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Characterization of a novel Helicobacter pylori East Asian-type CagA ELISA for detecting patients infected with various cagA genotypes.

ABSTRACT: Currently, Western-type CagA is used in most commercial Helicobacter pylori CagA ELISA kits for CagA detection rather than East Asian-type CagA. We evaluated the ability of the East Asian-type CagA ELISA developed by our group to detect anti-CagA antibody in patients infected with different cagA genotypes of H. pylori from four different countries in South Asia and Southeast Asia. The recombinant CagA protein was expressed and later purified using GST-tag affinity chromatography. The East Asian-type CagA-immobilized ELISA was used to measure the levels of anti-CagA antibody in 750 serum samples from Bhutan, Indonesia, Myanmar, and Bangladesh. The cutoff value of the serum antibody in each country was determined via Receiver-Operating Characteristic (ROC) analysis. The cutoff values were different among the four countries studied (Bhutan, 18.16 U/mL; Indonesia, 6.01 U/mL; Myanmar, 10.57 U/mL; and Bangladesh, 6.19 U/mL). Our ELISA had better sensitivity, specificity, and accuracy of anti-CagA antibody detection in subjects predominantly infected with East Asian-type CagA H. pylori (Bhutan and Indonesia) than in those infected with Western-type CagA H. pylori predominant (Myanmar and Bangladesh). We found positive correlations between the anti-CagA antibody and antral monocyte infiltration in subjects from all four countries. There was no significant association between bacterial density and the anti-CagA antibody in the antrum or the corpus. The East Asian-type CagA ELISA had improved detection of the anti-CagA antibody in subjects infected with East Asian-type CagA H. pylori. The East Asian-type CagA ELISA should, therefore, be used in populations predominantly infected with East Asian-type CagA.

SUBMITTER: Doohan D

PROVIDER: S-EPMC6983352 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature

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Characterization of a novel Helicobacter pylori East Asian-type CagA ELISA for detecting patients infected with various cagA genotypes.

Doohan Dalla D Miftahussurur Muhammad M Matsuo Yuichi Y Kido Yasutoshi Y Akada Junko J Matsuhisa Takeshi T Yee Than Than TT Htet Kyaw K Aftab Hafeza H Vilaichone Ratha-Korn RK Mahachai Varocha V Ratanachu-Ek Thawee T Tshering Lotay L Waskito Langgeng Agung LA Fauzia Kartika Afrida KA Uchida Tomohisa T Syam Ari Fahrial AF Rezkitha Yudith Annisa Ayu YAA Yamaoka Yoshio Y

Medical microbiology and immunology 20190923 1

Currently, Western-type CagA is used in most commercial Helicobacter pylori CagA ELISA kits for CagA detection rather than East Asian-type CagA. We evaluated the ability of the East Asian-type CagA ELISA developed by our group to detect anti-CagA antibody in patients infected with different cagA genotypes of H. pylori from four different countries in South Asia and Southeast Asia. The recombinant CagA protein was expressed and later purified using GST-tag affinity chromatography. The East Asian- ...[more]

PMID: 31549252

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Project description:BackgroundChronic infection by Helicobacter pylori strains expressing cytotoxin-associated gene A (CagA) are the strongest risk factor for gastric cancer. CagA can be classified into East Asian-type and Western-type (CagAE and CagAW), with CagAE being more closely associated with gastric cancer. This study aimed to investigate the impact of CagAE on intracellular signaling pathways to explain its high oncogenicity.ResultsMutant H. pylori strains expressing either CagAE or CagAW were generated by transforming CagAE/W-expression plasmid into CagA-deleted G27 strain (G27ΔCagA). In human gastric epithelial cells (GES-1) infection, CagAE induced more severe cytopathic changes, including higher interleukin-8 (IL-8) secretion, reduced cell viability, more pronounced "hummingbird phenotype" alterations, and increased cell migration and invasion compared to CagAW. Transcriptome analysis revealed that CagAE had a stronger effect on the up-regulation of key intracellular processes, including tumor necrosis factor-ɑ (TNF-ɑ) signal pathway via nuclear factor kappa-B (NF-κB), inflammatory response, interferon-γ (IFN-γ) response, hypoxia, ultraviolet (UV) response, and Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) signaling. A significant upregulation of hypoxia-related genes was a notable feature of CagAE. GES-1 cells infected with CagAE exhibited more severe intracellular hypoxia and higher levels of reactive oxygen species (ROS) than those infected with CagAW. Inhibition of hypoxia-inducible factor-1α (HIF-1α), which blocks hypoxia signaling, mitigated CagAE-induced cell migration, emphasizing the role of hypoxia in mediating CagAE effects.ConclusionsThe study provides transcriptome evidence of CagA-associated intracellular regulation during H. pylori infection, demonstrating that CagAE exerts stronger effects on intracellular signaling than CagAW. These findings offer insights into the heightened carcinogenic potential of CagAE in H. pylori-induced gastric cancer.

Project description:BackgroundHighly virulent strains of the gastric pathogen Helicobacter pylori encode a type IV secretion system (T4SS) that delivers the effector protein CagA into gastric epithelial cells. Translocated CagA undergoes tyrosine phosphorylation by members of the oncogenic c-Src and c-Abl host kinases at EPIYA-sequence motifs A, B and D in East Asian-type strains. These phosphorylated EPIYA-motifs serve as recognition sites for various SH2-domains containing human proteins, mediating interactions of CagA with host signaling factors to manipulate signal transduction pathways. Recognition of phospho-CagA is mainly based on the use of commercial pan-phosphotyrosine antibodies that were originally designed to detect phosphotyrosines in mammalian proteins. Specific anti-phospho-EPIYA antibodies for each of the three sites in CagA are not forthcoming.ResultsThis study was designed to systematically analyze the detection preferences of each phosphorylated East Asian CagA EPIYA-motif by pan-phosphotyrosine antibodies and to determine a minimal recognition sequence. We synthesized phospho- and non-phosphopeptides derived from each predominant EPIYA-site, and determined the recognition patterns by seven different pan-phosphotyrosine antibodies using Western blotting, and also investigated representative East Asian H. pylori isolates during infection. The results indicate that a total of only 9-11 amino acids containing the phosphorylated East Asian EPIYA-types are required and sufficient to detect the phosphopeptides with high specificity. However, the sequence recognition by the different antibodies was found to bear high variability. From the seven antibodies used, only four recognized all three phosphorylated EPIYA-motifs A, B and D similarly well. Two of the phosphotyrosine antibodies preferentially bound primarily to the phosphorylated motif A and D, while the seventh antibody failed to react with any of the phosphorylated EPIYA-motifs. Control experiments confirmed that none of the antibodies reacted with non-phospho-CagA peptides and in accordance were able to recognize phosphotyrosine proteins in human cells.ConclusionsThe results of this study disclose the various binding preferences of commercial anti-phosphotyrosine antibodies for phospho-EPIYA-motifs, and are valuable in the application for further characterization of CagA phosphorylation events during infection with H. pylori and risk prediction for gastric disease development.

Dataset Information

Characterization of a novel Helicobacter pylori East Asian-type CagA ELISA for detecting patients infected with various cagA genotypes.

Publications

Characterization of a novel Helicobacter pylori East Asian-type CagA ELISA for detecting patients infected with various cagA genotypes.

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