Dog Thyroglobulin Research Articles

Evaluation of antithyroglobulin antibodies after routine vaccination in pet and research dogs.

To determine whether routine vaccination induces antibodies against bovine thyroglobulin and autoantibodies against canine thyroglobulin in dogs. Prospective study. 20 healthy research Beagles and 16 healthy pet dogs. For the research Beagles, 5 dogs were vaccinated with a multivalent vaccine and a rabies vaccine, 5 dogs received only the multivalent vaccine, 5 dogs received only the rabies vaccine, and 5 dogs were unvaccinated controls. The multivalent vaccine was administered at 8, 10, 12, 16, 20, 26, and 52 weeks of age and every 6 months thereafter. The rabies vaccine was administered at 16 and 52 weeks of age and then once per year. Blood was collected from all dogs at 8, 16, and 26 weeks of age and then 4 times yearly. Assays for antibodies directed against bovine and canine thyroglobulin were performed prior to and 2 weeks after each yearly vaccination. For the pet dogs, blood was collected prior to and 2 weeks after 1 vaccination. In the research Beagles, there was a significant increase in anti-bovine thyroglobulin antibodies in all vaccinated dogs, compared with control dogs. There was a significant increase in anti-canine thyroglobulin antibodies in the 2 groups of dogs that received the rabies vaccine but not in the group that received the multivalent vaccine alone. In the pet dogs, there was a significant increase in anti-canine thyroglobulin antibodies after vaccination but no significant change in anti-bovine thyroglobulin antibodies. Recent vaccination may result in increased anti-canine thyroglobulin antibodies. Whether these antibodies have a deleterious effect on canine thyroid function is unknown.

Prevalence of autoantibodies to thyroglobulin in dogs with nonthyroidal illness

Abstract Objective To evaluate a thyroglobulin autoantibody (TgAA) assay and determine a diagnostic threshold. Sample Population Serum samples from dogs with various endocrine abnormalities and from 30 obese adult female Beagles. Procedure TgAA were determined by use of the ELISA. Six experiments were done: 1, definition of positive results for TgAA using samples from normal and T3 autoantibody (T3AA) positive dogs; 2, establishment of prevalence of positive results in 91 clinically normal dogs; 3, evaluation of positive results for sera from dogs with nonthyroidal illnesses; 4, testing of samples from dogs with primary hypothyroidism but absence of T4AA or T3AA, or both; 5, determination of prevalence of false-negative results in dogs that are T4AA and/or T3AA positive, which were (18 dogs) or were not (22 dogs) receiving L-thyroxine replacement therapy; and 6, examination of thyroid biopsy specimens from 18 dogs (8 TgAA positive and 10 TgAA negative). Results Positive results were defined as at least twice (200%) the optical density of the negative-control sample. False-positive results were obtained for only 3.4% of 146 dogs with nonthyroidal illness. Thirty-seven percent of dogs with primary hypothyroidism, but no evidence of T4AA or T3AA, or both, were TgAA positive. False-negative results were found in 1 of 22 and 2 of 18 T3AA-positive dogs with and without thyroid replacement therapy, respectively. Thyroid biopsy specimens from 8 TgAA-positive dogs had evidence of lymphocytic thyroiditis, whereas those from 10 TgAA-negative dogs did not. Conclusion and Clinical Relevance The assay is sensitive and specific for identification of lymphocytic autoimmune thyroiditis in dogs, and has potential for aiding early diagnosis of thyroiditis in dogs and identifying dogs likely to perpetuate hypothyroidism in breeding programs. (Am J Vet Res 1998;59:951–955)

IgG subclasses of canine anti-erythrocyte, antinuclear and anti-thyroglobulin autoantibodies

A panel of monoclonal antibodies (mAbs) reactive with the four canine IgG subclasses (IgGI, IgG2, IgG3 and IgG4) was used to investigate the activity of IgG subclasses in autoimmune responses to erythrocytes, nuclear antigens and thyroglobulin in dogs with autoimmune disease. mAbs specific for canine IgGl and IgG4 were able to agglutinate normal dog erythrocytes coated with purified canine IgG containing each of the four subclasses. IgGl autoantibodies were demonstrated on the surface of erythrocytes from seven dogs with Coombs'-positive autoimmune haemolytic anaemia and IgG4 autoantibodies were also present in two of these cases. Serum antinuclear antibody was shown in nine dogs to be predominantly of IgGl, IgG3 and IgG4 subclasses with only one of the dogs also producing an IgG2 antinuclear antibody. The IgG subclass profile of antinuclear antibodies differed between dogs with polyarthritis and dogs with other systemic disease. In six dogs with hypothyroidism, thyroglobulin autoantibodies of subclasses IgGI, IgG2 and IgG4 predominated, but one dog also produced significant levels of IgG3 thyroglobulin autoantibodies. The mAbs are widely applicable to the study of the pathogenesis of canine autoimmune disease.

Passive Hemagglutination for Detection of Autoantibodies against Thyroglobulin in Dogs

Primary hypothyroidism in dogs is mainly caused by autoimmune thyroiditis or idiopathic follicular atrophy of the thyroid gland (Gosselin et al. 1982). Serologically, autoimmune thyroiditis can be diagnosed by detection of autoantibodies against thyroid antigens in hypothyroid dogs (Mizejewski et al. 1971, Gosselin et al. 1980). Passive hemagglutination test (PHT) has been the serological test, most widly used for detection of antibodies (Mizejewski et al. 1971, Gosselin et al. 1982, Vollset & Larsen 1987).

The identification of a specific fragment of dog thyroglobulin responsible for immunoreactivity to parafollicular cells.

This study provides new information related to our earlier finding of a thyroglobulin-like antigen in parafollicular cells. Dog thyroglobulin was saltedout with ammonium sulfate, then chromatographed on a Bio-Gel A-5m column. Four distinct 280-nm-absorbing peaks (I–IV) were observed. Antisera to each of these fractions were studied by immunodiffusion and immunoelectrophoresis and showed that the main antibody produced was against 19S thyroglobulin. Each of the antisera gave distinct immunoreactions with colloid droplets and follicular cells when stained with the immunoperoxidase bridge technique. Only the antiserum to peak I, however, gave a strong positive reaction to the parafollicular cells. Absorption of this antiserum with adequate amounts of the peak II fraction removed the reaction to colloid droplets and follicular cells, but left the reaction with parafollicular cells intact, while absorption with the peak I fraction eliminated the reaction with the parafollicular cells. The results indicate that...

Immunohistochemical study of a large molecular fragment of thyroglobulin in parafollicular cells.

Thyroglobulin-like immunoreactivity of the parafollicular cells was studied by an immunoperoxidase bridge technique using antisera against dog thyroglobulin fragments. 1. The dog parafollicular cells were specifically stained by anti-peak I (27S and larger components fraction) antiserum absorbed with peak II (19S fraction). By this method, they were easily distinguishable from the non-reactive follicular cells and colloid droplets. More sensitive staining of the parafollicular cells was possible with anti-peak I'' (larger components fraction) antiserum. The staining reactions indicated that the antigenic material responsible for immunoreactivity of the parafollicular cells was due to larger molecular components of thyroglobulin corresponding to 32S, 37S or greater than 37S, and was not due to either the 19S thyroglobulin or to the 27S iodoprotein. 2. A conspicuous decrease of the immunoreactive material in the parafollicular cells occurred in the dog after both chronically induced hypercalcemia and antithyroid drug treatment. This coincided with movement of secretory granules containing calcitonin as shown by staining with silver impregnation, HCl-basic dye, and lead-hematoxylin. 3. The antisera against larger molecular components of dog thyroglobulin showed a high degree of cross-reactivity to the parafollicular cells of most of the mammalian species investigated; rats, rabbits, hamsters, mice, cats, lions, goats, cows, and human.

Evidence for non-covalent binding of iodoaminoacids in purified thyroglobulin.

ABSTRACT In vivo 125I-labelled dog thyroglobulin was either extracted with acid acetone or subjected to gel filtration, in order to see whether the iodoaminoacids could be removed. The acetone extracts or the material adsorbed on to the Sephadex columns contained 5–16% of the total 125I-activity present in the purified protein. These fractions of radioactivity were analyzed by two dimensional chromatography and iodoaminoacids found to be present. By equilibrium experiments it was further shown that our thyroglobulin preparation would only bind thyroxine but not 3-mono- and 3,5-diiodotyrosine. A possible interpretation of these results is that at least a fraction of the iodinated compounds of thyroglobulin is linked to the protein by non-covalent bonds.

Demonstration of thyroglobulin in dog lymph.

Lymph was collected from the cervical ducts of dogs. The lymph was concentrated by dialysis to about 1/10 of initial volume, and then employed in immunoelectrophoretic studies for the detection of thyroglobulin, using rabbit antisera against dog thyroglobulin. The results showed that the lymph samples contained a substance which was immunologically identical with thyroglobulin in 6 of 7 dogs after TSH injection and in 2 of 5 dogs without TSH administration. (Endocrinology 82: 1047, 1968)

Metabolism and metabolic effects of thyroglobulin.

INJECTION of beef or hog thyroglobulin into experimental animals causes an increase in basal metabolic rate and antagonizes the action of antithyroid drugs. These effects are similar to those following the injection of thyroxine. There is yet no adequate explanation for the fact, reported by various workers1, that these thyroglobulins are more effective than can be accounted for by the liberation in the body of the thyroxine they contain. More recent observations have demonstrated the varying ability of different species to remove homologous and heterologous thyroglobulins labelled with iodine-131 from the circulation2. An attempt is now being made to correlate the metabolism of different thyroglobulins with effect on the basal metabolic rate at the same dose-level. This communication concerns the absorption, metabolism and metabolic effects in the rabbit of purified dog thyroglobulin.