Epitope peptides of Helicobacter pylori CagA antibodies from sera by whole-peptide mapping
Epitope peptides of Helicobacter pylori CagA antibodies from sera by whole-peptide mapping
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通过全肽图谱从血清中获取幽门螺杆菌 CagA 抗体的表位肽
DOI：
10.1007/s00535-019-01584-8
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
Shamshul Ansari ; Junko Akada; Yuichi Matsuo; Seiji Shiota; Yoko Kudo; Tadayoshi Okimoto; Kazunari Murakami; Yoshio Yamaoka
中科院分区：
文献类型：
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作者：
Ansari Shamshul;Yamaoka Yoshio;Shamshul Ansari ; Junko Akada; Yuichi Matsuo; Seiji Shiota; Yoko Kudo; Tadayoshi Okimoto; Kazunari Murakami; Yoshio Yamaoka
背景幽门螺杆菌aga是一种免疫优势蛋白，可用于诊断幽门螺杆菌阳性菌株的感染。研究能够检测血清抗CagA抗体的肽表位对了解CagA免疫原性具有重要意义。方法对171例日本患者血清进行抗原表位定位研究。从CagA一致序列中设计了87个肽段，并用于ELISA协议检测血清样品。测定和比较反应抗caga IgG对特定肽的量。结果两种肽（c7-NNTEPIYAQVNKKKAGQAT和c8-AGQATSPEEPIYAQVAKKV）在h中具有较强的反应活性。感染组。有趣的是，这两种肽分别含有众所周知的EPIYA-A和EPIYA-B区域，它们是三个CagA磷酸化结构域中的两个。这些肽的酪氨酸磷酸化降低了它们在大多数血清中的反应性。此外，额外的多肽定位和嵌合肽实验表明，两个epiya基序的右侧区域的氨基酸（QV和KK）是它们具有强反应性的必要条件，而含有不同侧氨基酸的第三个epiya基序肽（c12-GRSASPEPIYATIDFDEA）在大多数情况下没有反应性。结论这两种活性肽组成的氨基酸序列是CagA重要的免疫原区，为建立基于新一代肽的CagA诊断方法奠定了基础。
BackgroundHelicobacter pyloriCagA has been found to be immuno-dominant protein and utilized for the diagnosis of the infection withcagA-positive strains. It is important to characterize the peptide epitopes capable of detecting serum anti-CagA antibodies to understand CagA immunogenicity.MethodsSera from 171 Japanese patients were subjected for the epitope mapping study. Eighty seven peptides were designed from the CagA consensus sequence and were used for ELISA protocol to test the serum samples. The reacting anti-CagA IgG amounts to specific peptides were measured and compared.ResultsThe study revealed a strong reactivity of two peptides (c7-NNTEPIYAQVNKKKAGQAT and c8-AGQATSPEEPIYAQVAKKV) inH. pylori-infected group. Interestingly, these two peptides contained the well-known EPIYA-A and EPIYA-B region, respectively, which are two out of three CagA phosphorylation domains. Tyrosine-phosphorylation of these peptides reduced their reactivity in most sera. Moreover, additional peptides’ mapping and chimeric-peptides’ experiments indicated that the amino acids (QV and KK) accommodated in right-side flanking regions of both EPIYA-motifs were essential for their strong reactivity, whereas the third EPIYA-motif containing peptide (c12-GRSASPEPIYATIDFDEA) with differing flanking amino acids was not reactive in most cases.ConclusionsOur results suggest that the amino acid sequences constituted in the two reactive peptides are the important immunogenic regions of CagA which would be useful to develop next-generation peptide-based diagnostic assays.