Moving Helicobacter pylori vaccine development forward with bioinformatics and immunomics

Reverse engineering approach: a step towards a new era of vaccinology with special reference to Salmonella

INTRODUCTION

Salmonella is responsible for causing enteric fever, septicemia, and gastroenteritis in humans. Due to high disease burden and emergence of multi- and extensively drug-resistant Salmonella strains, it is becoming difficult to treat the infection with existing battery of antibiotics as we are not able to discover newer antibiotics at the same pace at which the pathogens are acquiring resistance. Though vaccines against Salmonella are available commercially, they have limited efficacy. Advancements in genome sequencing technologies and immunoinformatics approaches have solved the problem significantly by giving rise to a new era of vaccine designing, i.e. 'Reverse engineering.' Reverse engineering/vaccinology has expedited the vaccine identification process. Using this approach, multiple potential proteins/epitopes can be identified and constructed as a single entity to tackle enteric fever.

AREAS COVERED

This review provides details of reverse engineering approach and discusses various protein and epitope-based vaccine candidates identified using this approach against typhoidal Salmonella.

EXPERT OPINION

Reverse engineering approach holds great promise for developing strategies to tackle the pathogen(s) by overcoming the limitations posed by existing vaccines. Progressive advancements in the arena of reverse vaccinology, structural biology, and systems biology combined with an improved understanding of host-pathogen interactions are essential components to design new-generation vaccines.

A survey on chimeric UreB229-561-HpaA protein targeting Helicobacter pylori: Computational and in vitro urease activity valuation

Helicobacter pylori (H. pylori) as microaerophilic, Gram-negative bacterium colonize the human gastric milieu, where it impetuses chronic disorders. Vaccination is a complementary plan, along with antibiotic therapy, for clearance of H. pylori. Today, Computer based tools are essential for the evaluation, design, and experiment for novel chimeric targets for immunological administration. The purpose of this experiment was immunoinformatic analysis of UreB and HpaA molecules in a fusion arrangement and also, construction and expression of recombinant protein containing chimeric sequences. The targets sequences were screened by using of standard in silico tools and immunoinformatic web servers. The high-resolution 3D models of the protein were created and were validated; indeed, the B-and T-cell restricted epitopes were mapped on the chimeric protein. The recombinant protein in frame of the expression vector pET28a were expressed and purified successfully. The urease activity and immunoblotting were performed in vitro condition. This study confirmed that the engineered protein as a highly conserved, hydrophilic, non-allergenic contained remarkable B-cell and T-cell epitopes. It was magnificently attained; chimeric UreB_229-561-HpaA could provoke both humoral and cellular immunity. The immunoblotting was shown that the chimeric protein could be detected by serum of immunized animal and H.pylori positive patients. In this study, several antigenic patches from UreB and HpaA were identified that could be an efficient immune system activator. The in vitro analysis of our chimeric molecule confirmed its urease activity. It also confirmed that the chimeric protein could be detected by serum of immunized animal and H.pylori positive patients.

The use of databases, data mining and immunoinformatics in vaccinology: where are we?

INTRODUCTION

Vaccinology has evolved from a sub-discipline focussed on simplistic vaccine development based on antibody-mediated protection to a separate discipline involving epidemiology, host and pathogen biology, immunology, genomics, proteomics, structure biology, protein engineering, chemical biology, and delivery systems. Data mining in combination with bioinformatics has provided a scaffold linking all these disciplines to the design of vaccines and vaccine adjuvants. Areas covered: This review provides background knowledge on immunological aspects which have been exploited with informatics for the in silico analysis of immune responses and the design of vaccine antigens. Furthermore, the article presents various databases and bioinformatics tools, and discusses B and T cell epitope predictions, antigen design, adjuvant research and systems immunology, highlighting some important examples, and challenges for the future. Expert opinion: Informatics and data mining have not only reduced the time required for experimental immunology, but also contributed to the identification and design of novel vaccine candidates and the determination of biomarkers and pathways of vaccine response. However, more experimental data is required for benchmarking immunoinformatic tools. Nevertheless, developments in immunoinformatics and reverse vaccinology, which are nascent fields, are likely to hasten vaccine discovery, although the path to regulatory approval is likely to remain a necessary impediment.

Immunomics: a 21st century approach to vaccine development for complex pathogens

Immunomics is a relatively new field of research which integrates the disciplines of immunology, genomics, proteomics, transcriptomics and bioinformatics to characterize the host-pathogen interface. Herein, we discuss how rapid advances in molecular immunology, sophisticated tools and molecular databases are facilitating in-depth exploration of the immunome. In our opinion, an immunomics-based approach presides over traditional antigen and vaccine discovery methods that have proved ineffective for highly complex pathogens such as the causative agents of malaria, tuberculosis and schistosomiasis that have evolved genetic and immunological host-parasite adaptations over time. By using an integrative multidisciplinary approach, immunomics offers enormous potential to advance 21st century antigen discovery and rational vaccine design against complex pathogens such as the Plasmodium parasite.

Chinese Helicobacter pylori vaccine: Solution for an old challenge?

Helicobacter pylori (H. pylori) is an important cause for gastric cancer in high risk individuals. H. pylori colonizes more than 50% of the world’s population and associated peptic ulcer disease and gastric malignancy have important public health implications. It has been classified as a class I carcinogen in 1994 by the World Health Organization. Clinicians are often prompted to eliminate the infection the moment it is detected. This also, unfortunately, led to reckless use of antibiotics and reports of increasing resistance are now worldwide. Each year, many of people die from gastric cancer; thus application of effective vaccine can reduce this relatively high mortality worldwide. H. pylori can be eliminated by antibiotics but efficacy is sharply decreasing. Moreover, current therapy is also expensive and with side effects. Vaccine may be the best solution to the above problem but there are many challenges in producing such an effective therapeutic vaccine. Recently, the Chinese group published in Lancet, a single-center, randomized, phase III study of an oral recombinant vaccine (Urease B subunit fused with heat-labile enterotoxin B derived from Escherichia coli) prescribed in the Chinese children (6-15 years) without a history of H. pylori infection. This review provides an insight into this new solution for an old challenge.

Vaccine against Helicobacter pylori: Inevitable approach

Over three decades have passed since the discovery of Helicobacter pylori (H. pylori), and yet many questions about its treatment remain unanswered. For example, there is no certainty regarding continued use of current antibiotic therapy against H. pylori. The bad news is that even combined regimens are also unable to eradicate bacterial colonization. The worst problem with H. pylori chemotherapy is that even if we identify the most successful regimen, it cannot eliminate the risk of re-infection. This problem is further complicated by the fact that clinicians have no information as to whether probiotics are useful or not. Moreover, to date, we have no large scale produced vaccine effective against H. pylori. Due to the relatively rapid and abundant dissemination of guidelines globally reported concerning management of gastric cancer prevention and therapeutic regimens, clinicians may choose a vaccine as better effective weapon against H. pylori. Therefore, a radical shift in adopted strategies is needed to guide ultimate decisions regarding H. pylori management. In light of failures in vaccine projects, we should identify better vaccine design targeting conserved/essential genes. The unique character and persistence of H. pylori pose obstacles to making an effective vaccine. Preferably, in developing countries, the best reasonable and logical approach is to recommend prophylactic H. pylori vaccine among children as an obligatory national program to limit primary colonization. Trying to produce a therapeutic vaccine would be postponed until later. In reality, we should not forget to prescribe narrow spectrum antibiotics. In the current review, I draw a route to define the best adopted strategy against this rogue bacterium.

Immunology and vaccines and nanovaccines for Helicobacter pylori infection

Helicobacter pylori infection is very common worldwide and is an important cause of gastritis, peptic ulcer disease, gastric mucosa-associated lymphoid tissue lymphoma, and gastric adenocarcinoma. Since the eradication requires treatment with multidrug regimens, prevention of primary infection by a suitable vaccine is attractive. Developing vaccines on the spot when and where an infection is breaking out might be possible, thanks to engineered nanoparticles. In this review, the nature of the host immune response to H. pylori infection is considered. We explain recent candidate vaccines and prophylactic or therapeutic immunization strategies for use against H. pylori. We also describe identification of different types of immune responses that may be related to protection against H. pylori infection. Thus, it seems that there is still a strong need to clarify the main protective immune response against H. pylori.