine. During the induction, the NOD.H-2h4 mouse has a high level of TgAb accompanied by lymphocyte infiltration in the thyroid follicular tissue. However, for this type of mouse model, there are few studies to comprehensively evaluate the pathological process during the induction of iodine. A SAT mouse model for HT research is established in this study, and the pathologic changing process is evaluated after a long period of iodine induction. Through this model, researchers can better understand the pathological development of HT and screen new treatment methods for HT.

A Mendelian randomization study of the effect of serum 25-hydroxyvitamin D levels on autoimmune thyroid disease.

Objective: The influence of vitamin D on autoimmune thyroid disease (AITD) remains a subject of ongoing debate. This study employs Mendelian randomization (MR) to investigate the causal correlations of serum 25-hydroxyvitamin D (25[OH]D) levels with autoimmune thyroiditis (AIT), autoimmune hyperthyroidism (AIH), and Graves disease (GD). Methods: Data on single nucleotide polymorphisms related to serum 25(OH)D levels, AIT, AIH, and GD were sourced from UK Biobank and FinnGen. Inverse variance weighted, MR-Egger, and weighted median were employed to test the exposure-outcome causal relationship. Assessments of horizontal pleiotropy, heterogeneity, and stability were performed using the MR-Egger intercept, Cochran's Q test, and leave-one-out sensitivity analysis, respectively. Results: The results of MR analysis showed increased serum 25(OH)D levels was associated with a reduced risk of AIT (OR 0.499, 95% CI 0.289 to 0.860, p = 0.012) but not causal associated with AIH (OR 0.935, 95% CI 0.695 to 1.256, p = 0.654) and GD (OR 0.813, 95% CI 0.635 to 1.040, p = 0.100). Intercept analysis showed no horizontal pleiotropy (p > 0.05), and Cochran's Q test showed no heterogeneity (p > 0.05). Sensitivity analysis suggested that these results were robust. Conclusion: An increased serum 25(OH)D level is associated with AIT risk reduction but unrelated to AIH and GD. This finding suggests that vitamin D supplementation can be valuable for preventing and treating AIT.

Effect of different iodine levels on the DNA methylation of PRKAA2, ITGA6, THEM4 and PRL genes in PI3K-AKT signaling pathway and population-based validation from autoimmune thyroiditis patients.

PURPOSE: Autoimmune thyroiditis (AIT) is one of the most common autoimmune endocrine diseases. The currently recognized causes are genetic susceptibility, environmental factors and immune disorders. It is important to clarify the pathogenesis for the prevention, diagnosis, treatment of AIT and scientific iodine supplementation. This study analyzed the DNA methylation levels of PRKAA2, ITGA6, PRL and THEM4 genes related to PI3K-AKT signaling pathway, compared the DNA methylation levels between cases and controls from different water iodine levels in Shandong Province of China, and evaluated the contribution of PI3K-AKT signaling pathway-related genes in AIT. METHODS: A total of 176 adult AIT patients were included from three different water iodine areas, and 176 healthy controls were included according to gender, age and BMI. According to the results of the Illumina Methylation 850 K BeadChip in our previous research, the significant methylation differences of genes on the PI3K-AKT signaling pathway related to AIT were determined. The MethylTarget™ assay was used to detect the methylation levels of the target genes, and real-time PCR experiments were used to verify the mRNA expression levels. RESULTS: Compared with the control group, PRKAA2_3 and 15 CpG sites were hyper-methylated. ITGA6 gene and 2 CpG sites were hypo-methylated in AIT cases. The mRNA expression of ITGA6 gene was negatively correlated with the DNA methylation levels of ITGA6 gene and 2 CpG sites. Compared with cases and controls in areas with different water iodine levels, methylation differences were mainly in PRKAA2 and ITGA6 genes. The methylation levels of PRKAA2_1 and PRKAA2_3 were positively correlated with age. The methylation levels of PRL and THEM4 genes were negatively correlated with age. The methylation level of PRKAA2_3 was positively correlated with FT4. CONCLUSION: In summary, we identified aberrant DNA methylation levels of PRKAA2 and ITGA6 genes related to PI3K-AKT signaling pathway in the blood of AIT patients. Both iodine supplementation after long-term iodine deficiency and iodine excess can affect the DNA methylation levels of PRKAA2 and ITGA6 genes, and the former affects more obviously. In ITGA6 gene, this aberrant epigenetic modification is associated with the increased mRNA expression.

Herb-partitioned moxibustion regulated the miRNA expression profile in the thyroid tissues of rats with experimental autoimmune thyroiditi.

OBJECTIVE: To observe the effect of herb-partitioned moxibustion (HPM) on the miRNA expression profile of thyroid tissue in experimental autoimmune thyroiditis (EAT) rats. METHODS: Rats were randomly divided into normal control (NC) group, EAT model (EAT) group, HPM group and western medicine (Med) group. EAT model rats were prepared by a combined immunization with complete and incomplete Freund's adjuvant emulsified with porcine thyroglobulin and iodine. Rats in the HPM group were treated with HPM, while rats in the Med group were treated with levothyrocine (1 µg/2 mL) by gavage. HE staining was used to observe the pathological morphological changes of thyroid tissue, ELISAs was uaed to detect the serum concentrations of TGAb, TPOAb, FT3, FT4, TSH. We then performed high-throughput miRNA sequencing to analyse the miRNA expression profiles in the thyroid tissues, followed by a bioinformatics analysis. RT-qPCR was used to verify the identified differentially expressed miRNAs. RESULTS: HPM improved the thyroid tissue morphology and reduced serum TPOAb, TGAb, TSH concentration in EAT rats (P < 0.05), but with no obvious effect on FT3 and FT4 concentration. While the TSH, FT3 and FT4 concentration was significantly changed in the Med group (P < 0.01 or P < 0.05) compared with that of EAT group. Sequencing results showed that a total of 17 miRNAs were upregulated, and 4 were downregulated in the EAT rats, in which the expression levels of miR-346 and miR-331-5p were reversed by HPM. The target genes of the miRNAs that regulated by HPM were associated with a variety of immune factors and immune signals. RT-qPCR verification showed that the expression of miRNA-346 and miRNA-331-5p was consistent with the sequencing results. CONCLUSIONS: HPM could regulate the the expression of miRNA-346 and miRNA-331-5p, then act on their target genes to immune and inflammation-related pathways, which may be one of the mechanisms of HPM on EAT rats.

Decreased Thyroid Peroxidase Antibody Titer in Response to Selenium Supplementation in Autoimmune Thyroiditis and the Influence of a Selenoprotein P Gene Polymorphism: A Prospective, Multicenter Study in China.

Background: Recent intervention studies have suggested that selenium (Se) is an effective treatment for autoimmune thyroiditis (AIT). However, the exact effect of Se on AIT is unclear as well as the mechanism of action. The aim of the present study was to explore the effect of Se on thyroid peroxidase antibody (TPOAb) titers in patients with AIT and to analyze the potential impact of the genetic background on the effect of Se supplementation. Methods: This was a randomized, placebo-controlled, double-blind trial. Three hundred and sixty-four patients with elevated TPOAb (>300 IU/mL) were recruited and randomized to receive Se yeast 200 µg/day supplementation or placebo. Urinary iodine concentration, serum thyrotropin, free thyroxine, TPOAb, Se, malondialdehyde, and serum glutathione peroxidase activity were measured at baseline and follow-up. Ninety-six patients were genotyped for single nucleotide polymorphism r25191G/A in the selenoprotein P (SEPP1/SELENOP) gene. Results: The median urinary iodine concentration was 182 µg/L. Serum Se increased significantly (p < 0.001) after Se treatment. TPOAb titer decreased by 10.0% at 3 months and by 10.7% at 6 months after Se supplementation, while there was a moderate increase in TPOAb titers over the follow-up period in patients receiving placebo. Glutathione peroxidase activity significantly increased (p < 0.001), and malondialdehyde significantly decreased (p < 0.001) after 6 months of Se supplementation. TPOAb titers decreased to variable extents in patients with different genotypes of single nucleotide polymorphism r25191G/A after Se supplementation. Serum TPOAb titers in patients with the AA genotype showed a more significant decrease (by 46.2%) than those with the GA and GG genotypes (by 14.5 and 9.8% respectively) at 3 months of Se supplementation (p = 0.070). Conclusions: Se supplementation significantly reduced TPOAb titers in patients with AIT, and there may be an important genetic component influencing interindividual differences in the decrease in TPOAb titers.

Iodine excess did not affect the global DNA methylation status and DNA methyltransferase expression in T and B lymphocytes from NOD.H-2h4 and Kunming mice.

Dysregulated DNA methylation in lymphocytes has been linked to various autoimmune disorders. Excessive iodine intake leads to lymphocyte dysfunction and contributes to autoimmune thyroiditis (AIT) flares in humans and animals. However, whether excessive iodine modifies the DNA methylation status in lymphocytes is unknown. Twenty NOD.H-2h4 mice and 20 Kunming mice were randomly divided into high iodine and control groups. We scored lymphatic infiltration in the thyroid by hematoxylin and eosin (H&E) staining and assayed serum thyroglobulin antibody (TgAb) levels by an indirect enzyme-linked immunosorbent assay. CD3+ T cells and CD19+ B cells were separated by flow cytometry. Global DNA methylation levels were examined by absorptiometry. Methylation of long interspersed nucleotide element-1 (LINE-1) repeats was detected with bisulfite sequencing PCR. Expression of DNA methyltransferase (DNMT) 1, DNMT3a and DNMT3b mRNA and protein were determined by real-time PCR and Western blot, respectively. We observed evident thyroiditis in the high­iodine-treated NOD.H-2h4 mice, while mice in the other three groups did not develop thyroiditis. No differences were found in the global methylation levels and methylation status of LINE-1 repeats in T and B lymphocytes from high­iodine-treated NOD.H-2h4 mice and Kunming mice compared with those from normal­iodine-supplemented controls. We did not find obvious changes in DNMT mRNA and protein expression levels in T and B lymphocytes among the studied groups. In conclusion, we showed for the first time that excess iodine did not affect the global methylation status or DNMT expression in T and B lymphocytes in NOD.H-2h4 and Kunming mice.

Modulation of T-Bet and GATA-3 expression in experimental autoimmune thyroiditis rats through ginsenoside treatment.

Hashimoto's thyroiditis (HT) is one of the most common organ-specific autoimmune diseases. Increasing evidence indicates that HT may be characterized by an imbalance in the helper T cell subsets Th1 and Th2. Traditional Chinese Medicine (TCM) considers HT as a chronic exhaustion disease, leading to deficiency of qi. In TCM, qi indicates the functional power of the organs of the human body; hence TCM recommends focusing the treatment of HT so as to increase qi production. Ginseng is a well-known herbal medicine exhibiting a variety of efficacies, its main function-being to generate qi. Ginseng's principal active component is ginsenoside, and modern pharmacology has shown that ginsenoside demonstrates biphasic immunomodulatory effects that can be utilized for the treatment of immune disorders. Previous work demonstrated that ginsenoside has a therapeutic effect on HT, but its mechanism is unknown. Experimental autoimmune thyroiditis rats were produced in order to investigate whether ginsenoside can modulate Th1/Th2 imbalance, the direct objective being to examine modulation of IFN-γ and IL-4 by ELISA, and the gene and protein expression of T-bet and GATA-3 by real-time PCR and Western blot. IFN-γ levels were increased while IL-4 levels decreased in EAT rats; treatment with ginsenoside led to decreased peripheral blood IFN-γ levels, with low doses statistically significant. Ginsenoside produced a biphasic effect on IL-4, with low and moderate doses promoting and high doses inhibiting secretion. Both protein and mRNA levels of T-bet were markedly reduced, while GATA-3 was significantly increased by ginsenoside.

A randomized-controlled, double-blind study of the impact of selenium supplementation on thyroid autoimmunity and inflammation with focus on the GPx1 genotypes.

PURPOSE: To analyze the impact of selenium supplementation on serum antiTPO levels and thyroid echogenicity in patients with CAT, evaluating the response in subgroups with different GPx1 genotypes. METHODS: CAT patients (n = 55) with positive antiTPO were randomized to selenomethionine (SeMet) 200 µg daily (n = 28) or placebo (n = 27) for 3 months. Assessments included GPx1 genotyping at baseline and serum levels of plasma selenium, erythrocyte GPx1 activity, antiTPO and thyroid echogenicity at baseline, and 3 and 6 months. RESULTS: In the SeMet group, the increase in plasma levels of selenium and erythrocyte GPx1 activity was similar among patients with different GPx1 genotypes. In the overall cohort, patients randomized to SeMet showed a 5 % decrease in antiTPO levels at 3 months (p = non-significant) and 20 % at 6 months (p < 0.001 versus 3 months). In contrast, patients in the placebo group did not show significant changes in antiTPO levels at any time point. Subgroup analysis showed that patients with different GPx1 genotypes presented comparable responses in antiTPO levels and echogenicity index to SeMet. CONCLUSIONS: Selenium supplementation decreased serum antiTPO levels in CAT patients, with similar response among patients with different GPx1 genotypes.

Environmental factors and thyroid autoimmunity.

Thyroid autoimmune disease, a multifactorial organ-specific autoimmune disorder, is marking a constant increase worldwide. It is thought to be caused by multiple environmental factors triggering autoimmune response in genetically susceptible individuals, though the exact mechanisms linking environmental factors to thyroid autoimmunity are not as yet well understood. Nevertheless, there is increasing evidence that mainly nutritive factors and environmental pollution by metals and chemicals (e.g. organochlorines, pesticides) are the main factors in the present-day spread of this disease. This review presents an overview of the current knowledge regarding environmental factors, their association with genetics and their impact on the immune system.

Vitamin D and autoimmune thyroid diseases.

The role of vitamin D as an immune modulator has been emphasized in recent years, and low levels of the hormone were observed in several autoimmune diseases including multiple sclerosis and systemic lupus erythematosus. Vitamin D mediates its effect though binding to vitamin D receptor (VDR), and activation of VDR-responsive genes. While VDR gene polymorphism was found to associate with autoimmune thyroid diseases (AITDs), few studies examined levels of vitamin D in these patients and those that did yielded conflicting results. We therefore undertook to evaluate the levels of vitamin D in patients with AITDs compared to patients with non-AITDs and healthy controls. Serum vitamin D (25-OH) levels were measured in 50 patients with AITDs, 42 patients with non-AITDs and 98 healthy subjects, utilizing the LIAISON chemiluminescence immunoassay (DiaSorin, Saluggia, Italy). Vitamin D deficiency was designated at levels lower than 10 ng/ml. Antithyroid antibodies, thyroid functions and demographic parameters were evaluated in all patients. The prevalence of vitamin D deficiency was significantly higher in patients with AITDs compared with healthy individuals (72% versus 30.6%; P<0.001), as well as in patients with Hashimoto's thyroiditis compared to patients with non-AITDs (79% versus 52%; P<0.05). Vitamin D deficiency also correlated to the presence of antithyroid antibodies (P=0.01) and abnormal thyroid function tests (P=0.059). Significantly low levels of vitamin D were documented in patients with AITDs that were related to the presence of anti thyroid antibodies and abnormal thyroid function tests, suggesting the involvement of vitamin D in the pathogenesis of AITDs and the advisability of supplementation.

Why is the thyroid so prone to autoimmune disease?

The thyroid gland plays a major role in the human body; it produces the hormones necessary for appropriate energy levels and an active life. These hormones have a critical impact on early brain development and somatic growth. At the same time, the thyroid is highly vulnerable to autoimmune thyroid diseases (AITDs). They arise due to the complex interplay of genetic, environmental, and endogenous factors, and the specific combination is required to initiate thyroid autoimmunity. When the thyroid cell becomes the target of autoimmunity, it interacts with the immune system and appears to affect disease progression. It can produce different growth factors, adhesion molecules, and a large array of cytokines. Preventable environmental factors, including high iodine intake, selenium deficiency, and pollutants such as tobacco smoke, as well as infectious diseases and certain drugs, have been implicated in the development of AITDs in genetically predisposed individuals. The susceptibility of the thyroid to AITDs may come from the complexity of hormonal synthesis, peculiar oligoelement requirements, and specific capabilities of the thyroid cell's defense system. An improved understanding of this interplay could yield novel treatment pathways, some of which might be as simple as identifying the need to avoid smoking or to control the intake of some nutrients.

Environmental factors and autoimmune thyroiditis.

Autoimmune thyroiditis, of which Hashimoto thyroiditis represents the most frequent form, is an inflammatory state of the thyroid gland that results from the interaction between genetic variants that promote susceptibility and environmental factors. High iodine intake, selenium deficiency, pollutants such as tobacco smoke, infectious diseases such as chronic hepatitis C, and certain drugs are implicated in the development of autoimmune thyroiditis, primarily in genetically predisposed people. Long-term iodine exposure leads to increased iodination of thyroglobulin, which increases its antigenicity and initiates the autoimmune process in genetically susceptible individuals. Selenium deficiency decreases the activity of selenoproteins, including glutathione peroxidases, which can lead to raised concentrations of hydrogen peroxide and thus promote inflammation and disease. Such environmental pollutants as smoke, polychlorinated biphenyls, solvents and metals have been implicated in the autoimmune process and inflammation. Environmental factors have not yet, however, been sufficiently investigated to clarify their roles in pathogenesis, and there is a need to assess their effects on development of the autoimmune process and the mechanisms of their interactions with susceptibility genes.

Autoimmune thyroid diseases.

PURPOSE OF REVIEW: Interesting clinical and basic studies have been published in the field of autoimmune thyroiditis (represented by Graves' disease and Hashimoto's thyroiditis) since January 2005. The review is organized into four main areas: genetics, environment, adaptive immune system, and innate immune system. RECENT FINDINGS: The quest continues for the identification of susceptibility genes for autoimmune thyroiditis. In addition to the classical major histocompatibility complex class II genes and cytotoxic T cell antigen-4, new studies have appeared on CD40 the protein tyrosine phosphatase-22. Too much iodine increases the incidence of Hashimoto's thyroiditis, perhaps by augmenting the antigenicity of thyroglobulin. T regulatory cells, Toll-like receptors and presentation of lipid antigens by CD1 molecules are new areas of basic immunological investigation that have been applied to autoimmune thyroiditis. SUMMARY: Overall, the studies have greatly expanded our understanding of the pathogenesis of thyroiditis. They have opened new lines of investigations that will ultimately result in a better clinical practice.

Iodine and IFN-gamma synergistically enhance intercellular adhesion molecule 1 expression on NOD.H2h4 mouse thyrocytes.

NOD.H2(h4) mice spontaneously develop autoimmune lymphocytic thyroiditis that mimics human Hashimoto's thyroiditis, a disease where iodine, IFN-gamma, and adhesion molecules have all been implicated in the pathogenesis. To study how iodine and IFN-gamma modulate the expression of ICAM-1, we analyzed NOD.H2(h4) thyrocytes in baseline conditions (day 0) and at several time points following supplementation of iodine in the drinking water. On day 0, a small percentage ( approximately 10%) of thyrocytes constitutively expressed ICAM-1. The expression gradually increased to 13, 25, and 41% on days 7, 14 and 28, respectively, returning to baseline (9%) on day 35. The initial ICAM-1 kinetics was paralleled by thyroidal infiltration of CD45(+) hemopoietic cells, which increased from an average of 4% on day 0 to an average of 13, 21, and 24% on days 14, 28, and 35, respectively. To distinguish whether the observed ICAM-1 increase was a direct effect of iodine or a consequence of the immune infiltrate, we treated mouse primary thyrocyte cultures with 0.01 mM sodium iodine and showed a 3-fold increased ICAM-1 expression. To assess interaction between IFN-gamma and iodine, we analyzed CD45 and ICAM-1expression on thyrocytes from NOD.H2(h4) wild-type and NOD.H2(h4) thyr-IFN-gamma transgenic littermates. Strikingly, IFN-gamma interacted synergistically with iodine to enhance ICAM-1 expression on thyrocytes. These findings suggest that iodine and IFN-gamma cooperate to promote thyroidal expression of ICAM-1 in this mouse model of thyroiditis, highlighting the complex interplay present in the pathogenesis of Hashimoto's thyroiditis.

Animal models for autoimmune myocarditis and autoimmune thyroiditis.

This chapter describes four murine models of autoimmune diseases: two related to autoimmune myocarditis and two related to autoimmune thyroiditis. The first model, Coxsackie virus B3 (CB3)-induced myocarditis, results in the development of acute myocarditis in susceptible as well as resistant mouse strains, whereas chronic myocarditis develops only in genetically susceptible mice. CB3-induced myocarditis closely resembles the course of human myocarditis, which is believed to be initiated by viral infection. Mouse cardiac myosin heavy chain has been identified as the major antigen associated with the late chronic phase of viral myocarditis. The second model is cardiac myosin-induced experimental autoimmune myocarditis (EAM) and, in a modification, cardiac alpha-myosin heavy chain peptide-induced myocarditis. In the EAM model, cardiac myosin or the relevant peptide in Freund's complete adjuvant (FCA) is injected subcutaneously into mice. The immune response, the histological changes, and the genetic susceptibility seen in EAM are similar to those of CB3-induced myocarditis. The third model is experimental autoimmune thyroiditis (EAT). EAT can be induced in genetically susceptible strains of mice by immunization with mouse thyroglobulin in FCA or lipopolysaccharide. Mice susceptible to EAT have the H-2A(k), H-2A(s), or H-2A(q) alleles. We describe here a standard technique for the induction of EAT; it was developed in our laboratory and is widely used as a model for studying Hashimoto's thyroiditis. The fourth model presented in this chapter is that of spontaneous autoimmune thyroiditis in NOD.H2h4 mice. These mice express the H-2A(k) allele on an NOD genetic background and develop spontaneous thyroiditis, which is exacerbated with dietary iodine.