Effects of Oral Vaccination and Immunomodulation by Cholera Toxin on Experimental Helicobacter pylori Infection, Reinfection, and Gastritis

ABSTRACT Therapeutic vaccination is an attractive strategy to control infection and disease caused by Helicobacter pylori. In mice infected with H. pylori we have studied the protective effect of oral immunization with an H. pylori lysate preparation given together with the mucosal adjuvant cholera toxin (CT), both against the initial infection and against a later reinfection challenge. We have also examined the effects of treatment with the CT adjuvant alone on H. pylori infection and reinfection. Specific immunization with lysate was found to result in a sixfold reduction of the extent (bacterial load) of the primary infection and also to provide similar levels of protection against reinfection. However, these effects were associated with severe postimmunization gastritis. In contrast, oral treatment with CT alone at the time of initial infection, while unable to suppress the initial infection, gave rise to a 20-fold reduction in bacterial load upon reinfection without causing any associated gastric inflammation. Both the infected animals that were specifically immunized and those that were treated with CT only displayed increased in vitro proliferative responses of mononuclear cells to H. pylori antigens. Antibody levels in response to H. pylori were on the other hand only marginally increased after treatment with CT, whereas they were markedly elevated after immunization with lysate plus CT, with a rise in both (Th2-driven) immunoglobulin G1 (IgG1) and, especially, (Th1-driven) IgG2a antibodies. The results illustrate the complex balance between protection and harmful inflammation after postinfection vaccination against H. pylori as studied in a mouse model.

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Peroral immunization with Helicobacter pylori adhesin protein genetically linked to cholera toxin A2B subunits

Clinical Science ◽

10.1042/cs1000291 ◽

2001 ◽

Vol 100 (3) ◽

pp. 291-298 ◽

Cited By ~ 7

Author(s):

Byung Oh KIM ◽

Sung Seup SHIN ◽

Young Hyo YOO ◽

Suhkneung PYO

Keyword(s):

Helicobacter Pylori ◽

Cholera Toxin ◽

Vaccine Development ◽

Protective Antigen ◽

Oral Immunization ◽

Size Exclusion ◽

Vaccine Antigen ◽

Igg Antibodies ◽

Serum Igg ◽

H Pylori

Helicobacter pylori is a major cause of gastric-associated diseases. To evaluate the efficacy of a possible vaccine antigen against H. pylori infection, the chimaeric construct adhesin–CTXA2B, derived from H. pylori adhesin genetically coupled to cholera toxin (CTX) subunits A2 and B (CTXA2B), was expressed in Escherichia coli as an insoluble recombinant chimaeric protein. The protein was then purified by denaturation, renaturation and size-exclusion chromatography. The composition of purified adhesin–CTXA2B was verified by SDS/PAGE and Western blotting with antibodies to antigenic components of adhesin and CTXB, and confirmed as a chimaeric protein with GM1-ganglioside binding activity and adhesin epitopes by a GM1-ELISA developed using antibodies to adhesin. Oral immunization of mice with adhesin–CTXA2B induced higher levels of mucosal IgA and serum IgG antibodies to H. pylori adhesin and to CTXB than in mice immunized with adhesin or CTXA2B alone. Adhesin–CTXA2B was also demonstrated to be a potential protective antigen in a mouse model of H. pylori infection. The immunization of mice with adhesin–CTXA2B protected 62.5% of mice infected with H. pylori SS1 strain, whereas adhesin immunization was not able to confer protection to mice. This protection may be correlated with high levels of mucosal IgA and serum IgG antibodies against H. pylori adhesin. Taken together, the results indicate that the genetically linked CTXA2B acts as a useful mucosal adjuvant, and that the adhesin–CTXA2B chimaeric protein could be a potential component in future H. pylori vaccine development.

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Protection against Experimental Helicobacter pylori Infection after Immunization with Inactivated H. pylori Whole-Cell Vaccines

Infection and Immunity ◽

10.1128/iai.70.11.6383-6388.2002 ◽

2002 ◽

Vol 70 (11) ◽

pp. 6383-6388 ◽

Cited By ~ 43

Author(s):

S. Raghavan ◽

M. Hjulström ◽

J. Holmgren ◽

A.-M. Svennerholm

Keyword(s):

Helicobacter Pylori ◽

Protective Effect ◽

Cholera Toxin ◽

Oral Immunization ◽

Helicobacter Pylori Infection ◽

The Other ◽

Whole Cell ◽

O Antigen ◽

Lewis Antigen ◽

H Pylori

ABSTRACT The protective effect of therapeutic oral immunization with homologous and heterologous formalin-inactivated Helicobacter pylori cells given together with cholera toxin as an adjuvant was evaluated with C57BL/6 mice infected with H. pylori Sydney strain 1 (SS1). The bacteria used for immunization were strains that were either homologous or heterologous with regard to the O antigen (i.e., the Lewis antigen [Le antigen]) expressed by the lipopolysaccharide of the infecting H. pylori SS1 strain. We found that repeated oral immunization with inactivated H. pylori SS1 cells can significantly inhibit an existing infection (P < 0.001) and that the protection induced by such therapeutic immunization extends to protection against reinfection (P < 0.001). A similar level of protection was also achieved by immunization with another inactivated H. pylori strain having the same O antigen (Le antigen) as the infecting H. pylori SS1 strain. In contrast, immunization with inactivated strains expressing a heterologous O antigen, Lex, provided less protection or no protection. Immunization with H. pylori lysate preparations, on the other hand, resulted in significant comparable protection whether the lysates were prepared from an Lex strain or an Ley strain. Postimmunization gastritis was seen in mice that were protected after vaccination but not in unimmunized or unprotected mice. In conclusion, therapeutic immunization with inactivated H. pylori whole-cell vaccines may provide strong protection both against experimental H. pylori infection and against later reinfection.

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Systemic Th1 Immunization of Mice against Helicobacter pylori Infection with CpG Oligodeoxynucleotides as Adjuvants Does Not Protect from Infection but Enhances Gastritis

Infection and Immunity ◽

10.1128/iai.72.2.1029-1035.2004 ◽

2004 ◽

Vol 72 (2) ◽

pp. 1029-1035 ◽

Cited By ~ 20

Author(s):

Frank Sommer ◽

Henning Wilken ◽

Gerhard Faller ◽

Michael Lohoff

Keyword(s):

Immune Response ◽

Helicobacter Pylori ◽

Bacterial Load ◽

Oral Vaccination ◽

Cpg Oligodeoxynucleotides ◽

Fold Reduction ◽

Human Use ◽

H Pylori ◽

Subcutaneous Immunization ◽

Sterilizing Immunity

ABSTRACT Recent reports have suggested that oral vaccination of mice against Helicobacter pylori is dependent on a Th1-mediated immune response. However, oral vaccination in mice neither induces sterilizing immunity nor leads to complete protection from disease. Therefore, in this study we investigated whether a systemic subcutaneous immunization against H. pylori by using CpG oligodeoxynucleotides as a Th1 adjuvant could achieve protection in a mouse model of H. pylori infection. CpG oligodeoxynucleotides are known for their ability to induce nearly entirely Th1-biased immune responses and may be approved for human use in future. Immunization of mice with H. pylori lysate and CpG induced a strong local and systemic Th1 immune response. Despite this strong Th1 response, mice were not protected from infection with H. pylori yet had a 10-fold reduction in the number of H. pylori in the gastric mucosa compared to nonimmunized mice. Of note, reduction of the bacterial density in immunized mice was accompanied by a significantly enhanced gastritis. Hence, systemic Th1 immunization of mice, even though being able to reduce the bacterial load in the stomach, is associated with aggravated pathology.

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Enhanced Reduction of Helicobacter pylori Load in Precolonized Mice Treated with Combined Famotidine and Urease-Binding Polysaccharides

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.44.9.2492-2497.2000 ◽

2000 ◽

Vol 44 (9) ◽

pp. 2492-2497 ◽

Cited By ~ 7

Author(s):

Faustino C. Icatlo ◽

Nobutake Kimura ◽

Hideo Goshima ◽

Yoshikatsu Kodama

Keyword(s):

Helicobacter Pylori ◽

Dextran Sulfate ◽

Treatment Time ◽

Bacterial Load ◽

Positive Control ◽

Acid Inhibitor ◽

Enhanced Activity ◽

H Pylori

ABSTRACT The present study investigated the effect of a model urease-binding polysaccharide in combination with a histamine H2 receptor antagonist on Helicobacter pylori colonization in vivo. Euthymic hairless mice were treated daily with dextran sulfate via drinking water and/or famotidine via intragastric gavage starting at 1 week postchallenge with a CagA+ VacA+ (type 1) strain of H. pylori. Treatment of precolonized mice for 2 weeks with dextran sulfate combined with famotidine yielded a group mean bacterial load (per 100 mg of gastric tissue) of log101.04 CFU, which was significantly lower than those of the famotidine (log10 3.35 CFU, P < 0.01) and dextran sulfate (log10 2.45 CFU, P < 0.05) monotherapy groups and the infected nontreated group (log103.64 CFU, P < 0.01). Eradication was achieved after 2 weeks of treatment in 50% or more of the test mice using drug combinations (1 or 2 weeks of famotidine plus 2 weeks of dextran sulfate) versus none in the monotherapy and positive control groups. The enhanced activity of the drug combination may be related to the daily pattern of transient acid suppression by famotidine inducing periodic bacterial convergence to superficial mucus sites penetrated by dextran sulfate from the lumen. Increased urease-dextran sulfate avidity was observed in vitro in the presence of famotidine and may partly account for the enhanced activity. With potential utility in abbreviating treatment time and eradication of antibiotic-resistant strains, the use of urease-targeted polysaccharides concurrently with a gastric acid inhibitor warrants consideration as an additional component of the standard multidrug chemotherapy of H. pylori infection.

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Novel in vitro and in vivo anti-Helicobacter pylori effects of pomegranate peel ethanol extract

Veterinary World ◽

10.14202/vetworld.2021.120-128 ◽

2021 ◽

Vol 14 (1) ◽

pp. 120-128

Author(s):

Amal Mayyas ◽

Mohammad Abu-Sini ◽

Rula Amr ◽

Rand T. Akasheh ◽

Waleed Zalloum ◽

...

Keyword(s):

Helicobacter Pylori ◽

Synergistic Effect ◽

Oral Treatment ◽

Antimicrobial Properties ◽

Complementary Therapy ◽

Gastric Ulcers ◽

Pomegranate Peel ◽

H Pylori

Background and Aim: Interest in plants with antimicrobial properties has been revived due to emerging problems associated with using antibiotics to eradicate Helicobacter pylori. Accordingly, this study aims to assess the antibacterial effects of Punica granatum and the possible synergistic effect of its extract along with metronidazole against H. pylori. Materials and Methods: Pomegranate peel ethanol extracts (PPEE) was tested against a control strain of H. pylori (NCTC 11916) in vitro and in vivo in female Wistar rats. Moreover, the synergistic effect of PPEE in combination with metronidazole was tested in vitro. Results: The PPEE exhibited a remarkable activity against H. pylori with a minimum inhibitory concentration (MIC) of 0.156 mg/mL. Furthermore, the extract exhibited a pronounced urease inhibitory activity (IC50 ∼6 mg/mL) against the tested strain. A synergistic effect between PPEE and metronidazole was also observed (fractional inhibitory concentrations <0.5). Oral treatment of rats with PPEE for 8 days produced a significant reduction in H. pylori gastritis and a significant decrease in both lymphocytic and positive chronicity. Conclusion: Pomegranate extract is probably safe and represents a potential alternative and complementary therapy for reducing H. pylori associated with gastric ulcers.

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The rod-to-coccoid body transformation in cultures of Helicobacter pylori

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160686 ◽

1990 ◽

Vol 48 (3) ◽

pp. 626-627

Author(s):

A. R. Crooker ◽

W. G. Kraft ◽

T. L. Beard ◽

M. C. Myers

Keyword(s):

Helicobacter Pylori ◽

Growth Cycle ◽

Negative Bacterium ◽

Body Formation ◽

Coccoid Form ◽

Spiral Form ◽

Prolonged Culture ◽

H Pylori ◽

Upper Gastrointestinal

Helicobacter pylori is a microaerophilic, gram-negative bacterium found in the upper gastrointestinal tract of humans. There is strong evidence that H. pylori is important in the etiology of gastritis; the bacterium may also be a major predisposing cause of peptic ulceration. On the gastric mucosa, the organism exists as a spiral form with one to seven sheathed flagella at one (usually) or both poles. Short spirals were seen in the first successful culture of the organism in 1983. In 1984, Marshall and Warren reported a coccoid form in older cultures. Since that time, other workers have observed rod and coccal forms in vitro; coccoid forms predominate in cultures 3-7 days old. We sought to examine the growth cycle of H. pylori in prolonged culture and the mode of coccoid body formation.

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Synthesis and In Vitro Enzymatic Studies of New 3-Aryldiazenyl Indoles as Promising Helicobacter pylori IMPDH Inhibitors

Current Topics in Medicinal Chemistry ◽

10.2174/1568026619666190227212334 ◽

2019 ◽

Vol 19 (5) ◽

pp. 376-382 ◽

Cited By ~ 4

Author(s):

Sachin Jangra ◽

Gayathri Purushothaman ◽

Kapil Juvale ◽

Srimadhavi Ravi ◽

Aishwarya Menon ◽

...

Keyword(s):

Helicobacter Pylori ◽

Bacterial Infections ◽

Immunosuppressive Drugs ◽

Multi Drug Resistance ◽

Metabolic Enzyme ◽

World Population ◽

Inhibitor Molecule ◽

Nucleotide Synthesis ◽

H Pylori

Background & Objective:Helicobacter pylori infection is one of the primary causes of peptic ulcer followed by gastric cancer in the world population. Due to increased occurrences of multi-drug resistance to the currently available antibiotics, there is an urgent need for a new class of drugs against H. pylori. Inosine 5′-monophosphate dehydrogenase (IMPDH), a metabolic enzyme plays a significant role in cell proliferation and cell growth. It catalyses guanine nucleotide synthesis. IMPDH enzyme has been exploited as a target for antiviral, anticancer and immunosuppressive drugs. Recently, bacterial IMPDH has been studied as a potential target for treating bacterial infections. Differences in the structural and kinetic parameters of the eukaryotic and prokaryotic IMPDH make it possible to target bacterial enzyme selectively.Methods:In the current work, we have synthesised and studied the effect of substituted 3-aryldiazenyl indoles on Helicobacter pylori IMPDH (HpIMPDH) activity. The synthesised molecules were examined for their inhibitory potential against recombinant HpIMPDH.Results:In this study, compounds 1 and 2 were found to be the most potent inhibitors amongst the database with IC50 of 0.8 ± 0.02µM and 1 ± 0.03 µM, respectively.Conclusion:When compared to the most potent known HpIMPDH inhibitor molecule C91, 1 was only four-fold less potent and can be a good lead for further development of selective and potent inhibitors of HpIMPDH.

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Synthesis, Molecular Modelling and Antibacterial Activity Against Helicobacter pylori of Novel Diflunisal Derivatives as Urease Enzyme Inhibitors

Letters in Drug Design & Discovery ◽

10.2174/1570180815666180627130208 ◽

2019 ◽

Vol 16 (4) ◽

pp. 392-400 ◽

Cited By ~ 2

Author(s):

Göknil Pelin Coşkun ◽

Teodora Djikic ◽

Sadık Kalaycı ◽

Kemal Yelekçi ◽

Fikrettin Şahin ◽

...

Keyword(s):

Helicobacter Pylori ◽

Antibacterial Activity ◽

Enzyme Inhibitors ◽

Binding Modes ◽

Bacterial Strains ◽

Urease Enzyme ◽

H Pylori ◽

Ulcer Treatment ◽

Main Factor

Background:The main factor for the prolongation of the ulcer treatment in the gastrointestinal system would be Helicobacter pylori infection, which can possibly lead to gastrointestinal cancer. Triple therapy is the treatment of choice by today's standards. However, observed resistance among the bacterial strains can make the situation even worse. Therefore, there is a need to discover new targeted antibacterial therapy in order to make success in the eradication of H. pylori infections.Methods:The targeted therapy rule is to identify the related macromolecules that are responsible for the survival of the bacteria. Thus, 2-[(2',4'-difluoro-4-hydroxybiphenyl-3-yl)carbonyl]-N- (substituted)hydrazinocarbothioamide (3-13) and 5-(2',4'-difluoro-4-hydroxybiphenyl-3-yl)-4- (substituted)-2,4-dihydro-3H-1,2,4-triazole-3-thiones (14-17) were synthesized and evaluated for antibacterial activity in vitro against H. pylori.Results:All of the tested compounds showed remarkable antibacterial activity compared to the standard drugs (Ornidazole, Metronidazole, Nitrimidazin and Clarithromycin). Compounds 4 and 13 showed activity as 2µg/ml MIC value.Conclusion:In addition, we have investigated binding modes and energy of the compounds 4 and 13 on urease enzyme active by using the molecular docking tools.

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Myricetin as an Antivirulence Compound Interfering with a Morphological Transformation into Coccoid Forms and Potentiating Activity of Antibiotics against Helicobacter pylori

International Journal of Molecular Sciences ◽

10.3390/ijms22052695 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2695

Author(s):

Paweł Krzyżek ◽

Paweł Migdał ◽

Emil Paluch ◽

Magdalena Karwańska ◽

Alina Wieliczko ◽

...

Keyword(s):

Helicobacter Pylori ◽

Biofilm Formation ◽

Inhibitory Effect ◽

Morphological Transformation ◽

High Tendency ◽

Minimal Inhibitory Concentrations ◽

Coccoid Form ◽

Stomach Diseases ◽

Fold Reduction ◽

H Pylori

Helicobacter pylori, a gastric pathogen associated with a broad range of stomach diseases, has a high tendency to become resistant to antibiotics. One of the most important factors related to therapeutic failures is its ability to change from a spiral to a coccoid form. Therefore, the main aim of our original article was to determine the influence of myricetin, a natural compound with an antivirulence action, on the morphological transformation of H. pylori and check the potential of myricetin to increase the activity of antibiotics against this pathogen. We observed that sub-minimal inhibitory concentrations (sub-MICs) of this compound have the ability to slow down the process of transformation into coccoid forms and reduce biofilm formation of this bacterium. Using checkerboard assays, we noticed that the exposure of H. pylori to sub-MICs of myricetin enabled a 4–16-fold reduction in MICs of all classically used antibiotics (amoxicillin, clarithromycin, tetracycline, metronidazole, and levofloxacin). Additionally, RT-qPCR studies of genes related to the H. pylori morphogenesis showed a decrease in their expression during exposure to myricetin. This inhibitory effect was more strongly seen for genes involved in the muropeptide monomers shortening (csd3, csd6, csd4, and amiA), suggesting their significant participation in the spiral-to-coccoid transition. To our knowledge, this is the first research showing the ability of any compound to synergistically interact with all five antibiotics against H. pylori and the first one showing the capacity of a natural substance to interfere with the morphological transition of H. pylori from spiral to coccoid forms.

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Nutrient Deficiency Promotes the Entry of Helicobacter pylori Cells into Candida Yeast Cells

Biology ◽

10.3390/biology10050426 ◽

2021 ◽

Vol 10 (5) ◽

pp. 426

Author(s):

Kimberly Sánchez-Alonzo ◽

Fabiola Silva-Mieres ◽

Luciano Arellano-Arriagada ◽

Cristian Parra-Sepúlveda ◽

Humberto Bernasconi ◽

...

Keyword(s):

Helicobacter Pylori ◽

Nutrient Deficiency ◽

Gastric Epithelium ◽

Yeast Cells ◽

Nutrient Concentrations ◽

Fetal Bovine ◽

H Pylori ◽

Pcr Techniques ◽

Strain Dependent

Helicobacter pylori, a Gram-negative bacterium, has as a natural niche the human gastric epithelium. This pathogen has been reported to enter into Candida yeast cells; however, factors triggering this endosymbiotic relationship remain unknown. The aim of this work was to evaluate in vitro if variations in nutrient concentration in the cultured medium trigger the internalization of H. pylori within Candida cells. We used H. pylori–Candida co-cultures in Brucella broth supplemented with 1%, 5% or 20% fetal bovine serum or in saline solution. Intra-yeast bacteria-like bodies (BLBs) were observed using optical microscopy, while intra-yeast BLBs were identified as H. pylori using FISH and PCR techniques. Intra-yeast H. pylori (BLBs) viability was confirmed using the LIVE/DEAD BacLight Bacterial Viability kit. Intra-yeast H. pylori was present in all combinations of bacteria–yeast strains co-cultured. However, the percentages of yeast cells harboring bacteria (Y-BLBs) varied according to nutrient concentrations and also were strain-dependent. In conclusion, reduced nutrients stresses H. pylori, promoting its entry into Candida cells. The starvation of both H. pylori and Candida strains reduced the percentages of Y-BLBs, suggesting that starving yeast cells may be less capable of harboring stressed H. pylori cells. Moreover, the endosymbiotic relationship between H. pylori and Candida is dependent on the strains co-cultured.

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