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1.
Gut ; 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31857433

RESUMO

OBJECTIVE: Gastrointestinal microbiota may be involved in Helicobacter pylori-associated gastric cancer development. The aim of this study was to explore the possible microbial mechanisms in gastric carcinogenesis and potential dysbiosis arising from H. pylori infection. DESIGN: Deep sequencing of the microbial 16S ribosomal RNA gene was used to investigate alterations in paired gastric biopsies and stool samples in 58 subjects with successful and 57 subjects with failed anti-H. pylori treatment, relative to 49 H . pylori negative subjects. RESULTS: In H. pylori positive subjects, richness and Shannon indexes increased significantly (both p<0.001) after successful eradication and showed no difference to those of negative subjects (p=0.493 for richness and p=0.420 for Shannon index). Differential taxa analysis identified 18 significantly altered gastric genera after eradication. The combination of these genera into a Microbial Dysbiosis Index revealed that the dysbiotic microbiota in H. pylori positive mucosa was associated with advanced gastric lesions (chronic atrophic gastritis and intestinal metaplasia/dysplasia) and could be reversed by eradication. Strong coexcluding interactions between Helicobacter and Fusobacterium, Neisseria, Prevotella, Veillonella, Rothia were found only in advanced gastric lesion patients, and were absent in normal/superficial gastritis group. Changes in faecal microbiota included increased Bifidobacterium after successful H. pylori eradication and more upregulated drug-resistant functional orthologs after failed treatment. CONCLUSION: H. pylori infection contributes significantly to gastric microbial dysbiosis that may be involved in carcinogenesis. Successful H. pylori eradication potentially restores gastric microbiota to a similar status as found in uninfected individuals, and shows beneficial effects on gut microbiota.

2.
Sci Rep ; 9(1): 17401, 2019 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-31758014

RESUMO

Vaccination is the most effective method to prevent infectious diseases. However, approaches to identify novel vaccine candidates are commonly laborious and protracted. While surface proteins are suitable vaccine candidates and can elicit antibacterial antibody responses, systematic approaches to define surfomes from gram-negatives have rarely been successful. Here we developed a combined discovery-driven mass spectrometry and computational strategy to identify bacterial vaccine candidates and validate their immunogenicity using a highly prevalent gram-negative pathogen, Helicobacter pylori, as a model organism. We efficiently isolated surface antigens by enzymatic cleavage, with a design of experiment based strategy to experimentally dissect cell surface-exposed from cytosolic proteins. From a total of 1,153 quantified bacterial proteins, we thereby identified 72 surface exposed antigens and further prioritized candidates by computational homology inference within and across species. We next tested candidate-specific immune responses. All candidates were recognized in sera from infected patients, and readily induced antibody responses after vaccination of mice. The candidate jhp_0775 induced specific B and T cell responses and significantly reduced colonization levels in mouse therapeutic vaccination studies. In infected humans, we further show that jhp_0775 is immunogenic and activates IFNγ secretion from peripheral CD4+ and CD8+ T cells. Our strategy provides a generic preclinical screening, selection and validation process for novel vaccine candidates against gram-negative bacteria, which could be employed to other gram-negative pathogens.

3.
Braz J Microbiol ; 2019 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-31656022

RESUMO

Noroviruses (NoV) cause the majority of non-bacterial gastroenteritis cases worldwide, with genotype II.4 being the most common. The aim of our study was to quantitate norovirus-specific IgG in immunocompromised patients before and after laboratory-confirmed norovirus infection. A quantitative ELISA was developed by coating ELISA plates with recombinantly expressed P domain of GII.1 capsid protein. After testing mouse sera drawn before and after immunization with GII.1- and GII.4 P domain, sera from GII.1- and GII.4 infected patients were tested. The assay reliably detected preexisting NoV-specific IgG antibodies. Sera drawn after infection showed increased antibody concentrations. Antibodies elicited by GII.1- and GII.4 infections could be detected with coated GII.1 capsid protein. IgG levels remained constant during the first week and then increased in the second week after laboratory diagnosis. The results show that immunocompromised patients elicited IgG responses to NoV infections that could be reliably detected with our quantitative ELISA.

4.
J Immunol ; 203(8): 2183-2193, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31511355

RESUMO

Helicobacter pylori colonizes the stomach of around 50% of humans. This chronic infection can lead to gastric pathologic conditions such as gastric ulcers and gastric adenocarcinomas. The strong inflammatory response elicited by H. pylori is characterized by the induction of the expression of several cytokines. Among those, IL-18 is found highly upregulated in infected individuals, and its expression correlates with the severity of gastric inflammation. IL-18 is produced as inactive proform and has to be cleaved by the multiprotein complex inflammasome to be active. In immune cells, the NLRC4 inflammasome, which is activated by flagellin or bacterial secretion systems, was shown to be dispensable for H. pylori-induced inflammasome activation. However, apart from immune cells, gastric epithelial cells can also produce IL-18. In this study, we analyzed the role of the NLRC4 inflammasome during H. pylori infection. Our results indicate that NLRC4 and a functional type IV secretion system are crucial for the production of IL-18 from human and murine gastric epithelial cells. In vivo, Nlrc4-/- mice failed to produce gastric IL-18 upon H. pylori infection. Compared with wild type mice, Nlrc4-/- mice controlled H. pylori better without showing strong inflammation. Moreover, H. pylori-induced IL-18 inhibits ß-defensin 1 expression in a NF-κB-dependent manner, resulting in higher bacterial colonization. At the same time, inflammasome activation enhances neutrophil infiltration, resulting in inflammation. Thus, NLRC4 inflammasome activation and subsequent IL-18 production favors bacterial persistence by inhibiting antimicrobial peptide production and, at the same time, contributes to gastric inflammation.

5.
Cell Rep ; 28(1): 231-244.e5, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31269443

RESUMO

Helicobacter pylori chronically colonizes the stomach and is strongly associated with gastric cancer. Its concomitant occurrence with helminths such as schistosomes has been linked to reduced cancer incidence, presumably due to suppression of H. pylori-associated pro-inflammatory responses. However, experimental evidence in support of such a causal link or the mutual interaction of both pathogens is lacking. We investigated the effects of co-infection during the different immune phases of S. mansoni infection. Surprisingly, co-infected mice had increased H. pylori gastric colonization during the interferon gamma (IFNγ) phase of schistosome infection but reduced infiltration of T cells in the stomach due to misdirection of antigen-experienced CXCR3+ T cells to the liver. Unexpectedly, H. pylori co-infection resulted in partial protection from schistosome-induced liver damage. Here, we demonstrate that an increase in fibrosis-protective IL-13Ra2 is associated with H. pylori infection. Thus, our study strongly points to an immunological interaction of anatomically isolated pathogens, eventually resulting in altered disease pathology.

6.
Sci Rep ; 9(1): 7030, 2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31065023

RESUMO

Helicobacter pylori infection induces a number of pro-inflammatory signaling pathways contributing to gastric inflammation and carcinogenesis. Among those, NF-κB signaling plays a pivotal role during infection and malignant transformation of the gastric epithelium. However, deficiency of the adaptor molecule myeloid differentiation primary response 88 (MyD88), which signals through NF-κB, led to an accelerated development of gastric pathology upon H. felis infection, but the mechanisms leading to this phenotype remained elusive. Non-canonical NF-κB signaling was shown to aggravate H. pylori-induced gastric inflammation via activation of the lymphotoxin ß receptor (LTßR). In the present study, we explored whether the exacerbated pathology observed in MyD88-deficient (Myd88-/-) mice was associated with aberrant activation of non-canonical NF-κB. Our results indicate that, in the absence of MyD88, H. felis infection enhances the activation of non-canonical NF-κB that is associated with increase in Cxcl9 and Icam1 gene expression and CD3+ lymphocyte recruitment. In addition, activation of signal transducer and activator of transcription 3 (STAT3) signaling was higher in Myd88-/- compared to wild type (WT) mice, indicating a link between MyD88 deficiency and STAT3 activation in response to H. felis infection. Thereby, MyD88 deficiency results in accelerated and aggravated gastric pathology induced by Helicobacter through activation of non-canonical NF-κB.

7.
Oncoimmunology ; 8(4): e1553487, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30906650

RESUMO

We previously showed that the colorectal cancer colonizing bacterium Fusobacterium nucleatum protects tumors from immune cell attack via binding of the fusbacterial Fap2 outer-membrane protein to TIGIT, a checkpoint inhibitory receptor expressed on T cells and NK cells. Helicobacter pylori, the causative agent for peptic ulcer disease, is associated with the development of gastric adenocarcinoma and MALT lymphoma. The HopQ outer-membrane adhesin of H. pylori was recently shown to bind carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) including CEACAM1, an inhibitory receptor expressed mainly by activated T and NK cells. Here we investigated the possibility that similar to Fap2, HopQ can also inhibit immune cell activities by interacting with CEACAM1. We used several approaches to confirm that HopQ indeed interacts with CEACAM1, and show that CEACAM1-mediated activation by HopQ, may inhibit NK and T cell functions.

8.
Cancers (Basel) ; 11(3)2019 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-30884828

RESUMO

The E3 ubiquitin ligase ring finger protein 43 (RNF43) is frequently mutated in gastric tumors and loss of RNF43 expression was suggested to be one of the key events during the transition from adenoma to gastric carcinoma. Functional studies on RNF43 have shown that it acts as a tumor suppressor by negatively regulating Wnt signaling. Interestingly, we observed that RNF43H292R/H295R mice bearing two point mutations in the ring domain displayed thickening of the mucosa at early age but did not develop neoplasia. In this study, we infected these mice for 6 months with Helicobacter pylori, which has been described as one of the major risk factors for gastric cancer. Mice bearing mutant RNF43H292R/H295R showed higher gastritis scores upon H. pylori infection compared to wild-type mice, accompanied by increased lymphocyte infiltration and Ifng levels. Furthermore, infected Rnf43 mutant mice developed atrophy, hyperplasia and MUC2 expressing metaplasia and displayed higher levels of the gastric stem cell marker CD44 and canonical NF-κB signaling. In summary, our results show that transactivating mutations in the tumor suppressor Rnf43 can worsen H. pylori induced pathology.

9.
Carcinogenesis ; 40(4): 551-559, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-30380024

RESUMO

Ring finger protein 43 (RNF43) is an E3 ubiquitin ligase that has been described to be frequently mutated in gastrointestinal cancers. RNF43 downregulation was associated with distant metastasis, TNM stage and poorer survival in patients with gastric and colorectal cancers. Functional analysis has shown that overexpressed RNF43 negatively regulates Wnt signalling by ubiquitinating Frizzled receptors and targeting them for degradation and by sequestering T-cell factor 4 (TCF4) to the nuclear membrane, thereby inhibiting Wnt-mediated transcription. In the stomach, RNF43 overexpression was shown to impair stem-like properties and to be negatively correlated with expression of Wnt-target genes. In this study, we show that RNF43 knockdown enhances the tumourigenic potential of gastric and colorectal cancer cell lines in vitro and in vivo. Thus, loss of RNF43 leads to increased proliferation and anchorage-independent growth as well as increased invasive capacity. In a xenograft model, RNF43 depletion enhanced tumour growth. Furthermore, we established two mouse models in which mutations in the RING domain of RNF43 were introduced. In the intestine and colon, loss of Rnf43 did not induce changes in epithelial architecture or proliferation. In contrast, in the stomach, thickening of the mucosa, hyperplasia and cellular atypia were observed in these mice. Notably, this was independent of elevated Wnt signalling. Together, our results show that RNF43 plays a tumour suppressive role in gastric and colorectal cancer cells and that the loss of its function alters gastric tissue homeostasis in vivo.

10.
Artigo em Inglês | MEDLINE | ID: mdl-29971220

RESUMO

Eradication of Helicobacter pylori has been found to be effective for gastric cancer prevention, but uncertainties remain about the possible adverse consequences such as the potential microbial dysbiosis. In our study, we investigated the association between gut microbiota and H. pylori-related gastric lesions in 47 subjects by deep sequencing of microbial 16S ribosomal RNA (rRNA) gene in fecal samples. The dominant phyla in fecal samples were Bacteroidetes, Firmicutes, and Proteobacteria with average relative abundances of 54.77, 31.37 and 12.91%, respectively. Microbial diversity analysis showed that observed species and Shannon index were increased in subjects with past or current H. pylori infection compared with negative subjects. As for the differential bacteria, the average relative abundance of Bacteroidetes was found to significantly decrease from H. pylori negative (66.16%) to past infection group (33.01%, p = 0.007), as well as from normal (76.49%) to gastritis (56.04%) and metaplasia subjects (46.83%, p = 0.027). For Firmicutes and Proteobacteria, the average relative abundances showed elevated trends in the past H. pylori infection group (47.11, 20.53%) compared to negative group (23.44, 9.05%, p = 0.068 and 0.246, respectively), and similar increased trends were also found from normal (18.23, 5.05%) to gastritis (35.31, 7.23%, p = 0.016 and 0.294, respectively) or metaplasia subjects (32.33, 20.07%, both p < 0.05). These findings suggest that the alterations of fecal microbiota, especially the dominant phyla of Bacteroidetes, Firmicutes and Proteobacteria, may be involved in the process of H. pylori-related gastric lesion progression and provide hints for future evaluation of microbial changes after H. pylori eradication.


Assuntos
DNA Bacteriano/genética , Microbioma Gastrointestinal/genética , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Neoplasias Gástricas/microbiologia , Adulto , Idoso , Disbiose/microbiologia , Disbiose/patologia , Fezes/microbiologia , Feminino , Mucosa Gástrica/microbiologia , Mucosa Gástrica/patologia , Gastrite/microbiologia , Gastrite/patologia , Infecções por Helicobacter/diagnóstico , Humanos , Masculino , Metaplasia/microbiologia , Metaplasia/patologia , Pessoa de Meia-Idade , Neoplasias Gástricas/patologia
11.
EMBO J ; 37(13)2018 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-29858229

RESUMO

The human gastric pathogen Helicobacter pylori is a major causative agent of gastritis, peptic ulcer disease, and gastric cancer. As part of its adhesive lifestyle, the bacterium targets members of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family by the conserved outer membrane adhesin HopQ. The HopQ-CEACAM1 interaction is associated with inflammatory responses and enables the intracellular delivery and phosphorylation of the CagA oncoprotein via a yet unknown mechanism. Here, we generated crystal structures of HopQ isotypes I and II bound to the N-terminal domain of human CEACAM1 (C1ND) and elucidated the structural basis of H. pylori specificity toward human CEACAM receptors. Both HopQ alleles target the ß-strands G, F, and C of C1ND, which form the trans dimerization interface in homo- and heterophilic CEACAM interactions. Using SAXS, we show that the HopQ ectodomain is sufficient to induce C1ND monomerization and thus providing H. pylori a route to influence CEACAM-mediated cell adherence and signaling events.


Assuntos
Antígenos CD/fisiologia , Proteínas de Bactérias/fisiologia , Moléculas de Adesão Celular/fisiologia , Helicobacter pylori/fisiologia , Animais , Antígenos CD/química , Proteínas de Bactérias/química , Células CHO , Moléculas de Adesão Celular/química , Linhagem Celular Tumoral , Cricetulus , Humanos , Multimerização Proteica
12.
PLoS One ; 13(5): e0196977, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29738579

RESUMO

BACKGROUND: Clostridium difficile infection (CDI) is a major cause of hospital-acquired diarrhea. Secondary bile acids were shown to confer resistance to colonization by C. difficile. 7α-dehydroxylation is a key step in transformation of primary to secondary bile acids and required genes have been located in a single bile acid-inducible (bai) operon in C. scindens as well as in C. hiranonis, two Clostridium sp. recently reported to protect against C. difficile colonization. AIM: To analyze baiCD gene abundance in C. difficile positive and negative fecal samples. MATERIAL & METHODS: A species-specific qPCR for detecting baiCD genes was established. Fecal samples of patients with CDI, asymptomatic toxigenic C. difficile colonization (TCD), non-toxigenic C. difficile colonization (NTCD), of C. difficile negative (NC) patients, and of two patients before and after fecal microbiota transplantation (FMT) for recurrent CDI (rCDI) were tested for the presence of the baiCD genes. RESULTS: The prevalence of the baiCD gene cluster was significantly higher in C. difficile negative fecal samples than in samples of patients diagnosed with CDI (72.5% (100/138) vs. 35.9% (23/64; p<0.0001). No differences in baiCD gene cluster prevalence were seen between NC and NTCD or NC and TCD samples. Both rCDI patients were baiCD-negative at baseline, but one of the two patients turned positive after successful FMT from a baiCD-positive donor. CONCLUSION: Fecal samples of CDI patients are less frequently baiCD-positive than samples from asymptomatic carriers or C. difficile-negative individuals. Furthermore, we present a case of baiCD positivity observed after successful FMT for rCDI.


Assuntos
Proteínas de Bactérias/genética , Ácidos e Sais Biliares/genética , Infecções por Clostridium/genética , Clostridium difficile/genética , Diarreia/genética , Antibacterianos/uso terapêutico , Toxinas Bacterianas , Bile/microbiologia , Ácidos e Sais Biliares/biossíntese , Infecções por Clostridium/microbiologia , Infecções por Clostridium/transmissão , Clostridium difficile/patogenicidade , Diarreia/microbiologia , Transplante de Microbiota Fecal , Fezes/microbiologia , Feminino , Humanos , Masculino , Microbiota/genética
13.
Nat Protoc ; 13(5): 1153-1180, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29700486

RESUMO

Aptamers are single-stranded oligonucleotides that are in vitro-selected to recognize their target molecule with high affinity and specificity. As they consist of the four canonical nucleobases, their chemical diversity is limited, which in turn limits the addressable target spectrum. Introducing chemical modifications into nucleic acid libraries increases the interaction capabilities of the DNA and thereby the target spectrum. Here, we describe a protocol to select nucleobase-modified aptamers by using click chemistry (CuAAC) to introduce the preferred chemical modification. The use of click chemistry to modify the DNA library enables the introduction of a wide range of possible functionalities, which can be customized to the requirements of the target molecule and the desired application. This protocol yields modified DNA aptamers with extended interaction properties that are not accessible with the canonical set of nucleotides. After synthesis of the starting library containing a commercially available, alkyne-modified uridine (5-ethynyl-deoxyuridine (EdU)) instead of thymidine, the library is functionalized with the modification of choice by CuAAC. The thus-modified DNA is incubated with the target molecule and the best binding sequences are recovered. The chemical modification is removed during the amplification process. Therefore, this protocol is compatible with conventional amplification procedures and avoids enzymatic incompatibility problems associated with more extensive nucleobase modifications. After single-strand generation, the modification is reintroduced into the enriched library, which can then be subjected to the subsequent selection cycle. The duration of each selection cycle as outlined in the protocol is ∼1 d.


Assuntos
Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/metabolismo , Química Click/métodos , DNA/metabolismo , Técnica de Seleção de Aptâmeros/métodos , Aptâmeros de Nucleotídeos/isolamento & purificação , Técnicas de Amplificação de Ácido Nucleico , Hibridização de Ácido Nucleico
15.
Sci Rep ; 7(1): 13636, 2017 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-29057967

RESUMO

Helicobacter pylori γ-glutamyl transferase (gGT) is a key bacterial virulence factor that is not only important for bacterial gastric colonization but also related to the development of gastric pathology. Despite accumulating evidence for pathogenic and immunologic functions of H. pylori gGT, it is still unclear how it supports gastric colonization and how its specific effects on the host's innate and adaptive immune responses contribute to colonization and pathology. We have compared mice showing similar bacterial load after infection with gGT-proficient or gGT-deficient H. pylori to analyse the specific role of the enzyme during infection. Our data indicate that H. pylori gGT supports initial colonization. Nevertheless, bacteria lacking gGT can still colonize and persist. We observed that the presence of gGT during infection favoured a proinflammatory innate and adaptive immune response. Notably, H. pylori gGT activity was linked to increased levels of IFNγ, which were attributed to a differential recruitment of CD8+ T cells to the stomach. Our data support an essential role for H. pylori gGT in gastric colonization and further suggest that gGT favours infiltration of CD8+ cells to the gastric mucosa, which might play an important and yet overlooked role in the pathogenesis of H. pylori.


Assuntos
Proteínas de Bactérias/metabolismo , Linfócitos T CD8-Positivos/imunologia , Infecções por Helicobacter/imunologia , Helicobacter pylori/enzimologia , Fatores de Virulência/metabolismo , gama-Glutamiltransferase/metabolismo , Imunidade Adaptativa , Animais , Linfócitos T CD8-Positivos/enzimologia , Linfócitos T CD8-Positivos/microbiologia , Modelos Animais de Doenças , Feminino , Infecções por Helicobacter/enzimologia , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/patologia , Helicobacter pylori/crescimento & desenvolvimento , Imunidade Inata , Interferon gama/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estômago/enzimologia , Estômago/imunologia , Estômago/microbiologia , Estômago/patologia
16.
Proteomes ; 5(4)2017 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-28972560

RESUMO

Infection with Helicobacter pylori (H. pylori) occurs in 50% of the world population, and is associated with the development of ulcer and gastric cancer. Serological diagnostic tests indicate an H. pylori infection by detecting antibodies directed against H. pylori proteins. In addition to line blots, multiplex assay platforms provide smart solutions for the simultaneous analysis of antibody responses towards several H. pylori proteins. We used seven H. pylori proteins (FliD, gGT, GroEL, HpaA, CagA, VacA, and HP0231) and an H. pylori lysate for the development of a multiplex serological assay on a novel microfluidic platform. The reaction limited binding regime in the microfluidic channels allows for a short incubation time of 35 min. The developed assay showed very high sensitivity (99%) and specificity (100%). Besides sensitivity and specificity, the technical validation (intra-assay CV = 3.7 ± 1.2% and inter-assay CV = 5.5 ± 1.2%) demonstrates that our assay is also a robust tool for the analysis of the H. pylori-specific antibody response. The integration of the virulence factors CagA and VacA allow for the assessment of the risk for gastric cancer development. The short assay time and the performance of the platform shows the potential for implementation of such assays in a clinical setting.

17.
J Immunol Res ; 2017: 8394593, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28638837

RESUMO

Helicobacter pylori infection shows a worldwide prevalence of around 50%. However, only a minority of infected individuals develop clinical symptoms or diseases. The presence of H. pylori virulence factors, such as CagA and VacA, has been associated with disease development, but assessment of virulence factor presence requires gastric biopsies. Here, we evaluate the H. pylori recomLine test for risk stratification of infected patients by comparing the test score and immune recognition of type I or type II strains defined by the virulence factors CagA, VacA, GroEL, UreA, HcpC, and gGT with patient's disease status according to histology. Moreover, the immune responses of eradicated individuals from two different populations were analysed. Their immune response frequencies and intensities against all antigens except CagA declined below the detection limit. CagA was particularly long lasting in both independent populations. An isolated CagA band often represents past eradication with a likelihood of 88.7%. In addition, a high recomLine score was significantly associated with high-grade gastritis, atrophy, intestinal metaplasia, and gastric cancer. Thus, the recomLine is a sensitive and specific noninvasive test for detecting serum responses against H. pylori in actively infected and eradicated individuals. Moreover, it allows stratifying patients according to their disease state.


Assuntos
Gastrite/imunologia , Gastrite/microbiologia , Infecções por Helicobacter/imunologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/patogenicidade , Imunoensaio/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos de Bactérias/imunologia , Antígenos de Bactérias/isolamento & purificação , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/isolamento & purificação , Biópsia , Feminino , Gastrite/sangue , Gastrite/diagnóstico , Infecções por Helicobacter/complicações , Infecções por Helicobacter/diagnóstico , Helicobacter pylori/classificação , Helicobacter pylori/imunologia , Helicobacter pylori/isolamento & purificação , Humanos , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Testes Sorológicos/métodos , Estômago/microbiologia , Estômago/patologia , Neoplasias Gástricas/etiologia , Neoplasias Gástricas/microbiologia , Fatores de Virulência/sangue , Adulto Jovem
18.
Sci Rep ; 7(1): 2072, 2017 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-28522798

RESUMO

The performance of diagnostic tests in intervention trials of Helicobacter pylori (H.pylori) eradication is crucial, since even minor inaccuracies can have major impact. To determine the cut-off point for 13C-urea breath test (13C-UBT) and to assess if it can be further optimized by serologic testing, mathematic modeling, histopathology and serologic validation were applied. A finite mixture model (FMM) was developed in 21,857 subjects, and an independent validation by modified Giemsa staining was conducted in 300 selected subjects. H.pylori status was determined using recomLine H.pylori assay in 2,113 subjects with a borderline 13C-UBT results. The delta over baseline-value (DOB) of 3.8 was an optimal cut-off point by a FMM in modelling dataset, which was further validated as the most appropriate cut-off point by Giemsa staining (sensitivity = 94.53%, specificity = 92.93%). In the borderline population, 1,468 subjects were determined as H.pylori positive by recomLine (69.5%). A significant correlation between the number of positive H.pylori serum responses and DOB value was found (rs = 0.217, P < 0.001). A mathematical approach such as FMM might be an alternative measure in optimizing the cut-off point for 13C-UBT in community-based studies, and a second method to determine H.pylori status for subjects with borderline value of 13C-UBT was necessary and recommended.


Assuntos
Algoritmos , Testes Respiratórios/métodos , Infecções por Helicobacter/diagnóstico , Técnicas de Diagnóstico Molecular/normas , Neoplasias Gástricas/diagnóstico , Adulto , Isótopos de Carbono , Ensaios Clínicos como Assunto , Feminino , Humanos , Limite de Detecção , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Neoplasias Gástricas/microbiologia , Ureia
19.
Curr Top Microbiol Immunol ; 400: 53-71, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28124149

RESUMO

Helicobacter pylori infection is commonly acquired during childhood, can persist lifelong if not treated, and can cause different gastric pathologies, including chronic gastritis, peptic ulcer disease, and eventually gastric cancer. H. pylori has developed a number of strategies in order to cope with the hostile conditions found in the human stomach as well as successful mechanisms to evade the strong innate and adaptive immune responses elicited upon infection. Thus, by manipulating innate immune receptors and related signaling pathways, inducing tolerogenic dendritic cells and inhibiting effector T cell responses, H. pylori ensures low recognition by the host immune system as well as its persistence in the gastric epithelium. Bacterial virulence factors such as cytotoxin-associated gene A, vacuolating cytotoxin A, or gamma-glutamyltranspeptidase have been extensively studied in the context of bacterial immune escape and persistence. Further, the bacterium possesses other factors that contribute to immune evasion. In this chapter, we discuss in detail the main evasion and persistence strategies evolved by the bacterium as well as the specific bacterial virulence factors involved.


Assuntos
Infecções por Helicobacter/imunologia , Helicobacter pylori/imunologia , Evasão da Resposta Imune , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Mucosa Gástrica/imunologia , Mucosa Gástrica/microbiologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Helicobacter pylori/fisiologia , Humanos , Fatores de Virulência/genética , Fatores de Virulência/imunologia
20.
High Throughput ; 6(4)2017 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-29855458

RESUMO

The spread of infectious diseases and vaccination history are common subjects of epidemiological and immunological research studies. Multiplexed serological assays are useful tools for assessing both current and previous infections as well as vaccination efficacy. We developed a serological multi-pathogen assay for hepatitis A, B and C virus, cytomegalovirus (CMV), Toxoplasma gondii, and Helicobacter pylori using a bead-based multiplex assay format. The multi-pathogen assay consisting of 15 antigens was utilized for the analysis of the serological response in elderly individuals of an influenza vaccination study (n = 34). The technical assay validation revealed a mean intra-assay precision of coefficient of variation (CV) = 3.2 ± 1.5% and a mean inter-assay precision of CV = 8.2 ± 5.3% across all 15 antigens and all tested samples, indicating a robust test system. Furthermore, the assay shows high sensitivities (ranging between 94% and 100%) and specificities (ranging between 93% and 100%) for the different pathogens. The highest seroprevalence rates in our cohort were observed for hepatitis A virus (HAV; 73.5%), followed by CMV (70.6%), T. gondii (67.6%) and H. pylori (32.4%). Seroprevalences for hepatitis B virus (HBV, 8.8%) and hepatitis C virus (HCV, 0%) were low. The seroprevalences observed in our study were similar to those from other population-based studies in Germany. In summary, we conclude that our multiplex serological assay represents a suitable tool for epidemiological studies.

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