Antigenic Proteins of Helicobacter pylori of Potential Diagnostic Value

Abstract

Helicobacter pylori antigen was prepared from an isolate from a patient with a duodenal ulcer. Serum samples were obtained from culture-positive H. pylori infected patients with duodenal ulcers, gastric ulcers and gastritis (n=30). As controls, three kinds of sera without detectable H. pylori IgG antibodies were used: 30 from healthy individuals without history of gastric disorders, 30 from patients who were seen in the endoscopy clinic but were H. pylori culture negative and 30 from people with other diseases. OFF-GEL electrophoresis, SDS-PAGE and Western blots of individual serum samples were used to identify protein bands with good sensitivity and specificity when probed with the above sera and HRP-conjugated anti-human IgG. Four H. pylori protein bands showed good (≥ 70%) sensitivity and high specificity (98-100%) towards anti-Helicobacter IgG antibody in culturepositive patients sera and control sera, respectively. The identities of the antigenic proteins were elucidated by mass spectrometry. The relative molecular weights and the identities of the proteins, based on MALDI TOF/ TOF, were as follows: CagI (25 kDa), urease G accessory protein (25 kDa), UreB (63 kDa) and proline/pyrroline-5-carboxylate dehydrogenase (118 KDa). These identified proteins, singly and/or in combinations, may be useful for diagnosis of H. pylori infection in patients.

Biomarkers and diagnostic tools for detection of Helicobacter pylori

“…Moreover, aberrant diagnosis and treatment may lead to drug misuse subject to unpredictable side effects. There are many immunoassays that have been developed for the diagnosis of anti-H. pylori class serum antibodies (IgG/IgM/IgA) (Khalilpour et al 2014a;Khalilpour et al 2013). The diagnosis of H. pylori infection markers via serology is the easiest noninvasive method for diagnosing an infection as it requires only a few drops of blood from the finger and the results are available in less than 5 min.…”

“…2). Out of the four H. pylori infection markers identified by Khalilpour et al, UreG, CagI, and pyroline-S-carboxylate dehydrogenase were reported for the first time (Khalilpour et al 2014a;Khalilpour et al 2012;Khalilpour et al 2013;Noordin et al 2013).…”

“…Previous researches have focused on the urease enzymes, CagA, VacA, FlaA, HspB, FlaB, and outer membrane proteins in order to quickly produce a diagnostic kit for recognition of H. pylori infection (Cremonini et al 2004;Khalilpour et al 2013;Schumann et al 2006;Zheng et al 2002). Although some bacterial factors such as the heat shock protein, H. pylori adhesin (HpaA), and flagella have also been identified as pathogenic determinants, understanding the function of H. pylori cellular components in the pathogenesis of gastric disorders requires further investigation (Park et al 2006).…”

“…This cellular destruction alerts the immune system to the fact that there is something occurring in the interior of the stomach. Khalilpour et al (2013) Cytokines, produced by the injured cells send signals to the immune system, leading to tissue infiltration of immune cells.…”

Lateral Flow Test Using Echinococcus granulosus Native Antigen B and Comparison of IgG and IgG4 Dipsticks for Detection of Human Cystic Echinococcosis

“…SDS-PAGE and Western blotting were performed as described previously. 24 Each AgB batch was mixed 1:4 with 5 + sample buffer (0.3125 M TrisHCl [pH 6.8], 10% SDS, 50% glycerol, 0.005% bromophenol blue, and 25% 2-mercaptoethanol), and 20 μg sample/well was electrophoresed in a 12% (vol/vol) SDS-PAGE gel in fresh running buffer (0.3% Tris, 1.44% glycine, and 0.1% SDS [pH 8.3]) at a constant current of 100 V for 110 minutes. Proteins were transferred from the gel onto a nitrocellulose membrane using the Trans-Blot SD Semi-Dry Electrophoretic Transfer Cell (Bio Rad) at a constant current of 12 A for 30 minutes.…”