Characterization and sequencing of a 40-amino-acid peptide from human thyroglobulin inducing experimental autoimmune thyroiditis.
Characterization and sequencing of a 40-amino-acid peptide from human thyroglobulin inducing experimental autoimmune thyroiditis.
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来自诱导实验性自身免疫性甲状腺炎的人甲状腺球蛋白的 40 个氨基酸肽的表征和测序。
作者：
B. Texier;C. Bedin;H. Tang;L. Camoin;C. Laurent‐Winter;J. Charreire
我们之前证明了：a）细胞毒性T细胞杂交瘤（HTC 2）能够诱导用猪甲状腺球蛋白（pTg）或来自小于10 kDa的pTg的胰蛋白酶片段（TF）（M（r））脉冲的同系巨噬细胞的裂解，并且B）这些低M（r）pTg TF包括致病性表位，因为它们注射到CBA/J小鼠中诱导实验性自身免疫性甲状腺炎典型的甲状腺淋巴细胞浸润。因此，对来自pTg小于10 kDa M（r）的TF制剂进行生物化学分析，并测试表征的肽被HTC 2细胞识别或不被识别的能力。所选肽的测序显示与人甲状腺球蛋白（hTg）的一部分70%的序列同源性。由于缺乏已发表的pTg序列，我们合成了一个与hTg部分相似的40个氨基酸的肽（F40 D）。该F40 D肽能够在CBA/J小鼠甲状腺中产生淋巴细胞浸润，如天然pTg分子一样。虽然在pTg或F40 D免疫的小鼠中淋巴细胞浸润是相似的，但仅在用pTg免疫的小鼠中可检测到针对pTg或针对hTg的自身抗体。与此相反，F40 D肽诱导EAT的小鼠血清中抗F40 D肽的自身抗体水平显著增加。这种高度疏水的肽显示出4，492 kDa的M（r）;它位于甲状腺球蛋白分子的第二-三分之一的末端，迄今为止代表了诱导实验性自身免疫性甲状腺炎的hTg分子的独特序列。
We previously demonstrated that: a) a cytotoxic T cell hybridoma (HTC2) was able to induce lysis of syngeneic macrophages pulsed with either porcine thyroglobulin (pTg) or the tryptic fragments (TF) from pTg less than 10 kDa (M(r)) and that b) these low M(r) pTg TF included pathogenic epitopes because their injection into CBA/J mice induces thyroid lymphocytic infiltration typical of experimental autoimmune thyroiditis. Therefore the biochemical analysis of the TF preparation from pTg less than 10 kDa M(r) was undertaken and the characterized peptides were tested for their ability to be recognized or not by HTC2 cells. The sequencing of the selected peptides showed a 70% sequence homology with a portion of human thyroglobulin (hTg). The lack of a published sequence of pTg led us to synthesize a 40-amino acid peptide (F40D) similar to that portion of hTg. This F40D peptide was able to generate lymphocytic infiltrations in CBA/J mice thyroid glands, as was the native pTg molecule. Although the lymphocytic infiltrations were similar in the pTg or F40D-immunized mice, auto-antibodies to pTg or to hTg were only detectable in mice immunized with pTg. In contrast, autoantibodies levels to F40D peptide were significantly increased in serum from mice in which EAT had been induced by the F40D peptide. This highly hydrophobic peptide shows a M(r) of 4,492 kDa; it is located at the end of the second-third of the thyroglobulin molecule and up to now represents a unique sequence from the hTg molecule inducing experimental autoimmune thyroiditis.