Binding assay for thyrotropin receptor autoantibodies using the recombinant receptor protein.
We have characterized a transfected Chinese hamster ovary cell line, JP09, which expresses high levels of the human TSH receptor (TSH-R). Based on a theoretical biological activity for TSH of 40 IU/mg, JP09 has approximately 90,000 receptors per cell, having a dissociation constant of 1.64 x 10(3) mU/L or 1.47 x 10(-9) mol/L. We have used JP09 to prepare solubilized TSH-Rs which have formed the basis of a binding assay for thyroid-binding inhibiting immunoglobulins in unfractionated sera. We have compared the JP09 assay with the TRAK assay (which is based on solubilized porcine TSH-R) and found a highly positive correlation between the two assays, r = 0.83 P < 0.0001, in 55 sera from patients with autoimmune thyroid disease. JP09 can be adapted to growth in suspension culture, permitting large scale production. The tracer in the assay is bovine [125I]TSH; surprisingly, despite the use of a hTSH-R, hTSH had no effect on the binding of the tracer up to 10(3) mU/L and only a minor effect at 10(4) mU/L.
Institut de Recherche Interdisciplinaire en Biologie Humaine et Nucleaire, Université Libre de Bruxelles, Hôpital Erasme, Belgium.
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S
Costagliola
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S
Swillens
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P
Niccoli
J E
JE
Dumont
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Vassart
M
M
Ludgate
D000818:Animals; D000906:Antibodies / Q000378:metabolism*; D001323:Autoantibodies / Q000378:metabolism*; D016466:CHO Cells / Q000378:metabolism; D006224:Cricetinae; D003584:Cytological Techniques; D018828:Immunoglobulins, Thyroid-Stimulating; D011989:Receptors, Thyrotropin / Q000378:metabolism*; D011994:Recombinant Proteins; D012995:Solubility; D013535:Suspensions; D013552:Swine
D000906:Antibodies; D001323:Autoantibodies; D018828:Immunoglobulins, Thyroid-Stimulating; D011989:Receptors, Thyrotropin; D011994:Recombinant Proteins; D013535:Suspensions