Analysis of triiodothyronine and thyroxine-binding autoantibodies in @entity1573 susceptible to XXXX .

@entity1669 @entity1573 @entity2445
This report reveals a surprisingly high incidence of thyroid hormone (T3 and T4) autoantibodies ( @entity2445 ) and thyroglobulin autoantibodies in a closed flock of untreated Cornell strain (CS) White Leghorn @entity1573 . This flock is closely related to the Obese strain @entity1573 , which develops a severe spontaneous @entity1669 . A sensitive electrophoretic autoradiographic assay for @entity2445 was developed. This assay was applied to the study of autoantibodies to T3 and T4 in the sera of adult female CS @entity1573 . Of 109 females, 29.4% had antibodies to T3 and 18.4% had antibodies to T4. The incidence of thyroglobulin antibodies, determined by passive hemagglutination, was 15.6%. The presence of @entity2445 affected RIA measurements because serum T3 and T4 hormone concentrations appeared elevated in those birds with moderate to high antibody levels. There was major variance in the electrophoretic heterogeneity of the @entity2445 from individual @entity1573 ; i.e., some of the sera contained antibodies to T3 or T4 that appeared to be monoclonal, whereas other sera exhibited polyclonal multi-banded patterns. To determine if antibodies reactive with T3 and T4 (which are haptens) were generated by antibody responses to the T3/T4 sites on the thyroglobulin molecule, competitive binding assays were performed to determine the relative binding affinities of the antibodies for the haptens (T3/T4) and the "hapten-conjugate" (thyroglobulin). In these assays, thyroglobulin competed with the haptens, thus supporting the above hypothesis.
