B cell epitopes of gliadin
B cell epitopes of gliadin
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DOI：
10.1046/j.1365-2249.2000.01312.x
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发表时间：
2000-08-01
影响因子：
4.6
通讯作者：
Mothes, T
中科院分区：
文献类型：
--
作者：
Osman, AA;Günnel, T;Mothes, T
筛选噬菌体展示的十二肽文库和跨越α-和γ-型麦醇溶蛋白的完整序列并在六个氨基酸中重叠的合成八肽（pepscan），用于结合人麦醇溶蛋白抗体（阿加）。噬菌体展示实验导致四个序列的识别与显着更高的频率与提高IgA-AGA滴度的血清比对照血清。所有这些肽都含有核心序列PEQ。Pepscan实验揭示了阿加与五个主要区域的结合：（i）QXQPFP（与IgG和伊加结合，X代表P、Q和L）;（ii）IPEQ（IgG）和WQIPEQ（伊加）;（iii）FFQP（IgG）和QGXQQP（伊加，X代表F和S）;（iv）PQQLPQ（IgG和伊加），全部在α型麦醇溶蛋白中;和（v）QPQQPF（IgG和伊加）在γ型麦醇溶蛋白中。在两个序列（QPQQPF和QQQPFP）中，Q被E取代分别导致QPEQPF和QEQPFP，显著增加了来自活检证实或疑似腹腔疾病（CoD）患者血清的阿加结合，所有患者均为肌内膜抗体（EmA）阳性。与此相反，结合的血清与高阿加滴度的EMA阴性患者（辅酶D和疱疹样皮炎除外）没有增强这种取代。因此，针对这些经修饰的表位的阿加可被认为对CoD具有特异性。这是第一个研究表明，麦胶蛋白的脱酰胺提高了CoD患者的阿加反应性。
A phage displayed dodecapeptide library and synthetic octapeptides spanning the complete sequence of alpha- and gamma-type gliadin and overlapping in six amino acids (pepscan) were screened for binding to human gliadin antibodies (AGA). Phage display experiments led to four sequences recognized with significantly higher frequency by sera with raised IgA-AGA titres than by control sera. All these peptides contained the core sequence PEQ. Pepscan experiments revealed binding of AGA to five prominent regions: (i) QXQPFP (binding to IgG and IgA, X representing P, Q, and L); (ii) IPEQ (IgG) and WQIPEQ (IgA); (iii) FFQP (IgG) and QGXFQP (IgA, X representing F and S); (iv) PQQLPQ (IgG and IgA), all in alpha-type gliadin; and (v) QPQQPF (IgG and IgA) in gamma-type gliadin. In two of the sequences (QPQQPF and QQQPFP), substitution of Q by E resulting in QPEQPF and QEQPFP, respectively, increased significantly binding of AGA from sera of patients with biopsy-proven or suspected coeliac disease (CoD), all positive for endomysium antibodies (EmA). In contrast, binding of sera with high AGA titre from EmA-negative patients (CoD and dermatitis herpetiformis excluded) was not enhanced by this substitution. Thus, AGA directed against these modified epitopes can be regarded as specific for CoD. This is the first study demonstrating that deamidation of gliadin improves reactivity of AGA of CoD patients.