Institute of Scientific Research, Faculty of Medicine, Oita University, Oita, Japan.
APMIS. 2009 Dec;117(12):893-9. doi: 10.1111/j.1600-0463.2009.02548.x.
Molecular biological and epidemiological studies have suggested that Helicobacter pylori producing East Asian CagA protein variant is more virulent than that producing Western CagA. In the present study, we developed and validated an enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody specifically recognizing East Asian CagA-positive H. pylori. A total of 32 H. pylori strains were tested and the data were subjected to receiver-operator characteristic (ROC) curve analysis. The accuracy of the test, determined by calculating the area under the curve, was 0.96, which indicated a high level of accuracy. At the ROC optimized cutoff, the sensitivity and specificity of our ELISA method were 88.0% and 100%, respectively. The validated ELISA showed good performance in terms of sensitivity and specificity. These results suggest that this test is suitable for the diagnostic detection of East Asian CagA carrying strains. We also analyzed the localization of the CagA protein in H. pylori-infected gastric mucosa with fluorescence immunohistochemistry, and found that CagA protein expression was up-regulated by adhesion to epithelial cells.
分子生物学和流行病学研究表明，产生东亚 CagA 蛋白变异型的幽门螺杆菌比产生西 CagA 蛋白变异型的幽门螺杆菌更具毒性。在本研究中，我们开发并验证了一种使用单克隆抗体特异性识别东亚 CagA 阳性幽门螺杆菌的酶联免疫吸附测定（ELISA）。共检测了 32 株幽门螺杆菌菌株，并对数据进行了受试者工作特征（ROC）曲线分析。通过计算曲线下面积确定了该检测的准确性，准确性为 0.96，表明具有很高的准确性。在 ROC 优化的截止值下，我们的 ELISA 方法的灵敏度和特异性分别为 88.0%和 100%。验证后的 ELISA 在灵敏度和特异性方面表现出良好的性能。这些结果表明，该检测方法适用于东亚 CagA 携带菌株的诊断检测。我们还通过荧光免疫组织化学分析了感染胃黏膜中 CagA 蛋白的定位，发现 CagA 蛋白的表达在与上皮细胞黏附后被上调。
