The CagA protein one of the key virulence factors of Helicobacter pylori plays an important role in the pathogenesis of peptic ulcer diseases. Unfortunately the cagA gene status can only be determined by PCR while serology is an alternative approach to detect antigens or antibodies. Our aim is to detect the CagA antigen in sera of infected subjects by the development of an in-house capture ELISA test. Gastric antral biopsies and serum samples were collected from 63 patients. PCR was used to determine the cagA status. Our previously developed recombinant CagA protein and monoclonal antibody were used for setting up the capture ELISA test. H. pylori positive [(38 gastritis, 14 duodenal ulcers (DU), 11 gastric ulcer (GU)] patients were determined by PCR. The cagA gene was detected in 21 (55%) of gastritis, 11 (78%) of DU and 7 (60%) of GU patients. The reagents used in setting up the capture ELISA test following optimization displayed high performance. This study showed that our developed in-house capture ELISA has the potential to detect the CagA antigen at very low concentrations even though not detected in our H. pylori infected patients sera but we are also intended to use it in saliva and stool samples.

CagA蛋白是幽门螺杆菌的关键毒力因子之一，在消化性溃疡疾病的发病机理中起着重要作用。不幸的是，cagA基因状态只能通过PCR来确定，而血清学是检测抗原或抗体的另一种方法。我们的目标是通过内部捕获ELISA测试的开发来检测感染受试者血清中的CagA抗原。从63例患者中收集胃窦活检和血清样本。PCR用于确定cagA状态。我们先前开发的重组CagA蛋白和单克隆抗体用于建立捕获ELISA测试。幽门螺杆菌PCR检测阳性[（38例胃炎，14例十二指肠溃疡（DU），11例胃溃疡（GU）]。在21例胃炎（55％），11例胃溃疡（78％）和7例胃炎中检测到cagA基因。60％的GU病人。经过优化后用于建立捕获ELISA测试的试剂表现出很高的性能；这项研究表明，我们开发的内部捕获ELISA可以检测非常低浓度的CagA抗原，即使未检测到在我们的幽门螺杆菌感染患者血清中，但我们也打算将其用于唾液和粪便样本中。