Abstract
BackgroundHelicobacter pylori is a human pathogen and during the process of infection, antigens from the bacterium elicit strong host humoral immune responses. In our previous report, native H. pylori UreG protein showed good reactivity with sera from H. pylori patients. This study was aimed at producing the recombinant form of the protein (rUreG) and determining its seroreactivities.MethodsThe coding sequence of H. pylori UreG was cloned and the recombinant protein expressed and purified by affinity chromatography using nickel nitrilotriacetic acid (Ni-NTA) resin. The antigenicity of rUreG to detect H. pylori specific antibodies was determined by western blot, using HRP-conjugated anti-human IgG and IgA antibodies as probes. A total of 70 sera, comprising 30 positive and 40 control serum samples, were used. The positive sera were from culture-positive H. pylori-infected patients with duodenal ulcers, gastric ulcers, or gastritis. The control sera comprised three types of samples without detectable H. pylori antibodies, i.e. healthy individuals (with no history of gastric disorders) (n = 10); patients who attended an endoscopy clinic (because of gastrointestinal complaints) but were H. pylori culture negative (n = 20); and people with other diseases (n = 10). Additionally, hyperimmune mice serum against rUreG was raised and tested with the native and recombinant UreG protein.ResultsThe ureG gene fragment was successfully cloned and expressed in both soluble and insoluble forms. Western blots on rUreG protein showed 70% (21/30) and 60% (18/30) reactivity with patients’ sera when probed with HRP-conjugated anti-human IgG and IgA antibodies, respectively; and the combination of the IgG and IgA western blots showed reactivity of 83.3% (25/30). By comparison, 97.5% and 92.5% of the control sera showed no reactivity when probed with HRP-conjugated anti-human IgG and IgA antibodies, respectively. Both the H. pylori lysate antigen and rUreG protein displayed a distinctive band at the expected molecular weight when probed with the hyperimmune mice serum.ConclusionThe rUreG protein was successfully cloned and expressed and showed good reactivity with H. pylori culture-positive patients’ sera and no reactivity with most control sera. Thus, the diagnostic potential of this recombinant protein merits further investigation.
Highlights
Helicobacter pylori is a human pathogen and during the process of infection, antigens from the bacterium elicit strong host humoral immune responses
During the process of H. pylori infection, the antigens secreted from the bacterium elicit strong antibody responses in the host; secreted H. pylori antigens may be studied as potential infection biomarkers [6]
We report the cloning and expression of the UreG coding sequence and determination of its seroreactivity
Summary
Helicobacter pylori is a human pathogen and during the process of infection, antigens from the bacterium elicit strong host humoral immune responses. The discovery and successful culture of H. pylori by Marshall and Warren in 1982 revolutionized the diagnosis and treatment of gastroduodenal disease [2]. This organism has been categorized as a class I carcinogen by the World Health Organization [3,4] and direct evidence of carcinogenesis was recently demonstrated in an animal model. During the process of H. pylori infection, the antigens secreted from the bacterium elicit strong antibody responses in the host; secreted H. pylori antigens may be studied as potential infection biomarkers [6]. Various H. pylori proteins had been employed as infection markers for diagnosis, such as CagA, VacA, HspB, FlaA, FlaB, and UreC [7,8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
