Status of vaccine research and development for Helicobacter pylori

Rapid diagnosis and precision treatment of Helicobacter pylori infection in clinical settings

Helicobacter pylori is a gram-negative bacterium that colonizes the stomach of approximately half of the worldwide population, with higher prevalence in densely populated areas like Asia, the Caribbean, Latin America, and Africa. H. pylori infections range from asymptomatic cases to potentially fatal diseases, including peptic ulcers, chronic gastritis, and stomach adenocarcinoma. The management of these conditions has become more difficult due to the rising prevalence of drug-resistant H. pylori infections, which ultimately lead to gastric cancer and mucosa-associated lymphoid tissue (MALT) lymphoma. In 1994, the International Agency for Research on Cancer (IARC) categorized H. pylori as a Group I carcinogen, contributing to approximately 780,000 cancer cases annually. Antibiotic resistance against drugs used to treat H. pylori infections ranges between 15% and 50% worldwide, with Asian countries having exceptionally high rates. This review systematically examines the impacts of H. pylori infection, the increasing prevalence of antibiotic resistance, and the urgent need for accurate diagnosis and precision treatment. The present status of precision treatment strategies and prospective approaches for eradicating infections caused by antibiotic-resistant H. pylori will also be evaluated.

Immunoinformatic strategy for developing multi-epitope subunit vaccine against Helicobacter pylori

Helicobacter pylori is a gram-negative bacterium that persistently infects the human stomach, leading to peptic ulcers, gastritis, and an increased risk of gastric cancer. The extremophilic characteristics of this bacterium make it resistant to current drug treatments, and there are no licensed vaccines available against H. pylori. Computational approaches offer a viable alternative for designing antigenic, stable, and safe vaccines to control infections caused by this pathogen. In this study, we employed an immunoinformatic strategy to design a set of candidate multi-epitope subunit vaccines by combining the most potent B and T cell epitopes from three targeted antigenic proteins (BabA, CagA, and VacA). Out of the 12 hypothetical vaccines generated, two (HP_VaX_V1 and HP_VaX_V2) were found to be strongly immunogenic, non-allergenic, and structurally stable. The proposed vaccine candidates were evaluated based on population coverage, molecular docking, immune simulations, codon adaptation, secondary mRNA structure, and in silico cloning. The vaccine candidates exhibited antigenic scores of 1.19 and 1.01, with 93.5% and 90.4% of the most rama-favored regions, respectively. HP_VaX_V1 and HP_VaX_V2 exhibited the strongest binding affinity towards TLR-7 and TLR-8, as determined by molecular docking simulations (ΔG = -20.3 and -20.9, respectively). Afterward, multi-scale normal mode analysis simulation revealed the structural flexibility and stability of vaccine candidates. Additionally, immune simulations showed elevated levels of cell-mediated immunity, while repeated exposure simulations indicated rapid antigen clearance. Finally, in silico cloning was performed using the expression vector pET28a (+) with optimized restriction sites to develop a viable strategy for large-scale production of the chosen vaccine constructs. These analyses suggest that the proposed vaccines may elicit potent immune responses against H. pylori, but laboratory validation is needed to verify their safety and immunogenicity.

Leveraging immunoinformatics for developing a multi-epitope subunit vaccine against Helicobacter pylori and Fusobacterium nucleatum

Gastric ulcers caused by Helicobacter pylori and Fusobacterium nucleatum remain a significant global health concern without an established vaccine. In this study, we utilized immunoinformatics methods to design a multi-epitope vaccine targeting these pathogens. Outer membrane proteins from H. pylori and F. nucleatum were scrutinized to identify high antigenic T-cell and B-cell epitopes. The resulting vaccine comprised carefully analyzed and evaluated epitopes, including cytotoxic T-lymphocytes, helper T-lymphocytes, and linear B-lymphocytes epitopes. This vaccine exhibited notable antigenicity, suitable immunogenicity, and demonstrated non-allergenicity and non-toxicity. It displayed favorable physiochemical characteristics and high solubility. In interaction studies, the vaccine exhibited robust binding to toll-like receptor 4 (TLR4). Molecular dynamic simulations revealed cohesive structural integrity and stable attachment. Codon adaptation utilizing Escherichia coli K12 host yielded a vaccine with elevated Codon Adaptation Index (CAI) and optimal GC content. In silico cloning into the pET28+(a) vector demonstrated efficient expression. Immune simulations indicated the vaccine's ability to initiate immune responses in humans, mirroring real-life scenarios. Based on these comprehensive findings, we propose that our developed vaccine has the potential to confer robust immunity against H. pylori and F. nucleatum infections.Communicated by Ramaswamy H. Sarma.

Pivotal role of Helicobacter pylori virulence genes in pathogenicity and vaccine development

One of the most prevalent human infections is Helicobacter pylori (H. pylori), which affects more than half of the global population. Although H. pylori infections are widespread, only a minority of individuals develop severe gastroduodenal disorders. The global resistance of H. pylori to antibiotics has reached concerning levels, significantly impacting the effectiveness of treatment. Consequently, the development of vaccines targeting virulence factors may present a viable alternative for the treatment and prevention of H. pylori infections. This review aims to provide a comprehensive overview of the current understanding of H. pylori infection, with a particular focus on its virulence factors, pathophysiology, and vaccination strategies. This review discusses various virulence factors associated with H. pylori, such as cytotoxin-associated gene A (cagA), vacuolating cytotoxin gene (vacA), outer membrane proteins (OMPs), neutrophil-activated protein (NAP), urease (ure), and catalase. The development of vaccines based on these virulence characteristics is essential for controlling infection and ensuring long-lasting protection. Various vaccination strategies and formulations have been tested in animal models; however, their effectiveness and reproducibility in humans remain uncertain. Different types of vaccines, including vector-based vaccines, inactivated whole cells, genetically modified protein-based subunits, and multiepitope nucleic acid (DNA) vaccines, have been explored. While some vaccines have demonstrated promising results in murine models, only a limited number have been successfully tested in humans. This article provides a thorough evaluation of recent research on H. pylori virulence genes and vaccination methods, offering valuable insights for future strategies to address this global health challenge.

Developing a multi-epitope vaccine against Helicobacter Pylori

Helicobacter pylori, a significant factor in the development of gastric cancer and peptic ulcers, poses challenges for drug development due to its resilience. Computational approaches offer potential solutions for effective vaccine development targeting its antigens while ensuring stability and safety. The four critical antigenic proteins included in this study's innovative vaccine design are neuraminyllactose-binding hemagglutinin (HpaA), catalase (KatA), urease (UreB), and vacuolating toxin (VacA). Advanced immunoinformatics methods identified the possibility of triggering an immunological reaction. An adjuvant (50S ribosomal protein L7/L12) was fused to the vaccine sequence's N-terminus to improve immunogenicity. GROMACS molecular dynamics simulations with the OPLS-AA force field further improved the structure. The vaccine design and human Toll-like receptor 5 (TLR5) demonstrated a strong binding in docking tests. A model of simulating immune response confirmed the vaccine's efficacy and predicted how it would affect the immune system. Using the optimal restriction sites of the pET28b (+) expression vector, the vaccine candidate was cloned in silico. To validate the findings, this vaccine design will be synthesized in a bacterial system, and in experimental studies will be conducted in the following phase.

Helicobacter pylori: Routes of Infection, Antimicrobial Resistance, and Alternative Therapies as a Means to Develop Infection Control

Helicobacter pylori (H. pylori) is a Gram-negative, spiral-shaped bacterium that colonizes the gastric epithelium and is associated with a range of gastrointestinal disorders, exhibiting a global prevalence of approximately 50%. Despite the availability of treatment options, H. pylori frequently reemerges and demonstrates increasing antibiotic resistance, which diminishes the efficacy of conventional therapies. Consequently, it is imperative to explore non-antibiotic treatment alternatives to mitigate the inappropriate use of antibiotics. This review examines H. pylori infection, encompassing transmission pathways, treatment modalities, antibiotic resistance, and eradication strategies. Additionally, it discusses alternative therapeutic approaches such as probiotics, anti-biofilm agents, phytotherapy, phototherapy, phage therapy, lactoferrin therapy, and vaccine development. These strategies aim to reduce antimicrobial resistance and enhance treatment outcomes for H. pylori infections. While alternative therapies can maintain low bacterial levels, they do not achieve complete eradication of H. pylori. These therapies are designed to bolster the immune response, minimize side effects, and provide gastroprotective benefits, rendering them suitable for adjunctive use alongside conventional treatments. Probiotics may serve as adjunctive therapy for H. pylori; however, their effectiveness as a monotherapy is limited. Photodynamic and phage therapies exhibit potential in targeting H. pylori infections, including those caused by drug-resistant strains, without the use of antibiotics. The development of a reliable vaccine is also critical for the eradication of H. pylori. This review identifies candidate antigens such as VacA, CagA, and HspA, along with various vaccine formulations, including vector-based and subunit vaccines. Some vaccines have demonstrated efficacy in clinical trials, while others have shown robust immune protection in preclinical studies. Nevertheless, each of the aforementioned alternative therapies requires thorough preclinical and clinical evaluation to ascertain their efficacy, side effects, cost-effectiveness, and patient compliance.

Developing a potent vaccine against Helicobacter pylori: critical considerations and challenges

Helicobacter pylori (H. pylori) is closely associated with gastric cancer and peptic ulcers. The effectiveness of antibiotic treatment against H. pylori is diminished by the emergence of drug-resistant strains, side effects, high cost and reinfections. Given the circumstances, it is imperative to develop a potent vaccination targeting H. pylori. Understanding H. pylori's pathogenicity and the host's immune response is essential to developing a vaccine. Furthermore, vaccine evaluation necessitates the careful selection of design formulation. This review article aims to provide a concise overview of the considerations involved in selecting the optimal antigen, adjuvant, vaccine delivery system and laboratory animal model for vaccine formulation. Furthermore, we will discuss some significant obstacles in the realm of developing a potent vaccination against H. pylori.

Drug development in LMICs: could the emerging Indian model usher the southeast Asian region?

Low-income and middle-income countries (LMICs) of southeast Asia are passing through a similar phase as India in their tryst with the development of novel drugs. They are beginning to break away from their dependency on the institutions of our developed world. Over the past few years, Tata Memorial Centre-India's premier cancer centre-has shown the tenacity to develop drugs within the national frontiers. By collaborating with the domestic pharmaceutical industries, it has been able to have a steady pipeline of drugs under development, with two of them receiving marketing authorization recently. Lately, Indonesia and Vietnam have also shown an inclination towards public-private partnerships for similar motives. However, due to prolonged innovative stagnation, the entire drug development machinery faces challenges stretching all the way from arranging funds to persuading regulatory bodies. In this Viewpoint, we have tried to address a few of those issues and their potential solutions, with the intention to share our own experience which might be useful to other LMICs in connecting some adamant dots.

Design of a Helicobacter pylori multi-epitope vaccine based on immunoinformatics

Helicobacter pylori (H. pylori) is an infectious bacterium that colonizes the stomach of approximately half of the global population. It has been classified as a Group I carcinogen by the World Health Organization due to its strong association with an increased incidence of gastric cancer and exacerbation of stomach diseases. The primary treatment for H. pylori infection currently involves triple or quadruple therapy, primarily consisting of antibiotics and proton pump inhibitors. However, the increasing prevalence of antibiotic resistance poses significant challenges to this approach, underscoring the urgent need for an effective vaccine. In this study, a novel multi-epitope H. pylori vaccine was designed using immunoinformatics. The vaccine contains epitopes derived from nine essential proteins. Software tools and online servers were utilized to predict, evaluate, and analyze the physiochemical properties, secondary and tertiary structures, and immunogenicity of the candidate vaccine. These comprehensive assessments ultimately led to the formulation of an optimal design scheme for the vaccine. Through constructing a novel multi-epitope vaccine based on immunoinformatics, this study offers promising prospects and great potential for the prevention of H. pylori infection. This study also provides a reference strategy to develop multi-epitope vaccines for other pathogens.

Immunoinformatics design and synthesis of a multi-epitope vaccine against Helicobacter pylori based on lipid nanoparticles

Helicobacter pylori (H. pylori) is responsible for various chronic or acute diseases, such as stomach ulcers, dyspepsia, peptic ulcers, gastroesophageal reflux, gastritis, lymphoma, and stomach cancers. Although specific drugs are available to treat the bacterium's harmful effects, there is an urgent need to develop a preventive or therapeutic vaccine. Therefore, the current study aims to create a multi-epitope vaccine against H. pylori using lipid nanoparticles. Five epitopes from five target proteins of H. pylori, namely, Urease, CagA, HopE, SabA, and BabA, were used. Immunogenicity, MHC (Major Histocompatibility Complex) bonding, allergenicity, toxicity, physicochemical analysis, and global population coverage of the entire epitopes and final construct were carefully examined. The study involved using various bioinformatic web tools to accomplish the following tasks: modeling the three-dimensional structure of a set of epitopes and the final construct and docking them with Toll-Like Receptor 4 (TLR4). In the experimental phase, the final multi-epitope construct was synthesized using the solid phase method, and it was then enclosed in lipid nanoparticles. After synthesizing the construct, its loading, average size distribution, and nanoliposome shape were checked using Nanodrop at 280 nm, dynamic light scattering (DLS), and atomic force microscope (AFM). The designed vaccine has been confirmed to be non-toxic and anti-allergic. It can bind with different MHC alleles at a rate of 99.05%. The construct loading was determined to be about 91%, with an average size of 54 nm. Spherical shapes were also observed in the AFM images. Further laboratory tests are necessary to confirm the safety and immunogenicity of the multi-epitope vaccine.

Unveiling the potential role of micro/nano biomaterials in the treatment of Helicobacter pylori infection

INTRODUCTION

Helicobacter pylori causes stubborn infections and leads to a variety of stomach disorders, such as peptic ulcer, chronic atrophic gastritis, and gastric cancer. Although antibiotic-based approaches have been widely used against H. pylori, some challenges such as antibiotic resistance are increasing in severity. Therefore, simpler but more effective strategies are needed.

AREAS COVERED

In this review, basic information on functionalized and non-functionalized micro/nano biomaterials and routes of administration for H. pylori inhibition are provided in an easy-to-understand format. Afterward, in vitro and in vivo studies of some promising bio-platforms including metal-based biomaterials, biopolymers, small-molecule saccharides, and vaccines for H. pylori inhibition are discussed in a holistic manner.

EXPERT OPINION

Functionalized or non-functionalized micro/nano biomaterials loaded with anti-H. pylori agents can show efficient bactericidal activity with no/slight negative influence on the host gastrointestinal microbiota. However, this claim needs to be substantiated with hard data such as assessment of the biopharmaceutical parameters of anti-H. pylori systems and the measurement of diversity/abundance of bacterial genera in the host gastric/gut microbiota before and after H. pylori eradication.

Peptic ulcer disease

Annual prevalence estimates of peptic ulcer disease range between 0·12% and 1·5%. Peptic ulcer disease is usually attributable to Helicobacter pylori infection, intake of some medications (such as aspirin and non-steroidal anti-inflammatory medications), or being critically ill (stress-related), or it can be idiopathic. The clinical presentation is usually uncomplicated, with peptic ulcer disease management based on eradicating H pylori if present, the use of acid-suppressing medications-most often proton pump inhibitors (PPIs)-or addressing complications, such as with early endoscopy and high-dose PPIs for peptic ulcer bleeding. Special considerations apply to patients on antiplatelet and antithrombotic agents. H pylori treatment has evolved, with the choice of regimen dictated by local antibiotic resistance patterns. Indications for primary and secondary prophylaxis vary across societies; most suggest PPIs for patients at highest risk of developing a peptic ulcer, its complications, or its recurrence. Additional research areas include the use of potassium-competitive acid blockers and H pylori vaccination; the optimal approach for patients at risk of stress ulcer bleeding requires more robust determinations of optimal patient selection and treatment selection, if any. Appropriate continuation of PPI use outweighs most possible side-effects if given for approved indications, while de-prescribing should be trialled when a definitive indication is no longer present.

Animal Models of Helicobacter pylori Infection and Vaccines: Current Status and Future Prospects

Helicobacter pylori infection causes chronic gastritis, ulcers, and gastric cancer, making it a threat to human health. Despite the use of antibiotic therapy, the global prevalence of H. pylori infection remains high, necessitating early eradication measures. Immunotherapy, especially vaccine development, is a promising solution in this direction, albeit the selection of an appropriate animal model is critical in efficient vaccine production. Accordingly, we conducted a literature, search and summarized the commonly used H. pylori strains, H. pylori infection-related animal models, and models for evaluating H. pylori vaccines. Based on factors such as the ability to replicate human diseases, strain compatibility, vaccine types, and eliciting of immune responses, we systematically compared the advantages and disadvantages of different animal models, to obtain the informed recommendations. In addition, we have proposed novel perspectives on H. pylori-related animal models to advance research and vaccine evaluation for the prevention and treatment of diseases such as gastric cancer.

Novel therapeutic regimens against Helicobacter pylori: an updated systematic review

Helicobacter pylori (H. pylori) is a strict microaerophilic bacterial species that exists in the stomach, and H. pylori infection is one of the most common chronic bacterial infections affecting humans. Eradicating H. pylori is the preferred method for the long-term prevention of complications such as chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. However, first-line treatment with triple therapy and quadruple therapy has been unable to cope with increasing antibacterial resistance. To provide an updated review of H. pylori infections and antibacterial resistance, as well as related treatment options, we searched PubMed for articles published until March 2024. The key search terms were "H. pylori", "H. pylori infection", "H. pylori diseases", "H. pylori eradication", and "H. pylori antibacterial resistance." Despite the use of antimicrobial agents, the annual decline in the eradication rate of H. pylori continues. Emerging eradication therapies, such as the development of the new strong acid blocker vonoprazan, probiotic adjuvant therapy, and H. pylori vaccine therapy, are exciting. However, the effectiveness of these treatments needs to be further evaluated. It is worth mentioning that the idea of altering the oxygen environment in gastric juice for H. pylori to not be able to survive is a hot topic that should be considered in new eradication plans. Various strategies for eradicating H. pylori, including antibacterials, vaccines, probiotics, and biomaterials, are continuously evolving. A novel approach involving the alteration of the oxygen concentration within the growth environment of H. pylori has emerged as a promising eradication strategy.

An Immunoinformatic Approach to Designing a Multi-epitope Vaccine against Helicobacter pylori with the VacA Toxin and BabA Adhesion

Objective:

Helicobacter pylori, as a carcinogen, has been related to the development of gastric cancer, particularly in developing countries. The main challenge with therapy is the recurrence of antibiotic-resistant bacteria, and vaccination is still a problem. Therefore, the objective of the current study was to rationally design a multi-epitope vaccine using two immunogenic proteins found in H. pylori.

Methods:

Promising epitopes for the Leb-binding adhesin A (BabA) and vacuolating cytotoxin (VacA) proteins were characterized through an immunoinformatics approach. Epitope-rich fragments were selected based on high-binding affinities with HLA classes I and II to be specifically presented to B and T lymphocytes and to selectively elicit both humoral and cellular immune responses.

Results:

Six constructs were planned by fusing these fragments in different arrangements with the help of GPGPG linkers. The most stable three-dimensional structure was found in Construct 6 during molecular dynamics. To improve immunogenicity and stability, an adjuvant called human β- defensin 2 (hBD-2) was joined to the N-terminus of Construct 6. Following molecular docking, the final vaccine reacted appropriately with each toll-like receptor 2 (TLR-2), TLR3, and TLR-4. The final DNA sequence was optimized for expression in E. coli K12 and in silico cloned into a pET-28a(+) plasmid. As a result of the vaccination in silico, substantial responses were developed against H. pylori.

Conclusion:

According to the immune response simulation, activated B and T lymphocytes and memory cell production increased. Macrophages and dendritic cells proliferated continuously, and IFN-γ and Cytokines, such as IL-2 were raised.

Revolution of Helicobacter pylori treatment

Helicobacter pylori infection is a major global health concern, and its management has witnessed a revolutionary shift with the emergence of antibiotic resistance. In this review, I explore the mechanisms of H. pylori antibiotic resistance and highlight the critical need for susceptibility-based eradication treatments. The increasing prevalence of antibiotic-resistant strains requires innovative approaches to combat this resilient pathogen. I also delve into the importance of mass screening as a preventive strategy for early detection and intervention, describing my experience in Bhutan. Additionally, I explore promising alternatives, such as vaccination. The aim of this review is to provide insight into the evolving landscape of H. pylori treatment and highlight the need for a paradigm shift in the approach to combating this persistent bacterial infection.

Immunoinformatics design of a structural proteins driven multi-epitope candidate vaccine against different SARS-CoV-2 variants based on fynomer

The ideal vaccines for combating diseases that may emerge in the future require more than simply inactivating a few pathogenic strains. This study aims to provide a peptide-based multi-epitope vaccine effective against various severe acute respiratory syndrome coronavirus 2 strains. To design the vaccine, a library of peptides from the spike, nucleocapsid, membrane, and envelope structural proteins of various strains was prepared. Then, the final vaccine structure was optimized using the fully protected epitopes and the fynomer scaffold. Using bioinformatics tools, the antigenicity, allergenicity, toxicity, physicochemical properties, population coverage, and secondary and three-dimensional structures of the vaccine candidate were evaluated. The bioinformatic analyses confirmed the high quality of the vaccine. According to further investigations, this structure is similar to native protein and there is a stable and strong interaction between vaccine and receptors. Based on molecular dynamics simulation, structural compactness and stability in binding were also observed. In addition, the immune simulation showed that the vaccine can stimulate immune responses similar to real conditions. Finally, codon optimization and in silico cloning confirmed efficient expression in Escherichia coli. In conclusion, the fynomer-based vaccine can be considered as a new style in designing and updating vaccines to protect against coronavirus disease.

WITHDRAWN: PIRES2-EGFP/CTB-UreI vaccination activated a mixed Th1/Th2/Th17 immune system defense towards Helicobacter pylori infection in the BALB/c mice model

This article has been withdrawn at the request of the Editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/policies/article-withdrawal. The data presented in the manuscript was deemed severely flawed after appearing online as an Article in Press. The scientific community raised concerns about the methodology (including but not limited to major technical issues) used in the study and the subsequent conclusions drawn from the presented experiments. After careful investigation, the Vaccine editorial office concluded that the data in the publication was indeed severely flawed and that the concerns raised by the scientific community were valid. Therefore, the journal editors decided to withdraw the article and sincerely apologize for any inconvenience caused.

[Cost-effectiveness analysis of a vaccine for Helicobacter pylori in southern Europe]

OBJECTIVE

There is sufficient evidence on the feasibility of a vaccine to prevent Helicobacter pylori infection. Modeling studies in low prevalence environments report a very probable long-term cost-effectiveness. The objective of this study was to quantify its efficiency in a local context.

METHODS

The evolution of a cohort of newborns was simulated through a compartmental model representing a series of clinical situations regarding H. pylori infection and related diseases. The model was run under the assumption of both vaccination in the first year of life and no intervention. The time horizon was set as equivalent to the life expectancy and the perspective of the health system was taken into account.

RESULTS

Vaccination against H. pylori would cost an average of €2,168/person more than no intervention. This would yield an average additional 0.32 quality-adjusted life years gained (QALY), which would entail an incremental cost-effectiveness ratio (ICER) of €7,196/QALY. For a willingness to pay of €24,506/QALY, 99.96% of the simulations were cost-effective at eighty-four years old. This threshold was crossed thirty years after vaccination. The variables that carried the most weight in explaining the variability of the ICER were, in this order, vaccine effectiveness, the incidence of infection in young children, and the price of the vaccine. Vaccination would cease to be cost-effective with a price greater than €3,634/dose or with effective population coverage less than 11%.

CONCLUSIONS

When implemented in an environment with the epidemiological and economic characteristics of Southern Europe, a prophylactic vaccination against H. pylori would be cost-effective in the long run.

An M cell-targeting recombinant L. lactis vaccine against four H. pylori adhesins

The acidic environment and enzyme degradation lead to oral vaccines often having little immune effect. Therefore, it is an attractive strategy to study an effective and safe oral vaccine delivery system that can promote gastrointestinal mucosal immune responses and inhibit antigen degradation. Moreover, the antigens uptake by microfold cells (M cells) is the determining step in initiating efficient immune responses. Therefore, M cell-targeting is one promising approach for enhancing oral vaccine potency. In the present study, an M cell-targeting L. lactis surface display system (plSAM) was built to favor the multivalent epitope vaccine antigen (FAdE) to achieve effective gastrointestinal mucosal immunity against Helicobacter pylori. Therefore, a recombinant Lactococcus lactic acid vaccine (LL-plSAM-FAdE) was successfully prepared, and its immunological properties and protective efficacy were analyzed. The results showed that LL-plSAM-FAdE can secretively express the recombinant proteins SAM-FAdE and display the SAM-FAdE on the bacterial cell surface. More importantly, LL-plSAM-FAdE effectively promoted the phagocytosis and transport of vaccine antigen by M cells in the gastrointestinal tract of mice, and simulated high levels of cellular and humoral immune responses against four key H. pylori adhesins (Urease, CagL, HpaA, and Lpp20) in the gastrointestinal tract, thus enabling effective prevention of H. pylori infection and to some extent eliminating H. pylori already present in the gastrointestinal tract. KEY POINTS: • M-cell-targeting L. lactis surface display system LL- plSAM was designed • This system displays H. pylori vaccine-promoted phagocytosis and transport of M cell • A promising vaccine candidate for controlling H. pylori infection was verified.

Helicobacter pylori

Helicobacter pylori (H. pylori) is an important human pathogen etiologically associated with peptic ulcers and gastric cancer. The infection is present in approximately one-half of the world's population. Population-based H. pylori eradiation has confirmed that cure or prevention of the infection produces a marked reduction in gastric cancer and peptic ulcer disease. Antimicrobial therapy has become increasingly ineffective, and complexity and costs of antimicrobial therapy for infected individuals residing in and, immigrating from, the developing world combined with the cost of treatment for cancer make vaccine development a cost-effective alternative. Challenge studies allowed making a "go-no go" decision regarding vaccine effectiveness. We provide detailed protocols regarding challenge strain selection and administration as well as guidance regarding the clinical and laboratory tests used to confirm and monitor experimental infection. Experience shows that reliance of noninvasive methods led to the erroneous conclusion that some subjects were not infected. The current data suggests that histologic assessment of gastric mucosal biopsies may be one of the most sensitive and specific means of assessment of the presence of experimental infection as well as of successful H. pylori eradication. We recommend detailed recommendations for acquiring, processing, embedding, sectioning, and examining the gastric biopsies.

Identification of the immunogenic membrane proteins, catalase, PgbA, and PgbB, as potential antigens against Helicobacter pylori

AIMS

This study aims to investigate the specific membrane antigens that are targeted by antibodies raised against Helicobacter pylori.

METHODS AND RESULTS

Bovine milk antibodies were prepared using whole H. pylori, purified membrane proteins, or both. Enzyme-linked immunosorbent assay and sodium dodecyl sulfate-polyacrylamide gel electrophoresis experiments revealed that these immunogens triggered anti-H. pylori antibody production in milk. The highest antibody titer was induced by the mixture of whole bacteria and purified membrane proteins. The antibodies induced by mixed immunogens significantly inhibited H. pylori growth in vitro and were used to identify catalase, plasminogen-binding protein A (PgbA), and PgbB via western blotting, immunoprecipitation, and two-dimensional western blotting followed by liquid chromatography with tandem mass spectrophotometry. The immunogenicity of PgbA and PgbB was verified in mice vaccinated with their B-cell epitope vaccines. Following prophylactic vaccination of C57BL/6 mice, each of the three antigens alone and their combination reduced the weight loss in mice, increased antibody titers, and relieved the inflammatory status of the gastric mucosa following H. pylori infection.

CONCLUSIONS

Catalase, PgbA, and PgbB could serve as valuable membrane antigens for the development of anti-H. pylori immunotherapies.

Designing and development of multi-epitope chimeric vaccine against Helicobacter pylori by exploring its entire immunogenic epitopes: an immunoinformatic approach

BACKGROUND

Helicobacter pylori is a prominent causative agent of gastric ulceration, gastric adenocarcinoma and gastric lymphoma and have been categorised as a group 1 carcinogen by WHO. The treatment of H. pylori with proton pump inhibitors and antibiotics is effective but also leads to increased antibiotic resistance, patient dissatisfaction, and chances of reinfection. Therefore, an effective vaccine remains the most suitable prophylactic option for mass administration against this infection.

RESULTS

We modelled a multi-chimera subunit vaccine candidate against H. pylori by screening its secretory/outer membrane proteins. We identified B-cell, MHC-II and IFN-γ-inducing epitopes within these proteins. The population coverage, antigenicity, physiochemical properties and secondary structure were evaluated using different in-silico tools, which showed it can be a good and effective vaccine candidate. The 3-D construct was predicted, refined, validated and docked with TLRs. Finally, we performed the molecular docking/simulation and immune simulation studies to validate the stability of interaction and in-silico cloned the epitope sequences into a pET28b(+) plasmid vector.

CONCLUSION

The multiepitope-constructed vaccine contains T- cells, B-cells along with IFN-γ inducing epitopes that have the property to generate good cell-mediated immunity and humoral response. This vaccine can protect most of the world's population. The docking study and immune simulation revealed a good binding with TLRs and cell-mediated and humoral immune responses, respectively. Overall, we attempted to design a multiepitope vaccine and expect this vaccine will show an encouraging result against H. pylori infection in in-vivo use.

Vaccination against Helicobacter pylori - An approach for cancer prevention?

The gram-negative bacterium Helicobacter pylori is the most common chronic bacterial infection and the main cause of gastric cancer. Due to the increasing antimicrobial resistance of H. pylori, the development of an efficacious vaccine is a valid option to protect from disease or infection and ultimately prevent gastric cancer. However, despite more than 30 years of research, no vaccine has entered the market yet. This review highlights the most relevant previous preclinical and clinical studies to allow conclusions to be drawn on which parameters need special attention in the future to develop an efficacious vaccine against H. pylori and thus prevent gastric cancer.

Vaccination with Helicobacter pylori attachment proteins protects against gastric cancer

Most cases of gastric cancer are caused by chronic Helicobacter pylori infection, but the lack of early onco-diagnostics and a high risk for antibiotic resistance hampers early intervention through eradication of H. pylori infection by antibiotics. We reported on a protective mechanism where H. pylori gastric mucosal attachment can be reduced by natural antibodies that block the binding of its attachment protein BabA. Here we show that challenge infection with H. pylori induced response of such blocking antibodies in both human volunteers and in rhesus macaques, that mucosal vaccination with BabA protein antigen induced blocking antibodies in rhesus macaques, and that vaccination in a mouse model induced blocking antibodies that reduced gastric mucosal inflammation, preserved the gastric juice acidity, and fully protected the mice from gastric cancer caused by H. pylori.

Helicobacter pylori attachment-blocking antibodies protect against duodenal ulcer disease

The majority of the world population carry the gastric pathogen Helicobacter pylori. Fortunately, most individuals experience only low-grade or no symptoms, but in many cases the chronic inflammatory infection develops into severe gastric disease, including duodenal ulcer disease and gastric cancer. Here we report on a protective mechanism where H. pylori attachment and accompanying chronic mucosal inflammation can be reduced by antibodies that are present in a vast majority of H. pylori carriers. These antibodies block binding of the H. pylori attachment protein BabA by mimicking BabA's binding to the ABO blood group glycans in the gastric mucosa. However, many individuals demonstrate low titers of BabA blocking antibodies, which is associated with an increased risk for duodenal ulceration, suggesting a role for these antibodies in preventing gastric disease.

A review on the research progress on non-pharmacological therapy of Helicobacter pylori

Helicobacter pylori is a pathogenic microorganism that mainly resides in the human stomach and is the major cause of chronic gastritis, peptic ulcer and gastric cancer. Up to now, the treatment of Helicobacter pylori has been predominantly based on a combination of antibiotics and proton pump inhibitors. However, the increasing antibiotic resistance greatly limits the efficacy of anti-Helicobacter pylori treatment. Turning to non-antibiotic or non-pharmacological treatment is expected to solve this problem and may become a new strategy for treating Helicobacter pylori. In this review, we outline Helicobacter pylori's colonization and virulence mechanisms. Moreover, a series of non-pharmacological treatment methods for Helicobacter pylori and their mechanisms are carefully summarized, including probiotics, oxygen-rich environment or hyperbaric oxygen therapy, antibacterial photodynamic therapy, nanomaterials, antimicrobial peptide therapy, phage therapy and modified lysins. Finally, we provide a comprehensive overview of the challenges and perspectives in developing new medical technologies for treating Helicobacter pylori without drugs.

Epidemiology of Gastric Intestinal Metaplasia and Gastric Cancer

Gastric cancer remains one of the most common cancers globally. The pathogenesis of intestinal-type gastric cancer involves pre-malignant stages, including gastric intestinal metaplasia (GIM), the replacement of native gastric foveolar and/or glandular epithelium by intestinal-type epithelium. GIM prevalence is highly variable based on geography and race/ethnicity partly due to the varying prevalence of H. pylori, a potent risk factor. However, gastric cancer incidence does not mirror that of H. pylori, demonstrating a complex interaction between H. pylori and risk factors. We will discuss the epidemiology of GIM and gastric cancer, including incidence trends, risk factors, and implications for future management.

Helicobacter pylori Infection: Current Status and Future Prospects on Diagnostic, Therapeutic and Control Challenges

Helicobacter pylori (H. pylori) infection, which affects approximately half of the world's population, remains a serious public health problem. As H. pylori infection leads to a number of gastric pathologies, including inflammation, gastroduodenal ulcers, and malignancies, early detection and treatment are crucial to preventing the spread of the infection. Multiple extragastric complications, such as iron deficiency anaemia, immune thrombocytopenic purpura, vitamin B12 deficiency, diabetes mellitus, cardiovascular diseases, and certain neurological disorders, have also been linked to H. pylori infection. An awareness of H. pylori and associated health hazards is necessary to minimize or even eradicate the infection. Therefore, there is an urgent need to raise the standards for the currently employed diagnostic, eradication, alternative treatment strategies. In addition, a brief overview of traditional and cutting-edge approaches that have proven effective in identifying and managing H. pylori is needed. Based on the test and laboratory equipment available and patient clinical characteristics, the optimal diagnostic approach requires weighing several factors. The pathophysiology and pathogenic mechanisms of H. pylori should also be studied, focusing more on the infection-causing virulence factors of this bacterium. Accordingly, this review aims to demonstrate the various diagnostic, pathophysiological, therapeutic, and eradication tactics available for H. pylori, emphasizing both their advantages and disadvantages. Invasive methods (such as quick urease testing, biopsy, or culture) or noninvasive methods (such as breath tests, stool investigations, or serological tests) can be used. We also present the most recent worldwide recommendations along with scientific evidence for treating H. pylori. In addition to the current antibiotic regimens, alternative therapies may also be considered. It is imperative to eradicate the infections caused by H. pylori as soon as possible to prevent problems and the development of stomach cancer. In conclusion, significant advances have been made in identifying and treating H. pylori. To improve eradication rates, peptide mass fingerprinting can be used as a diagnostic tool, and vaccines can also eliminate the infection.

Application of a WeChat-based mini-app as a patient reminder in Helicobacter pylori eradication: a prospective multi-center randomized controlled study

BACKGROUND

To improve the eradication rate of H. pylori, researchers have investigated the role of WeChat-based mini-app as an electronic reminding system in H. pylori treatment.

METHODS

Subjects from three medical centers were divided into two groups. Patients in the daily mini-app-based notification system group received daily notifications via the WeChat mini-app. Patients in the control group received one-time verbal education on the first clinical visit. Both groups received a 14-day quadruple therapy to eradicate H. pylori infection. Eradication rate, compliance, adverse events and satisfaction were evaluated.

RESULTS

Both intention-to-treat (ITT) and per-protocol (PP) analyses were conducted. The eradication rate in the daily mini-app-based notification system group was slightly higher compared with the control group (ITT analysis: 76.70% vs. 70.73%, p = 0.312; PP analysis: 85.87% vs. 82.86%, p = 0.562). The compliance was significantly higher in the daily mini-app-based notification system group (ITT analysis: 85.52% vs. 70.48%, p = 0.028; PP analysis: 92.39% vs. 81.90%, p = 0.030). The adverse event rates were similar between the two groups (PP analysis: 36.96% vs. 40.95%, p = 0.566). No significant difference in eradication rate was seen in each subgroup analysis by age, place of residence, grade of education, or endoscopic findings.

CONCLUSION

The study showed that daily mini-app-based notification improved patient compliance but not H. pylori eradication rate. Trial registration The research was registered in the Chinese Clinical Trial Registry (ChiCTR2000031011, 21/03/2020).

Recombinant Helicobacter pylori Vaccine Delivery Vehicle: A Promising Tool to Treat Infections and Combat Antimicrobial Resistance

Antimicrobial resistance (AMR) has become a global public health threat. Experts agree that unless proper actions are taken, the number of deaths due to AMR will increase. Many strategies are being pursued to tackle AMR, one of the most important being the development of efficient vaccines. Similar to other bacterial pathogens, AMR in Helicobacter pylori (Hp) is rising worldwide. Hp infects half of the human population and its prevalence ranges from <10% in developed countries to up to 90% in low-income countries. Currently, there is no vaccine available for Hp. This review provides a brief summary of the use of antibiotic-based treatment for Hp infection and its related AMR problems together with a brief description of the status of vaccine development for Hp. It is mainly dedicated to genetic tools and strategies that can be used to develop an oral recombinant Hp vaccine delivery platform that is (i) completely attenuated, (ii) can survive, synthesize in situ and deliver antigens, DNA vaccines, and adjuvants to antigen-presenting cells at the gastric mucosa, and (iii) possibly activate desired compartments of the gut-associated mucosal immune system. Recombinant Hp vaccine delivery vehicles can be used for therapeutic or prophylactic vaccination for Hp and other microbial pathogens.

Helicobacter pyloril-asparaginase: a study of immunogenicity from an in silico approach

Helicobacter pylori has become the causal agent of multiple forms of gastric disease worldwide, including gastric cancer. The enzyme l-asparaginase (ASNase) has been studied as a virulence factor. In this work, we performed an in silico investigation to characterize the immunological profile of H. pylori ASNase (HpASNase) to ascertain the possible implication of HpASNase immunogenicity in the H. pylori virulence mechanism. We applied a workflow based on bioinformatics tools, which, by calculating the relative frequency of immunogenic T-cell and B-cell epitopes, allowed us to predict the immunogenicity and allergenicity of HpASNase in silico. We also visualized the epitopes by mapping them into the native structure of the enzyme. We report for the first time the T-cell and B-cell epitope composition that contributes to the immunogenicity of this HpASNase, as well as the regions that could generate a hypersensitivity response in humans. ASNase from H. pylori resulted in highly immunogenic and allergenic. The high immunogenicity of HpASNase could imply the pathogenic mechanisms of H. pylori. This knowledge could be important for the development of new drugs against H. pylori infections.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03359-0.

Current and Future Perspectives in the Diagnosis and Management of Helicobacter pylori Infection

Helicobacter pylori (Hp) is a prevalent organism infecting almost half the global population. It is a significant concern, given its associated risk of gastric cancer, which is the third leading cause of cancer death globally. Infection can be asymptomatic or present with dyspeptic symptoms. It may also present with alarm symptoms in the case of progression to cancer. Diagnosis can be achieved non-invasively (breath tests, stool studies, or serology) or invasively (rapid urease test, biopsy, or culture). Treatment involves acid suppression and regimens containing several antibiotics and is guided by resistance rates. Eradication is essential, as it lowers the risk of complications and progression to cancer. Follow-up after eradication is similarly important, as the risk of cancer progression remains. There have been many recent advances in both diagnosis and treatment of Hp. In particular, biosensors may be effective diagnostic tools, and nanotechnology, vaccines, and potassium-competitive acid blockers may prove effective in enhancing eradication rates.

Management of Helicobacter pylori infection: the Maastricht VI/Florence consensus report

Helicobacter pyloriInfection is formally recognised as an infectious disease, an entity that is now included in the International Classification of Diseases 11th Revision. This in principle leads to the recommendation that all infected patients should receive treatment. In the context of the wide clinical spectrum associated with Helicobacter pylori gastritis, specific issues persist and require regular updates for optimised management.The identification of distinct clinical scenarios, proper testing and adoption of effective strategies for prevention of gastric cancer and other complications are addressed. H. pylori treatment is challenged by the continuously rising antibiotic resistance and demands for susceptibility testing with consideration of novel molecular technologies and careful selection of first line and rescue therapies. The role of H. pylori and antibiotic therapies and their impact on the gut microbiota are also considered.Progress made in the management of H. pylori infection is covered in the present sixth edition of the Maastricht/Florence 2021 Consensus Report, key aspects related to the clinical role of H. pylori infection were re-evaluated and updated. Forty-one experts from 29 countries representing a global community, examined the new data related to H. pylori infection in five working groups: (1) indications/associations, (2) diagnosis, (3) treatment, (4) prevention/gastric cancer and (5) H. pylori and the gut microbiota. The results of the individual working groups were presented for a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in various clinical fields.

Gastric organoids: Advancing the study of H. pylori pathogenesis and inflammation

For decades, traditional in vitro and in vivo models used for the study of Helicobacter pylori infection have relied heavily on the use of gastric cancer cell lines and rodents. Major challenges faced by these methods have been the inability to study cancer initiation in already cancerous cell lines, and the difficulty in translating results obtained in animal models due to genetic differences. These challenges have prevented a thorough understanding of the pathogenesis of disease and slowed the development of cancer therapies and a suitable vaccine against the pathogen. In recent years, the development of gastric organoids has provided great advantages over the traditional in vivo and in vitro models due to their similarities to the human stomach in vivo, their ease of use, and the capacity for long-term culture. This review discusses the advantages and limitations of existing in vivo and in vitro models of H. pylori infection, and how gastric organoids have been applied to study H. pylori pathogenesis, with a focus on how the pathogen interacts with the gastric epithelium, inflammatory processes, epithelial repair, and cancer initiation. The potential applications of organoids to address more complex questions on the role of hormones, vaccine-induced immunity are also discussed.

Modern knowledge on pathogenesis, diagnosis and treatment of helicobacter infection

Since its discovery, H. pylori infection is known as one of the risk factor for the development of gastritis, peptic ulcer, GIT tumors and numerous other diseases such as psoriasis. Infection caused by H. pylori is posed as the top oncogene in the risk of the development of gastrocarcinoma (First class oncogene by Classification of International Agency for Research of Cancer). That is why the elaboration of fast and accurate methods of diagnosis (non-invasive methods especially) and proper treatment of Helicobacter infection is still very important. Throughout the time, knowledge about pathogenesis of Helicobacter infection have been expanded with the detection of adhesins, chemotaxins and multiple virulence factors related to invasion, adhesion and cytotoxicity of H. pylori. Invasive and non-invasive methods of diagnostics are currently being improved in effectiveness and accuracy. But still, due to different factors (e. g., dramatically increasing drug resistance), eradication of H. pylori remains big problem world-wide. Our review represents modern data on pathogenesis, diagnostics and treatment of Helicobacter infection.

An Overview of Helicobacter pylori Survival Tactics in the Hostile Human Stomach Environment

Helicobacter pylori is well established as a causative agent for gastritis, peptic ulcer, and gastric cancer. Armed with various inimitable virulence factors, this Gram-negative bacterium is one of few microorganisms that is capable of circumventing the harsh environment of the stomach. The unique spiral structure, flagella, and outer membrane proteins accelerate H. pylori movement within the viscous gastric mucosal layers while facilitating its attachment to the epithelial cells. Furthermore, secretion of urease from H. pylori eases the acidic pH within the stomach, thus creating a niche for bacteria survival and replication. Upon gaining a foothold in the gastric epithelial lining, bacterial protein CagA is injected into host cells through a type IV secretion system (T4SS), which together with VacA, damage the gastric epithelial cells. H. pylori does not only establishes colonization in the stomach, but also manipulates the host immune system to permit long-term persistence. Prolonged H. pylori infection causes chronic inflammation that precedes gastric cancer. The current review provides a brief outlook on H. pylori survival tactics, bacterial-host interaction and their importance in therapeutic intervention as well as vaccine development.

Probiotics as the live microscopic fighters against Helicobacter pylori gastric infections

BACKGROUND

Helicobacter pylori (H. pylori) is the causative agent of stomach diseases such as duodenal ulcer and gastric cancer, in this regard incomplete eradication of this bacterium has become to a serious concern. Probiotics are a group of the beneficial bacteria which increase the cure rate of H. pylori infections through various mechanisms such as competitive inhibition, co-aggregation ability, enhancing mucus production, production of bacteriocins, and modulating immune response.

RESULT

In this study, according to the received articles, the anti-H. pylori activities of probiotics were reviewed. Based on studies, administration of standard antibiotic therapy combined with probiotics plays an important role in the effective treatment of H. pylori infection. According to the literature, Lactobacillus casei, Lactobacillus reuteri, Lactobacillus rhamnosus GG, and Saccharomyces boulardii can effectively eradicate H. pylori infection. Our results showed that in addition to decrease gastrointestinal symptoms, probiotics can reduce the side effects of antibiotics (especially diarrhea) by altering the intestinal microbiome.

CONCLUSION

Nevertheless, antagonist activities of probiotics are H. pylori strain-specific. In general, these bacteria can be used for therapeutic purposes such as adjuvant therapy, drug-delivery system, as well as enhancing immune system against H. pylori infection.

DNA vaccine containing Flagellin A gene induces significant immune responses against Helicobacter pylori infection: An in vivo study

Objective(s):

Helicobacter pylori is one of the most prevalent human infectious agents that is directly involved in various upper digestive tract diseases. Although antibiotics-based therapy and proton pump inhibitors eradicate the bacteria mostly, their effectiveness has been declined recently due to emergence of antibiotic-resistant strains. Development of a DNA vaccine is a promising approach against bacterial pathogens. Genes encoding motility factors are promising immunogens to develop a DNA vaccine against H. pylori infection due to critical role of these genes in bacterial attachment and colonization within the gastric lumen. The present study aimed to synthesize a DNA vaccine construct based on the Flagellin A gene (flaA), the predominant flagellin subunit in H. pylori flagella.

Materials and Methods:

The coding sequence of flaA was amplified through PCR and sub-cloned in the pBudCE4.1 vector. The recombinant vector was introduced into the human dermal fibroblast cells, and its potency to express the flaA protein was analyzed using SDS-PAGE. The recombinant construct was intramuscularly (IM) injected into the mice, and the profiles of cytokines and immunoglobulins were measured using ELISA.

Results:

It has been found that flaA was successfully expressed in cells. Recombinant-vector also increased the serum levels of evaluated cytokines and immunoglobulins in mice.

Conclusion:

These findings showed that the pBudCE4.1-flaA construct was able to activate the immune responses. This study is the first step towards synthesis of recombinant-construct based on the flaA gene. Immunization with such construct may inhibit the H. pylori-associated infection; however, further experiments are urgent.

Helicobacter pylori infection: from standard to alternative treatment strategies

Helicobacter pylori is the major component of the gastric microbiome of infected individuals and one of the aetiological factors of chronic gastritis, peptic ulcer disease and gastric cancer. The increasing resistance to antibiotics worldwide has made the treatment of H. pylori infection a challenge. As a way to overhaul the efficacy of currently used H. pylori antibiotic-based eradication therapies, alternative treatment strategies are being devised. These include probiotics and prebiotics as adjuvants in H. pylori treatment, antimicrobial peptides as alternatives to antibiotics, photodynamic therapy ingestible devices, microparticles and nanoparticles applied as drug delivery systems, vaccines, natural products, and phage therapy. This review provides an updated synopsis of these emerging H. pylori control strategies and discusses the advantages, hurdles, and challenges associated with their development and implementation. An effective human vaccine would be a major achievement although, until now, projects regarding vaccine development have failed or were discontinued. Numerous natural products have demonstrated anti-H. pylori activity, mostly in vitro, but further clinical studies are needed to fully disclose their role in H. pylori eradication. Finally, phage therapy has the potential to emerge as a valid alternative, but major challenges remain, namely the isolation of more H. pylori strictly virulent bacterio(phages).

Designing and development of epitope-based vaccines against Helicobacter pylori

Helicobacter pylori infection is the principal cause of serious diseases (e.g. gastric cancer and peptic ulcers). Antibiotic therapy is an inadequate strategy in H. pylori eradication because of which vaccination is an inevitable approach. Despite the presence of countless vaccine candidates, current vaccines in clinical trials have performed with poor efficacy which makes vaccination extremely challenging. Remarkable advancements in immunology and pathogenic biology have provided an appropriate opportunity to develop various epitope-based vaccines. The fusion of proper antigens involved in different aspects of H. pylori colonization and pathogenesis as well as peptide linkers and built-in adjuvants results in producing epitope-based vaccines with excellent therapeutic efficacy and negligible adverse effects. Difficulties of the in vitro culture of H. pylori, high genetic variation, and unfavourable immune responses against feeble epitopes in the complete antigen are major drawbacks of current vaccine strategies that epitope-based vaccines may overcome. Besides decreasing the biohazard risk, designing precise formulations, saving time and cost, and induction of maximum immunity with minimum adverse effects are the advantages of epitope-based vaccines. The present article is a comprehensive review of strategies for designing and developing epitope-based vaccines to provide insights into the innovative vaccination against H. pylori.

Recent chemical syntheses of bacteria related oligosaccharides using modern expeditious approaches

Apart from some essential and crucial roles in life processes carbohydrates also are involved in a few detrimental courses of action related to human health, like infections by pathogenic microbes, cancer metastasis, transplanted tissue rejection, etc. Regarding management of pathogenesis by microbes, keeping in mind of multi drug-resistant bacteria and epidemic or endemic incidents, preventive measure by vaccination is the best pathway as also recommended by the WHO; by vaccination, eradication of bacterial diseases is also possible. Although some valid vaccines based on attenuated bacterial cells or isolated pure polysaccharide-antigens or the corresponding conjugates thereof are available in the market for prevention of several bacterial diseases, but these are not devoid of some disadvantages also. In order to develop improved conjugate T-cell dependent vaccines oligosaccharides related to bacterial antigens are synthesized and converted to the corresponding carrier protein conjugates. Marketed Cuban Quimi-Hib is such a vaccine being used since 2004 to resist Haemophilus influenza b infections. During nearly the past two decades research is going on worldwide for improved synthesis of bacteria related oligosaccharides or polysaccharides towards development of such semisynthetic or synthetic glycoconjugate vaccines. The present dissertation is an endeavour to encompass the recent syntheses of several pathogenic bacterial oligosaccharides or polysaccharides, made during the past ten-eleven years with special reference to modern expeditious syntheses.

Clinical Relevance of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) is a Gram-negative helical, microaerophilic bacterium which colonizes the antrum and body of the stomach, surviving in its harsh environment through mechanisms of acid resistance and colonization factors. It infects approximately 50% of the world population. Although the prevalence of this infection varies from country to country, as well as between different ethnic, social or age groups, it is estimated that about 50% of the human population only carries this microorganism. While H. pylori has been found to play a major etiological and pathogenic role in chronic gastritis, peptic ulcer disease and gastric cancer, its importance for many types of extra-gastric disease needs to be further investigated. The choice of tests to diagnose H. pylori infection, defined as invasive or non-invasive, depends on the clinical indication as to whether to perform upper gastrointestinal endoscopy. Focusing on bacterial eradication, the treatment should be decided locally based on the use of antibiotics and documented antibiotic resistance. The author provides an overview of the current state of knowledge about the clinical aspects of H. pylori infection, especially its diagnostic and therapeutic management.

Vaccine development against Helicobacter pylori: from ideal antigens to the current landscape

Introduction: The interest of the world scientific community for an effective vaccine against Helicobacter pylori infection arises from its high prevalence and association with many diseases. Moreover, with an immunological response that is not always effective for the eradication of the bacteria and an increasing antibiotic resistance in the treatment of this infection, the search for a vaccine and new therapeutic modalities to control this infection is urgent.Areas covered: We bring an overview of the infection worldwide, discussing its prevalence, increasing resistance to antibiotics used in its therapy, in addition to the response of the immune system to the infection registered so far. Moreover, we address the most used antigens and their respective immunological responses expected or registered up to now. Finally, we address the trials and their partial results in development for such vaccines.Expert opinion: Although several studies for the development of an effective vaccine against this pathogen are taking place, many are still in the preclinical phase or even without updated information. In this sense, taking into account the high prevalence and association with important comorbidities, the interest of the pharmaceutical industry in developing an effective vaccine against this pathogen is questioned.

Helicobacter urease suppresses cytotoxic CD8 + T cell responses through activating Myh9-dependent induction of PD-L1

As a key virulence factor for persistent colonization, Urease B subunit (UreB) is considered to be an ideal vaccine antigen against Helicobacter pylori (H. pylori) infection. However, the role and molecular mechanisms of UreB involved in immune microenvironment dysregulation still remains largely unknown. In the present study, we evaluated the effects of UreB on macrophage activation and found that UreB induced PD-L1 accumulation on Bone marrow-derived macrophages (BMDMs). Co-culture assays further revealed that UreB-induced PD-L1 expression on BMDMs significantly decreased the proliferation and secretion of cytolytic molecules (granzyme B and perforin) of splenic CD8 + T cells isolated from inactivated H. pylori-immunized mice. More importantly, myosin heavy chain 9 (Myh9) was confirmed to be a direct membrane receptor of UreB via using LC-MS/MS and Co-immunoprecipitation and required for PD-L1 upregulation on BMDMs. Molecular studies further demonstrated that the interaction between UreB and Myh9 decreased GCN2 autophosphorylation and enhanced intracellular pool of amino acids, leading to the upregulation of S6K phosphorylation, a commonly used marker for monitoring activation of mTORC1 signaling activity. Furthermore, blocking mTORC1 activation with its inhibitor Temsirolimus reversed UreB-induced PD-L1 upregulation and the subsequently inhibitory effects of BMDMs on activation of cytotoxic CD8 + T cell responses. Overall, our data unveil a novel immunosuppressive mechanism of UreB during H. pylori infection, which may provide valuable clue for the optimization of H. pylori vaccine.

Isolation Method and Characterization of Outer Membranes Vesicles of Helicobacter pylori Grown in a Chemically Defined Medium

Outer membrane vesicles (OMVs) are small vesicles constitutively shed by all Gram-negative bacterium, which have been proposed to play a role in Helicobacter pylori persistence and pathogenesis. The methods currently available for the isolation of H. pylori OMVs are diverse and time-consuming, raising the need for a protocol standardization, which was the main aim of this study. Here, we showed that the chemically defined F12 medium, supplemented with cholesterol, nutritionally supports bacterial growth and maintains H. pylori viability for at least 72 h. Additionally, we developed an abridged protocol for isolation of OMVs from these bacterial cultures, which comprises a low-speed centrifugation, supernatant filtration through a 0.45 μm pore, and two ultracentrifugations for OMVs’ recovery and washing. Using this approach, a good yield of highly pure bona fide OMVs was recovered from cultures of different H. pylori strains and in different periods of bacterial growth, as assessed by nanoparticle tracking analysis, transmission electron microscopy (TEM), and proteomic analyses, confirming the reliability of the protocol. Analysis of the proteome of OMVs isolated from H. pylori F12-cholesterol cultures at different time points of bacterial growth revealed differentially expressed proteins, including the vacuolating cytotoxin VacA. In conclusion, this work proposes a time- and cost-efficient protocol for the isolation of H. pylori OMVs from a chemically defined culture medium that is suitable for implementation in research and in the biopharmaceutical field.

The relationship between gastrointestinal cancers and the microbiota

The contribution of the microbiota to disease progression and treatment efficacy is often neglected when determining who is at the highest risk of developing gastrointestinal cancers or designing treatment strategies for patients. We reviewed the current literature on the effect of the human microbiota on cancer risk, prognosis, and treatment efficacy. We highlight emerging research that seeks to identify microbial signatures as biomarkers for various gastrointestinal cancers, and discuss how we could harness knowledge of the microbiome to detect, prevent, and treat these cancers. Finally, we outline further research needed in the field of gastrointestinal cancers and the microbiota, and describe the efforts required to increase the accuracy and reproducibility of data linking the microbiome to cancer.

Smarter cures to combat COVID-19 and future pathogens: a review

Prevention is better than cure. A milestone of the anthropocene is the emergence of a series of epidemics and pandemics often characterized by the transmission of a pathogen from animals to human in the past two decades. In particular, the coronavirus disease 2019 (COVID-19) has made a profound impact on emergency responding and policy-making in a public health crisis. Classical solutions for controlling the virus, such as travel restrictions, lockdowns, repurposed drugs and vaccines, are socially unpopular and medically limited by the fast mutation and adaptation of the virus. This is exacerbated by microbial resistance to therapeutic drugs and the slowness of vaccine development. In other words, microbial pathogens are somehow 'smarter' and faster than us, thus calling for more intelligent cures to combat future pandemics. Here, we compare therapeutics for COVID-19 such as synthetic drugs, vaccines, antibodies and phages. We present the strength and limitations of antibiotic and antiviral drugs, vaccines, and antibody-based therapeutics. We describe smarter, cheaper and preventive cures such as bacteriophages, food medicine using probiotics and prebiotics, sports, healthy diet, music, yoga, Tai Chi, dance, reading, knitting, cooking and outdoor activities. Some of these preventive cures have been intuitively developed since thousands of years ago, as illustrated by the fascinating similarity of the Chinese characters for 'music' and 'herbal medicine.'