Anti-TSH antibody with high specificity to human TSH in sera from a patient with Graves' disease: its isolation from, and interaction with, TSH receptor antibodies.
A patient with thyrotoxic Graves' disease had an apparent measurable level of serum TSH (2.5 microU/ml) by double-antibody radioimmunoassay (RIA). The serum IgG bound with both [125I]human(h)TSH and [125I]bovine(b)TSH. The [125I]hTSH binding was more effectively displaced by human than bovine TSH, whereas [125I]bTSH binding was displaced exclusively by bTSH. Scatchard analyses revealed that [125I]hTSH binding showed two components, whereas [125I]bTSH binding had only one component. Serum TSH determined by RIA became undetectable 21 months after antithyroid drug treatment with a parallel decrease of [125I]hTSH binding IgG activity. Four thyrotrophin binding inhibitory immunoglobulins (TBII) from other patients did not interfere with the binding of the patient's serum to [125I]h- or bTSH. Furthermore, the in-vitro thyroid stimulating activities of three thyroid stimulating antibodies (TSAb) were not affected by the addition of this patient's IgG. On the other hand, this patient's Ig (3 mg/ml) abolished the in-vitro thyroid stimulation by bTSH (100 microU/ml), but did not affect that by hTSH (100 microU/ml). The anti-hTSH antibody, TSH receptor antibody and anti-bTSH antibody in the serum, which contains TSAb as well as anti-TSH antibodies, could be partially purified by hTSH-agarose and subsequently by guinea pig fat cell membrane affinity absorptions. However, the anti-hTSH antibody fraction obtained had both hTSH binding activity and thyroid stimulating activity, and this fraction did not show any inhibitory effect on the in-vitro thyroid stimulation of autologous TSH receptor antibody or hTSH. The possible significance of anti-TSH antibodies is discussed.
D000328:Adult; D000818:Animals; D000918:Antibody Specificity; D001323:Autoantibodies / Q000032:analysis* / Q000302:isolation & purification; D002417:Cattle; D006111:Graves Disease / Q000097:blood / Q000276:immunology*; D006801:Humans; D008297:Male; D011989:Receptors, Thyrotropin / Q000276:immunology*; D013972:Thyrotropin / Q000097:blood / Q000276:immunology*
D001323:Autoantibodies; D011989:Receptors, Thyrotropin; D013972:Thyrotropin