Minich Waldemar B, Lenzner Cornelia, Bergmann Andreas, Morgenthaler Nils G
MiLo GmbH, B.R.A.H.M.S. AG, Biotechnology Center Hennigsdorf/Berlin, D-16761 Hennigsdorf, Germany.
J Clin Endocrinol Metab. 2004 Jan;89(1):352-6. doi: 10.1210/jc.2003-030823.
We developed a coated tube assay to discriminate TSH-receptor-stimulating autoantibodies [thyroid-stimulating antibodies (TSAb)] from those autoantibodies blocking TSH binding without intrinsic activation [thyroid-blocking antibodies (TBAb)]. The wild-type TSH receptor in the TSH binding-inhibitory assay was exchanged for a chimeric receptor where a TSAb epitope (amino acids 8-165) was replaced by comparable LH-R residues. Binding of (125)I-labeled TSH to this chimera could be inhibited by sera containing TBAb up to 95%. Sera from 316 patients with Graves' disease and 17 with autoimmune thyroid disease were grouped according to their bioassay activity. At the decision threshold, the chimera A assay had a sensitivity of 78.0% for TBAb with a specificity of 90.2%. In detail, 19 of 22 (86.4%) TBAb sera and 15 of 23 (65.2%) TSAb/TBAb sera were positive but only 32 of 216 (14.0%) TSAb sera and 5 of 72 (6.9%) bioassay negative sera. There was a weak but significant positive correlation (r = 0.46) between the chimera assay and the bioassay for TBAb. This is the first report of a coated tube assay for the determination of TBAb employing an adaptation of the TSH binding-inhibitory format, which could be a useful alternative to the bioassay.
我们开发了一种包被管测定法，以区分促甲状腺激素受体刺激自身抗体[甲状腺刺激抗体（TSAb）]与那些阻断促甲状腺激素结合但无内在激活作用的自身抗体[甲状腺阻断抗体（TBAb）]。在促甲状腺激素结合抑制试验中，将野生型促甲状腺激素受体替换为一种嵌合受体，其中TSAb表位（氨基酸8 - 165）被相应的促黄体生成素受体（LH - R）残基取代。含TBAb的血清可抑制（125）I标记的促甲状腺激素与该嵌合体的结合，抑制率高达95%。根据生物测定活性，对316例格雷夫斯病患者和17例自身免疫性甲状腺疾病患者的血清进行分组。在判定阈值时，嵌合体A测定法对TBAb的敏感性为78.0%，特异性为90.2%。具体而言，22份TBAb血清中的19份（86.4%）以及23份TSAb/TBAb血清中的15份（65.2%）呈阳性，但216份TSAb血清中只有32份（14.0%）以及72份生物测定阴性血清中有5份（6.9%）呈阳性。嵌合体测定法与TBAb生物测定法之间存在微弱但显著的正相关（r = 0.46）。这是首次报道采用促甲状腺激素结合抑制形式的改良方法来测定TBAb的包被管测定法，它可能是生物测定法的一种有用替代方法。
