Czarnocka B, Janota-Bzowski M, McIntosh R S, Asghar M S, Watson P F, Kemp E H, Carayon P, Weetman A P
Department of Biochemistry, Medical Center of Postgraduate Education, Warsaw, Poland.
J Clin Endocrinol Metab. 1997 Aug;82(8):2639-44. doi: 10.1210/jcem.82.8.4124.
Patients with autoimmune thyroid disease frequently have high affinity antibodies to thyroid peroxidase (TPO), although the role they play in disease pathogenesis is not known. We have previously prepared 37 monoclonal anti-TPO IgG kappa Fab fragments from two patients with Hashimoto's thyroiditis and demonstrated the similarity of these Fab sequences to those published previously, mainly derived from patients with Graves' disease. In this paper, we described epitope mapping of these Fabs using a previously characterized panel of murine monoclonal antibody (mAb) and show that the Fabs bind to two neighboring epitopes on native TPO. Although the epitope-mapping method differs from that used to characterize previously published TPO-reactive Fab sequences, it indicates a similarly restricted response to neighboring epitopes in both Graves' disease and Hashimoto's thyroiditis. The epitope mapping included mAb 47, which binds to a linear TPO peptide of known sequence in addition to native TPO. Although TPO-reactive Fab did not inhibit the binding of mAb 47, mAb 47 did inhibit the binding of Fab, indicating the likely site of the immunodominant region on native TPO. These results confirm the restricted nature of TPO antibody and further delineate the immunodominant region of native TPO as defined by the mAb.
自身免疫性甲状腺疾病患者常常具有高亲和力的甲状腺过氧化物酶（TPO）抗体，尽管它们在疾病发病机制中所起的作用尚不清楚。我们之前从两名桥本甲状腺炎患者中制备了37种单克隆抗TPO IgG κ Fab片段，并证明这些Fab序列与先前发表的序列相似，先前发表的序列主要来自格雷夫斯病患者。在本文中，我们使用一组先前已鉴定的鼠单克隆抗体（mAb）描述了这些Fab的表位作图，并表明这些Fab与天然TPO上的两个相邻表位结合。尽管表位作图方法与用于鉴定先前发表的TPO反应性Fab序列的方法不同，但它表明在格雷夫斯病和桥本甲状腺炎中对相邻表位的反应同样受限。表位作图包括mAb 47，它除了与天然TPO结合外，还与已知序列的线性TPO肽结合。尽管TPO反应性Fab不抑制mAb 47的结合，但mAb 47确实抑制Fab的结合，这表明天然TPO上免疫显性区域的可能位点。这些结果证实了TPO抗体的受限性质，并进一步描绘了由mAb定义的天然TPO的免疫显性区域。
