Helicobacter Species Research Articles

Helicobacter saguini, a Novel Helicobacter Isolated from Cotton-Top Tamarins with Ulcerative Colitis, Has Proinflammatory Properties and Induces Typhlocolitis and Dysplasia in Gnotobiotic IL-10-/- Mice.

A urease-negative, fusiform, novel bacterium named Helicobacter saguini was isolated from the intestines and feces of cotton-top tamarins (CTTs) with chronic colitis. Helicobacter sp. was detected in 69% of feces or intestinal samples from 116 CTTs. The draft genome sequence, obtained by Illumina MiSeq sequencing, for H. saguini isolate MIT 97-6194-5, consisting of ∼2.9 Mb with a G+C content of 35% and 2,704 genes, was annotated using the NCBI Prokaryotic Genomes Automatic Annotation Pipeline. H. saguini contains homologous genes of known virulence factors found in other enterohepatic helicobacter species (EHS) and H. pylori These include flagellin, γ-glutamyl transpeptidase (ggt), collagenase, the secreted serine protease htrA, and components of a type VI secretion system, but the genome does not harbor genes for cytolethal distending toxin (cdt). H. saguini MIT 97-6194-5 induced significant levels of interleukin-8 (IL-8) in HT-29 cell culture supernatants by 4 h, which increased through 24 h. mRNAs for the proinflammatory cytokines IL-1β, tumor necrosis factor alpha (TNF-α), IL-10, and IL-6 and the chemokine CXCL1 were upregulated in cocultured HT-29 cells at 4 h compared to levels in control cells. At 3 months postinfection, all H. saguini-monoassociated gnotobiotic C57BL/129 IL-10(-/-) mice were colonized and had seroconverted to H. saguini antigen with a significant Th1-associated increase in IgG2c (P < 0.0001). H. saguini induced a significant typhlocolitis, associated epithelial defects, mucosa-associated lymphoid tissue (MALT) hyperplasia, and dysplasia. Inflammatory cytokines IL-22, IL-17a, IL-1β, gamma interferon (IFN-γ), and TNF-α, as well as inducible nitric oxide synthase (iNOS) were significantly upregulated in the cecal tissues of infected mice. The expression of the DNA damage response molecule γ-H2AX was significantly higher in the ceca of H. saguini-infected gnotobiotic mice than in the controls. This model using a nonhuman primate Helicobacter sp. can be used to study the pathogenic potential of EHS isolated from primates with naturally occurring inflammatory bowel disease (IBD) and colon cancer.

Balance of Commensal Bacteria-Specific Th17 and RORγt+ Treg Cells in Intestinal Homeostasis and Inflammation

Abstract A number of Helicobacter species, including Helicobacter hepaticus, have been isolated as the etiological agents of ulcerative inflammatory bowel disease and cancer in their respective hosts. H. hepaticus induces severe Th17-Th1 mediated colitis in a number of immuno-compromised mouse strains, but does not usually cause disease in most wild-type mouse strains. However, how the inflammatory response is carefully contained to be harmless under homeostatic conditions and how perturbations lead to pathogenicity remain elusive questions. To understand this, we developed new research tools, including TCR transgenic mice, as well as MHCII tetramers to interrogate the regulation of H. hepaticus-specific CD4+ T cell function. Interestingly, in contrast to Segmented Filamentous Bacteria (SFB), which induces Th17 cells in the small intestinal lamina propria (SILP) of both IL10+/− and IL-10−/− mice, H. hepaticus mainly induces RORgt+ Treg cells in the large intestinal lamina propria (LILP) of IL-10-sufficient mice, but induces a Th17-Th1 response in the absence of IL-10. We propose that the balance between self/commensal antigen-induced RORgt+ Treg and Th17 cells may be a general strategy to control autoimmune inflammation.

An In Silico Approach for Identification of the Pathogenic Species, Helicobacter pylori and Its Relatives.

Helicobacter is an economically important genus within the phylum Proteobacteria and include many species which cause many diseases in humans. With the conventional methods, it is difficult to identify them easily due to the high genetic similarity among its species. In the present study, 361 16S rRNA (rrs) gene sequences belonging to 45 species of genus Helicobacter were analyzed. Out of these, 264 sequences of 10 clinically relevant species (including Helicobacter pylori) were used. rrs gene sequences were analyzed to obtain a phylogenetic framework tree, in silico restriction enzyme analysis and species-specific conserved motifs. Protein sequences of another housekeeping gene, hsp60 were also subjected to phylogenetic analysis to supplement the data obtained using rrs sequences. Using these approaches, six out of ten species (including H. pylori) were easily segregated, whereas four species namely H. bilis, H. cinaedi, H. felis and Candidatus H. heilmannii were found to be heterogeneous. The above approaches have also helped in segregating unclassified sequences, thus proving them as an easy diagnostic method for identifying members of genus Helicobacter up to species level.

Diagnosis of Genus Helicobacter through a hemi-nested PCR assay of 16S rRNA

The present study aimed to establish a genus-specific PCR-based assay to detect helicobacters using 16S rRNA gene as the target template. We designed the hemi-nested primers based on sequences of 16S rRNA gene of 34 types of Helicobacter species. The inclusivity, sensitivity, and specificity of the PCR assay using these primers were examined in three different models, comprising feces simulated samples, BLAB/c mice infection model and clinic patients samples. The detection sensitivity of Helicobacter pylori, Helicobacter hepaticus and Helicobacter bilis strains from feces simulated samples was all 102CFU/ml. We successfully detected H. hepaticus and H. bilis in the liver, cecum and feces of experimentally infected mice. H. pylori was successfully detected in the feces samples from 3 patients infected with H. pylori while not in the feces samples from 3 healthy human. However, the C97/C05–C97/C98 PCR assay detected H. pylori in the 2 positive samples. Due to the PCR assay’s excellent inclusivity, high sensitivity and specificity it may be used to detect the presence of Helicobacters.

Lamellipodin-Deficient Mice: A Model of Rectal Carcinoma.

During a survey of clinical rectal prolapse (RP) cases in the mouse population at MIT animal research facilities, a high incidence of RP in the lamellipodin knock-out strain, C57BL/6-Raph1tm1Fbg (Lpd-/-) was documented. Upon further investigation, the Lpd-/- colony was found to be infected with multiple endemic enterohepatic Helicobacter species (EHS). Lpd-/- mice, a transgenic mouse strain produced at MIT, have not previously shown a distinct immune phenotype and are not highly susceptible to other opportunistic infections. Predominantly male Lpd-/- mice with RP exhibited lesions consistent with invasive rectal carcinoma concomitant to clinically evident RP. Multiple inflammatory cytokines, CD11b+Gr1+ myeloid-derived suppressor cell (MDSC) populations, and epithelial cells positive for a DNA damage biomarker, H2AX, were elevated in affected tissue, supporting their role in the neoplastic process. An evaluation of Lpd-/- mice with RP compared to EHS-infected, but clinically normal (CN) Lpd-/- animals indicated that all of these mice exhibit some degree of lower bowel inflammation; however, mice with prolapses had significantly higher degree of focal lesions at the colo-rectal junction. When Helicobacter spp. infections were eliminated in Lpd-/- mice by embryo transfer rederivation, the disease phenotype was abrogated, implicating EHS as a contributing factor in the development of rectal carcinoma. Here we describe lesions in Lpd-/- male mice consistent with a focal inflammation-induced neoplastic transformation and propose this strain as a mouse model of rectal carcinoma.

Detection of Helicobacter spp. in the saliva of dogs with gastritis.

The aim of this study was to identify the species and determine the prevalence of gastric Helicobacter in the saliva of dogs with gastritis. The study was carried out on 30 dogs of different breeds, genders and ages, which were diagnosed with gastritis. The nested-PCR method was used to detect Helicobacter spp. in saliva. Helicobacter bacteria were found in the saliva samples of 23 (76.6%) dogs. Helicobacter heilmannii was the most commonly detected species of gastric Helicobacter spp. in canine saliva, and was found in 22 (73.3%) cases. The results indicate that gastric Helicobacter spp. occurs relatively frequently in dogs with gastritis. Moreover, the saliva of dogs with gastritis may be a source of Helicobacter spp. infection for humans and other animals. However, further studies are needed to confirm this finding as the PCR method does not distinguish active from inactive infections.

Alzheimer's disease and Helicobacter pylori infection: a possible link?

Alzheimer's disease (AD) is associated with Aß peptide and Tau protein deposits, but the initial process inducing the disease and ultimately neurodegeneration has not yet been elucidated. An infectious hypothesis is suggested by the alteration of the blood-brain barrier and the activation of neuroinflammation in the brain, which could play a role, especially in the decrease of Aß peptide clearance. Several viral or bacterial agents have been incriminated, including Helicobacter pylori. Infection by H. pylori is acquired during childhood and often lifetime persisting, inducing a chronic gastric inflammation, which remains asymptomatic in approximately 80% of cases. However H.pylori infection can induce systemic inflammation and increase homocysteine levels, contributing to worsen AD lesions. Association between H. pylori and AD is suggested by 1) epidemiologic studies, which show higher AD prevalence and more pronounced cognitive impairment in infected than in non-infected subjects; 2) experimental studies in murine models: a) in a first study we evaluated the impact of H.pylori infection on the brain of non-AD predisposed C57BL/6J mice. After an 18-month infection, H.pylori induced a significant gastric inflammation but no brain Aβ deposit nor increased neuroinflammation was observed in their brain; b) we currently study the impact of Helicobacter species infection on behavior and cerebral lesions of AD transgenic (APPswe/PS1dE9) mice and their wild type littermate. The results of these studies do not allow to conclude a significant association between AD and H. pylory infection but may contribute to a better understanding of the role of brain neuroinflammation in AD.

Chondroitinase AC: A host-associated genetic feature of Helicobacter bizzozeronii

Investigating mechanisms involved in host adaptation is crucial to understand pathogen evolution. Helicobacter species appear to have a host species-specific tropism, coevolving with their natural hosts, and to develop several strategies allowing the colonization of the stomach throughout lifetime of their hosts. However, little is known about genetic features associated with the adaptation to a specific animal host. In this study we discovered a polysaccharide lyase that is expressed by the canine-associated species H. bizzozeronii and acts as chondroitinase AC-type lyase of broad specificity. Except for its low pH-optimum between pH 4.0 and pH 5.5, the properties of the H. bizzozeronii chondroitin lyase AC resemble the ones from Arthrobacter aurescens. However, homologues of this gene have been detected only in Helicobacter species colonizing the canine and feline gastric mucosa. Since a unique feature of the canine stomach is the secretion of chondroitin-4-sulphate in the gastric juice of the fundus mucosa by chief cells, the expression of chondroitinase AC by H. bizzozeronii is likely the consequence of adaptation of this bacterium to its host and a potential link to gastric disorders in dogs.

Helicobacter-negative gastritis: polymerase chain reaction for Helicobacter DNA is a valuable tool to elucidate the diagnosis.

Helicobacter-negative gastritis has been increasingly reported. Molecular techniques as the polymerase chain reaction (PCR) may detect bacterial DNA in histologically negative gastritis. To evaluate of Helicobacter PCR in gastric biopsies for the daily diagnostics of Helicobacter-negative gastritis. Over a 5-year period, routine biopsies with chronic gastritis reminiscent of Helicobacter infection, but negative by histology, were tested by using a H. pylori specific PCR. Subsequently, PCR-negative samples were re-evaluated using PCR for other Helicobacter species. Of the 9184 gastric biopsies, 339 (3.7%) with histological-negative gastritis and adequate material were forwarded to PCR analysis for H. pylori and 146 (43.1%) revealed a positive result. In 193 H. pylori DNA-negative biopsies, re-analysis using PCR primers for other Helicobacter species, revealed further 23 (11.9%) positive biopsies, including 4 (2.1%) biopsies with H. heilmannii sensu lato. PCR-positive biopsies showed a higher overall inflammatory score, more lymphoid follicles/aggregates and neutrophils (P < 0.05). No Helicobacter DNA was found in control biopsies of 48 patients with neither primer set (P < 0.0001). In 274 patients with an endoscopic description, detection of H. pylori DNA was associated with ulcers and erosions (P < 0.01). Over all, in 339 histologically-negative gastric biopsies, Helicobacter DNA was detected in 169 (49.9%) samples with at least one primer set. Molecular testing offers a sensitive and specific diagnosis to a selected group of patients, in whom adequate searches for bacteria by conventional histology have resulted in the unsatisfactory diagnosis of H. pylori-negative gastritis.

A Biotin Biosynthesis Gene Restricted to Helicobacter.

In most bacteria the last step in synthesis of the pimelate moiety of biotin is cleavage of the ester bond of pimeloyl-acyl carrier protein (ACP) methyl ester. The paradigm cleavage enzyme is Escherichia coli BioH which together with the BioC methyltransferase allows synthesis of the pimelate moiety by a modified fatty acid biosynthetic pathway. Analyses of the extant bacterial genomes showed that bioH is absent from many bioC-containing bacteria and is replaced by other genes. Helicobacter pylori lacks a gene encoding a homologue of the known pimeloyl-ACP methyl ester cleavage enzymes suggesting that it encodes a novel enzyme that cleaves this intermediate. We isolated the H. pylori gene encoding this enzyme, bioV, by complementation of an E. coli bioH deletion strain. Purified BioV cleaved the physiological substrate, pimeloyl-ACP methyl ester to pimeloyl-ACP by use of a catalytic triad, each member of which was essential for activity. The role of BioV in biotin biosynthesis was demonstrated using a reconstituted in vitro desthiobiotin synthesis system. BioV homologues seem the sole pimeloyl-ACP methyl ester esterase present in the Helicobacter species and their occurrence only in H. pylori and close relatives provide a target for development of drugs to specifically treat Helicobacter infections.

Helicobacter Species are Possible Risk Factors of Cholangiocarcinoma.

Several infectious agents are considered to be causes of cancer in human, mainly hepatitis B and C viruses, high-risk human pailloma viruses, Helicobacter pylori, Clonorchis sinensis, and Opisthorchis viverrini. Here we described the evident research and the association between Helicobacter spp. and biliary tract cancer particularly cholangiocarcinoma (CCA). Global epidemiological studies have suggested that Helicobacter spp. are possible risk factors for biliary tract diseases. Molecular studies support a linkage of Helicobacter spp. with CCA development. H. pylori, H. bilis, and H. hepaticus, are found in CCA, but the most common species are H. pylori and H. bilis. The type of CCA are associated with Helicobacter spp. include extrahepatic CCA, and common bile duct cancer. Up to the present, however, the results from different regions, materials and methods, sub-sites of cancer, and controls have not been consistent, thus introducing heterogeneity. Therefore, a comparison between co-Helicobacter spp.-CCA in the countries with low and high incident of CCA is required to settle the question. Furthermore, clarifying variation in the role of Helicobacter species in this CCA, including pathogenesis of CCA through enhanced biliary cell inflammation and proliferation, is necessary.

The Cytolethal Distending Toxin Subunit CdtB of Helicobacter Induces a Th17-related and Antimicrobial Signature in Intestinal and Hepatic Cells In Vitro.

Enterohepatic Helicobacter species are associated with several digestive diseases. Helicobacter pullorum is an emerging human foodborne pathogen, and Helicobacter hepaticus is a mouse pathogen; both species are associated with intestinal and/or hepatic diseases. They possess virulence factors, such as cytolethal distending toxin (CDT). Data indicate that CDT may be involved in chronic inflammatory responses, via its active subunit, CdtB. The proinflammatory properties of the CdtB of H. pullorum and H. hepaticus were assessed on human intestinal and hepatic epithelial cells in vitro. Interleukin 8 expression was evaluated by using wild-type strains and their corresponding CdtB isogenic mutants and by delivering CdtB directly into the cells. Nuclear factor κB nuclear translocation and transcriptomic characteristics in response to CdtB were also evaluated. The CdtB of these Helicobacter species induced nuclear factor κB nuclear translocation and exhibited proinflammatory properties, mainly the expression of T-helper type 17-related genes and genes encoding antimicrobial products also involved in cancer. The Histidine residue in position 265 of the CdtB catalytic site appeared to play a role in the regulation of most of these genes. As for flagellin or lipopolysaccharides, CdtB also induced expression of inflammation-associated genes related to antimicrobial activity.

Evidence of Helicobacter spp. in freshwaters from Roraima Tepui, Guayana Shield, South America.

Helicobacter presence and viability in waters is not well characterized. The identification of natural reservoirs and infection sources may provide novel insights into its waterborne transmission. The goal of this study was to investigated the occurrence of Helicobacter spp. in natural freshwaters from Roraima Tepui, a little studied and unique ecosystem of the Guayana Shield. Freshwaters collected from two localities at Roraima Tepui were cultured in HP selective broth and agar for Helicobacter pylori and analysed by fluorescent in situ hybridization (FISH), specific PCR assays, 16S rRNA gene sequencing and phylogenetic analysis. The presence of other bacteria in freshwater enrichments was determined using clone library sequencing of the 16S rRNA gene and phylogenetic inferences. Helicobacter spp. were detected by semi-nested PCR and FISH in freshwater enrichments from both sites. Coccoid viable but nonculturable (VBNC) cells were evidenced using 16S rRNA gene Helicobacter species and H. pylori-specific probes. Partial 16S rRNA gene sequences of two HP enrichments showed high similarity to H. pylori and Helicobacter nemestrinae (99-100 %). Other bacteria such as Serratia, Aquitalea, Chromobacterium, Mycobacterium, Acinetobacter, Curvibacter and Dysgonomonas were also detected using complete 16S rRNA gene sequences, with Serratia, Aquitalea and Chromobacterium the most common genera (40.9, 18.2 and 15.2 %, respectively). This is the first time that Helicobacter spp. have been reported in freshwaters of a tepui ecosystem. Our results contribute to the current knowledge of these bacteria in the aquatic environment and expand their known/potential sites outside the human host.

Helicobacter pullorum induces nitric oxide release in murine macrophages that promotes phagocytosis and killing.

Helicobacter pullorum is an avian enterohepatic species that, more recently, has also been found as a naturally acquired infection in mice and rats, and isolated from patients with gastrointestinal and hepatobiliary diseases. In this work, the interaction between H. pullorum and murine macrophages was examined. Firstly, the impact of nitric oxide, which is an antimicrobial produced by mammalian macrophages, on H. pullorum 6350-92 viability and morphology was studied by colony-forming assays and light microscopy, respectively. Exposure to nitric oxide lowered H. pullorum viability, in a growth-phase-dependent manner, and decreased the mean cell size. However, the number of coccoid forms remained low, contrasting with what has been observed for other Helicobacter species. Confocal microscopy showed that H. pullorum is internalized by murine macrophages, triggering nitric oxide production that promotes phagocytosis and killing of the pathogen. Interaction between H. pullorum and macrophages stimulated secretion of pro-inflammatory cytokines, such as TNF-α, IL-1β, IL-6 and MIP-2. These results show that H. pullorum is able to infect mammalian murine cells triggering an inflammatory response.

Abstract A098: Helicobacter-specific T cell responses in gut homeostasis and disease

Abstract The gastrointestinal tract is the major site for constant immunological challenge to the host immune system. The host must be able to mount protective immune responses against pathogenic micro-organisms while maintaining tolerance to most microbes under homeostatic conditions. A number of Helicobacter species, including Helicobacter hepaticus, have been isolated as the etiological agents of gastric ulcer disease or colitis in their respective hosts. H. hepaticus infection induces severe colitis in a number of immunocompromised mouse mutants, but interestingly does not usually cause disease in most WT mouse strains. Although Th17/Th1 responses are known to play an important role in H. hepaticus-mediated inflammation, how the immune response is contained such that it is harmless under homeostatic conditions and how perturbations lead to pathogenicity remain elusive questions. To answer these, it will be important to track H. hepaticus-specific T helper cells, which form a small proportion of total gut T helper cells, under homeostatic conditions. We have characterized TCRs specific for H. hepaticus antigens, which has allowed for development of TCR transgenic mice and MHCII tetramers to interrogate the specific T cell response that can contribute to inflammatory bowel disease in mouse models. Citation Format: Mo Xu, Dan R. Littman. Helicobacter-specific T cell responses in gut homeostasis and disease. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A098.

Detection of Helicobacter felis in a cat with gastric disease in laboratory animal facility.

A 3-month-old male cat in the animal facility was presented for investigation of anorexia and occasional vomiting. We collected the specimens from gastroscopic biopsy and stool collection. The gastroscopic biopsy specimens were tested using a rapid urease test, CLO Helicobacter-detection kits. Stool specimens were gathered and evaluated using the commercially available SD Bioline H. pylori Ag kit according to the manufacturer's instructions. Genomic DNAs from gastroscopic biopsy and stool specimens of the cat were extracted and submitted to the consensus PCR to amplify Helicobacter rpoB gene. Then the DNAs from gastroscopic biopsy and stool specimens were conducted a multiplex species-specific PCR to amplify urease B gene for H. heilmannii, H. pylori and H. felis. As the results, the rapid urease test with gastroscopic biopsy was revealed positive reaction. The result of H. pylori Stool Ag assay was one red line, negative for H. pylori. The gastroscopic biopsy and stool specimen were positive reactions by the consensus PCR reaction using the RNA polymerase beta-subunit-coding gene (rpoB) to detect Helicobacter species. By multiplex species-specific PCR with gastroscopic biopsy and stool specimens, no amplification products corresponding to either H. heilmannii or H. pylori were detected, but the specimens tested were positive for H. felis. This case was confirmed as gastroenteric disease induced by H. felis infection. On our knowledge, this is a very rare report about H. felis-induced gastroenteric disease in cat and may provide a valuable data on the study of feline Helicobacter infection.

Comparative Genomics of H. pylori and Non-Pylori Helicobacter Species to Identify New Regions Associated with Its Pathogenicity and Adaptability.

The genus Helicobacter is a group of Gram-negative, helical-shaped pathogens consisting of at least 36 bacterial species. Helicobacter pylori (H. pylori), infecting more than 50% of the human population, is considered as the major cause of gastritis, peptic ulcer, and gastric cancer. However, the genetic underpinnings of H. pylori that are responsible for its large scale epidemic and gastrointestinal environment adaption within human beings remain unclear. Core-pan genome analysis was performed among 75 representative H. pylori and 24 non-pylori Helicobacter genomes. There were 1173 conserved protein families of H. pylori and 673 of all 99 Helicobacter genus strains. We found 79 genome unique regions, a total of 202,359bp, shared by at least 80% of the H. pylori but lacked in non-pylori Helicobacter species. The operons, genes, and sRNAs within the H. pylori unique regions were considered as potential ones associated with its pathogenicity and adaptability, and the relativity among them has been partially confirmed by functional annotation analysis. However, functions of at least 54 genes and 10 sRNAs were still unclear. Our analysis of protein-protein interaction showed that 30 genes within them may have the cooperation relationship.

Detection of Helicobacter DNA in different water sources and penguin feces from Greenwich, Dee and Barrientos Islands, Antarctica

Helicobacter spp. colonize the gastrointestinal tract of humans and animals and have been associated with gastrointestinal diseases. Antarctic habitats are considered pristine ecosystems, but the increase in human activity could be introducing human bacteria hosted into waters and wildlife. However, Helicobacter spp. occurrence has not been studied in Antarctica. The aim of our study was to detect the Helicobacter DNA in different water sources and penguin feces from Greenwich, Dee and Barrientos Islands during summer of 2012 and 2013. High Helicobacter proportion was observed in water sources amplifying the 16S rRNA (33/40) and 23S rRNA genes (37/40) by semi-nested PCR. Similar results were observed in feces from Gentoo penguins (16S rRNA: 32/39, and 23S rRNA: 28/39) and Chinstrap penguins (16S rRNA: 16/17, and 23S rRNA: 15/17) by PCR. The phylogenetic relationship of 16S rRNA and 23S rRNA sequences from penguin feces was closely related to Helicobacter brantae. Analyses of 16S rRNA sequences showed that the majority of water samples are related to penguin (3/6) and Helicobacter pylori (2/6) sequences, but the 23S rRNA sequences matched with Campylobacter and Arcobacter. These results show for the first time the presence of the genus Helicobacter in different Antarctica water sources and in Gentoo and Chinstrap penguin feces. A few 16S rRNA sequences are very closely related to H. pylori, but specific glmM and ureAH. pylori genes were not detected. More studies are needed to determine the Helicobacter species present in this ecosystem and to establish the human impact in these Antarctic Islands.

Identification of Drug Targets in Helicobacter pylori by in silico Analysis: Possible Therapeutic Implications for Gastric cancer.

Helicobacter pylori colonize stomach, inducing gastritis, ulcers and gastric cancer. Drugs are used to relieve pain, but not H. pylori infections. Hence, there is a need for discovery of drug targets and drugs for H. pylori. An objective of this current study is to identify drug targets for H. pylori. RAST was used to compare genomes of 23 H. pylori strains with Homo sapiens sapiens, other Helicobacter species (H. acinonychis, H. hepaticus, H. mustalae) and among them, to identify 13471 unique genes. Bacterial genes which are non-homologous to humans and essential for pathogen are identified using BLASTp. Later, 29 potential drug targets were identified by subjecting these genes to property analysis. Eleven of the 29 drug targets are already experimentally validated, lending credence to our approach. These methods have enabled rapid identification of drug targets with possible therapeutic implications for gastric cancer.

Production of IFN-γ and IL-4 Against Intact Catalase and Constructed Catalase Epitopes of Helicobacter pylori From T-Cells.

Background:Helicobacter pylori infection is highly prevalent in the developing countries. It causes gastritis, peptic ulcer disease, and gastrocarcinoma. Treatment with drugs and antibiotics is problematic due to the following reasons: cost, resistance to antibiotics, prolonged treatment and using multiple drugs. Catalase is highly conserved among the Helicobacter species and is important to the survival of the organism. It is expressed in high amounts and is exposed to the surface of this bacterium; therefore it represents a suitable candidate vaccine antigen.Objectives:A suitable approach in H. pylori vaccinology is the administration of epitope based vaccines. Therefore the responses of T-cells (IFN-γ and IL-4 production) against the catalase of H. pylori were determined. Then the quality of the immune responses against intact catalase and three epitopes of catalase were compared.Materials and Methods:In this study, a composition of three epitopes of the H. pylori catalase was selected based on Propred software. The effect of catalase epitopes on T-cells were assayed and immune responses identified.Results:The results of IFN-γ, IL-4 production against antigens, epitopes, and recombinant catalase by T-cells were compared for better understanding of epitope efficiency.Conclusions:The current research demonstrated that epitope sequence stimulates cellular immune responses effectively. In addition, increased safety and potency as well as a reduction in time and cost were advantages of this method. Authors are going to use this sequence as a suitable vaccine candidate for further research on animal models and humans in future.