Designing a novel ELISA method based on CagA, NapA recombinant antigens to increase sensitivity and specificity of Helicobacter pylori whole cell antigen detection.

Abstract

In this research, we designed a direct Enzyme Linked Immunoassay method to detect Helicobacter pylori antigens in stool specimens. Helicobacter pylori infection as the worldwide problem is related to many gastrointestinal disorders such as gastritis, gastric cancer, non-ulcer disease, peptic ulcer disease and duodenal ulcer. We produced and purified recombinant CagA and NapA antigens in Escherichia coli and extracted their antibodies from a panel of positive sera specimens. We designed a novel enzyme linked immunoassay direct method in combination with the whole cell for the qualitative and quantitative detection of Helicobacter pylori antigens in human stool. Assay performance was evaluated by histopathology staining and urease activity. The sensitivity and specificity of assay was determined as 91.7 [95% confidence interval: 89.3-95.6%] and 93.1% [95% CI: 91.2-96.4%], respectively. Novel ELISA exhibits enhanced sensitivity and specificity of Helicobacter pylori detection in comparison with another commercially available kit. Combination of the recombinant antigens and whole cell of Helicobacter pylori in immunoassay designing is a new approach about early diagnosis, treatment and fallowing up of the Helicobacter pylori infected patients, especially in peptic cancer cases.