New Serological Assay for Detection of Putative
            <i>Helicobacter pylori</i>
            Virulence Factors

Park, Chang-Young; Cho, Yong-Kyun; Kodama, Tadashi; El‐Zimaity, Hala; Osato, Michael S.; Graham, David Y.; Yamaoka, Yoshio

doi:10.1128/jcm.40.12.4753-4756.2002

Cited by 30 publications

(40 citation statements)

References 9 publications

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“…Helico Blot 2.1 TM kits reportedly have high sensitivity (99% for both H. pylori and CagA seropositivity) and specificity (98% for H. pylori and 90% for CagA seropositivity) among the Korean population. 13 …”

Section: Epidemiologymentioning

confidence: 99%

Soluble c‐Met protein as a susceptible biomarker for gastric cancer risk: A nested case‐control study within the Korean Multicenter Cancer Cohort

Yang¹,

Yang²,

Kim³

et al. 2012

Intl Journal of Cancer

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This study was conducted to evaluate the relevance of the soluble form of c-Met protein, a truncated form of the c-Met membrane receptor involved in the CagA pathway, as a potential biomarker for gastric cancer. Among 290 gastric cancer case-control sets selected from the Korean Multicenter Cancer Cohort, the plasma concentrations of soluble c-Met protein were measured with enzyme-linked immunosorbent assays. Using analysis of variance and covariance models with age, sex, smoking, Helicobacter pylori infection, and CagA seropositivity, the mean concentrations of soluble c-Met protein between cases and controls were compared. To evaluate the association between gastric cancer and a c-Met protein level, odds ratios and 95% confidence intervals were estimated using conditional logistic regression models. Interactions between CagA-related genes and the soluble c-Met protein concentration were also investigated. The overall median plasma concentration of soluble c-Met among cases was significantly lower than those of controls (1.390 vs. 1.610 ng/mL, p < 0.0001). Closer to the onset of gastric cancer, the soluble c-Met protein level decreased linearly in a time-dependent manner (p for trend 5 0.0002). The combined effects between the CagA-related genes and the soluble c-Met protein concentration significantly intensified risks for gastric cancer. Restricted analyses including cases that had been diagnosed within 1 year after entering the cohort had a fair degree of ability (area under the receiver operating characteristic curve of 0.73-0.77) to discriminate gastric cancer cases from normal controls. Our findings demonstrate the potential of the soluble form of c-Met protein as a novel biomarker for gastric cancer. The beneficial effects of a high soluble c-Met concentration in human plasma are strongly supported.

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Section: Epidemiologymentioning

confidence: 99%

Soluble c‐Met protein as a susceptible biomarker for gastric cancer risk: A nested case‐control study within the Korean Multicenter Cancer Cohort

Yang¹,

Yang²,

Kim³

et al. 2012

Intl Journal of Cancer

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“…On the other hand, there were no false positive results and therefore the Western-rCagA showed 100% specificity. This is also a good result for the rCagA of this study because the lack of specificity of antiCagA tests has been attributed in part to differences in the CagA antigens used (12,30).…”

Section: Discussionmentioning

confidence: 56%

Clonaje y expresión de un fragmento recombinante del gen cagA de Helicobacter pylori y su evaluación preliminar en el serodiagnóstico

et al. 2013

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Introduction:Helicobacter pylori strains expressing cytotoxic CagA protein are more commonly associated with peptic ulceration, atrophic gastritis and gastric adenocarcinoma than those lacking CagA. Determination of anti-CagA antibodies, therefore, acquires a relevant clinical significance in the serological detection of H. pylori infection and disease risk prediction. However, the CagA-serology has been questioned due to the differences found in their performance evaluations in different populations. Objective: To obtain a recombinant CagA fragment useful for serodiagnosis of H. pylori infection Methods: A fragment of the cagA gene was cloned into a prokaryotic T7 RNA polymerase expression vector. A recombinant C-terminal His 6 -tagged CagA was expressed, subsequently solubilized with urea and purified by immobilized metal affinity chromatography. The performance of the recombinant protein was evaluated using 180 human serum samples with an in-house Western blot assay compared to the Helicoblot 2.1 reference test. Results: The expressed His 6 -tagged CagA showed an immunoreactive 80kDa band as was revealed by SDS-PAGE and Western blot analysis using two different specific anti-CagA polyclonal antibodies. The recombinant protein was successfully purified obtaining a 93% of purity. The performance analysis of the purified recombinant antigen showed good immunoreactivity and exhibited values of sensitivity, specificity and accuracy of 88.1%, 100% and 92.7%, respectively. Conclusion: The CagA fragment of the study may constitute a useful tool for serological diagnosis of CagA-positive H. pylori infection. Clonación y expresión de un fragmento recombinante del gen cagA de Helicobacter pylori y su evaluación preliminar en el serodiagnóstico Introducción. Las cepas de Helicobacter pylori que expresan la citotoxina CagA, se asocian más frecuentemente con úlcera péptica, gastritis atrófica y adenocarcinoma gástrico que las que carecen de esta citotoxina. Por lo anterior, el determinar la presencia de anticuerpos anti-CagA adquiere gran importancia clínica en la detección serológica de la infección por H. pylori y la predicción del riesgo de enfermedades. Sin embargo, los métodos serológicos que emplean CagA han sido cuestionados debido a las diferencias encontradas en las evaluaciones de su desempeño en diversas poblaciones. Objetivo. Obtener un fragmento recombinante de la proteína CagA para el serodiagnóstico de la infección por H. pylori. Materiales y métodos. Un fragmento del gen cagA fue clonado en un vector de expresión procariota que contenía el promotor de la T7 ARN polimerasa. El fragmento de la proteína CagA con seis histidinas en la región C-terminal, se expresó, se solubilizó con urea y se purificó por cromatografía de afinidad con iones metálicos inmovilizados. El desempeño de la proteína recombinante se evaluó empleando un método in house de Western Blot y 180 sueros humanos. Los resultados se compararon con la prueba de referencia Helicoblot 2.1. 547 Biomédica 2013;33:546-53 Recombinant CagA fragment fo...

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“…Similarly to that we have previously observed for children (Rocha et al 2000), the assay showed high sensitivity (92.8%) for the diagnosis of the infection in adults. Other authors, employing the same kit (Yamaoka et al 1998, Malaty et al 2002, Park et al 2002 or in-house techniques (Faulde et al 1993, Klaamas et al 1996, Karvar et al 1997, Nilsson et al 1997, Holtmann et al 1998) also reported high sensitivity for the test. In addition, we observed that the sensitivity was similar in patients with duodenal ulcer, gastric carcinoma, and gastritis only.…”

Section: Discussionmentioning

confidence: 99%

“…The presence of antibodies against H. pylori antigens can be evaluated by immunoblotting (Mitchell et al 1996, Aucher et al 1998, Yamaoka et al 1998, Figueiredo et al 2001, Park et al 2002. Although expensive and time-consuming, the test seems to be more sensitive than ELISA, especially when the levels of antibodies are low.…”

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confidence: 99%

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Immunoblotting for the serodiagnosis of Helicobacter pylori infection in Brazilian patients with and without gastric carcinoma

Rocha

Leite

et al. 2004

Mem. Inst. Oswaldo Cruz

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New Serological Assay for Detection of Putative Helicobacter pylori Virulence Factors

Cited by 30 publications

References 9 publications

Soluble c‐Met protein as a susceptible biomarker for gastric cancer risk: A nested case‐control study within the Korean Multicenter Cancer Cohort

Soluble c‐Met protein as a susceptible biomarker for gastric cancer risk: A nested case‐control study within the Korean Multicenter Cancer Cohort

Clonaje y expresión de un fragmento recombinante del gen cagA de Helicobacter pylori y su evaluación preliminar en el serodiagnóstico

Immunoblotting for the serodiagnosis of Helicobacter pylori infection in Brazilian patients with and without gastric carcinoma

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