Gardas A, Domek H, Czarnocka B
Biochemistry Department, Medical Center of Postgraduate Education, Warsaw, Poland.
Autoimmunity. 1990;7(2-3):149-56. doi: 10.3109/08916939008993387.
The effect of disulphide bridges reduction of the microsomal antigen (Mic-Ag) and thyroid peroxidase (TPO) by dithiotreitol (DTT) has been investigated. The reaction of all 67 tested sera from untreated hyperthyroid Graves' and from 22 Hashimoto's patients with high microsomal antibodies (aAb) titer was diminished by 90-95% by DTT, at pH 9.6. The remaining 5-10% of the activity was not destroyed by DTT. The residual Mic-Ag after DTT reduction was able to inhibit the binding of all 45 Graves' and 22 Hashimoto's tested aAb's to the native microsomal antigen by 100% at high concentration. Reaction of affinity purified TPO with two monoclonal antibodies (mAb) were diminished by 80% to 95% by DTT pretreatment, while the reaction of one mAb with TPO was only slightly affected. The reaction of TPO and Mic-Ag with rabbit polyclonal anti-TPO serum (rabbit a TPO) was diminished by 60% by DTT pretreatment. The immunological reactivity of TPO with aAb's was diminished by 65% after DTT pretreatment. The microsomal antigen-aAb's complex was not destroyed by DTT. Results presented in this paper suggest conformational epitope structure of the Mic-Ag recognized by aAb's in patients with thyroid autoimmune disease (AITD).
已研究了二硫苏糖醇（DTT）对微粒体抗原（Mic-Ag）和甲状腺过氧化物酶（TPO）中二硫键的还原作用。在pH 9.6条件下，DTT使来自未经治疗的甲状腺功能亢进Graves病患者的67份检测血清以及来自22例微粒体抗体（aAb）滴度高的桥本氏病患者的所有血清反应降低了90 - 95%。其余5 - 10%的活性未被DTT破坏。DTT还原后的残余Mic-Ag在高浓度时能够100%抑制所有45份Graves病和22份桥本氏病检测aAb与天然微粒体抗原的结合。亲和纯化的TPO与两种单克隆抗体（mAb）的反应经DTT预处理后降低了80%至95%，而一种mAb与TPO的反应仅受到轻微影响。TPO和Mic-Ag与兔抗TPO多克隆血清（兔抗TPO）的反应经DTT预处理后降低了60%。DTT预处理后，TPO与aAb的免疫反应性降低了65%。微粒体抗原 - aAb复合物未被DTT破坏。本文给出的结果提示甲状腺自身免疫性疾病（AITD）患者中aAb识别出的Mic-Ag的构象表位结构。
