Oral administration of recombinant<i>Neisseria meningitidis</i>PorA genetically fused to<i>H. pylori</i>HpaA antigen increases antibody levels in mouse serum, suggesting that PorA behaves as a putative adjuvant

Background: The clinical result severity of Helicobacter pylori infection is determined by a combination of environmental factors, host genetic background, and H. pylori virulence factors. A number of genes containing vacA, iceA, babA2, cagA, cagE, hsp60-70, and hpa have been identified to enhance H. pylori pathogenicity by encoding virulent proteins. The babA and hpa proteins are considered 2 major adhesion molecules, and thus they are key agents in the initial step of H. pylori invasion. Objectives: This study aimed at investigating the existence of babA2 and hpa virulence factors of H. pylori in Iranian patients with gastrointestinal complications. The relationship between these agents and clinical results was also investigated. Methods: A total of 80 positive biopsies out of 156 samples were studied to determine babA2 and hpa gene frequency by PCR. The positive biopsies were collected from patients suffering from gastric cancer (n =18), peptic ulcer (n = 26), and gastritis (n =36). Results:The babA2+ strains were found in 51 (64%) patients and the hpa+ strains in 57 (71%) patients were associated with sex (P = 0.02). However, the frequency of these factors was not significant between gastric disease groups (P > 0.05). Conclusions: Our results revealed different frequency of these virulence factors in Iran, which emphasized the effects of geographical influences. Also, it was found that male patients had higher rate of hpa than females, highlighting the gender specific factors.

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“…Furthermore, this protein is a promising vaccine candidate against H. pylori infection (17). Hpa is a strong colonization factor for H. pylori.…”

Section: Discussionmentioning

confidence: 99%

The Prevalence of Helicobacter pylori Virulence Related Genes (hpa and babA2) in Iranian Patients with Gastrointestinal Disorders

Heidari

Nezhad

Noroozi

et al. 2017

Jundishapur J Microbiol

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“…PorA is an outer membrane protein (OMP) from the Neisseria meningitidis [ 56 ]. It is remarkable that PorA has an important feature of oral protein adjuvants, namely resistance to proteolytic enzymes in the GIT [ 57 ]. It has the potential to act as an oral adjuvant when conjugated to antigens.…”

Section: Biogenic Type Oral Vaccine Adjuvantsmentioning

confidence: 99%

“…It has the potential to act as an oral adjuvant when conjugated to antigens. For example, when PorA was fused with the H. pylori HpaA antigen and expressed in Lactococcus lactis , PorA could significantly enhance the antibody response against the HpaA antigen after oral administration in mice [ 57 ].…”

Section: Biogenic Type Oral Vaccine Adjuvantsmentioning

confidence: 99%

Current Progress and Challenges in the Study of Adjuvants for Oral Vaccines

Yang

et al. 2023

BioDrugs

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Over the past 20 years, a variety of potential adjuvants have been studied to enhance the effect of oral vaccines in the intestinal mucosal immune system; however, no licensed adjuvant for clinical application in oral vaccines is available. In this review, we systematically updated the research progress of oral vaccine adjuvants over the past 2 decades, including biogenic adjuvants, non-biogenic adjuvants, and their multi-type composite adjuvant materials, and introduced their immune mechanisms of adjuvanticity, aiming at providing theoretical basis for developing feasible and effective adjuvants for oral vaccines. Based on these insights, we briefly discussed the challenges in the development of oral vaccine adjuvants and prospects for their future development.

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“…Other bacterial proteins and messengers have been explored as LAB adjuvants. These include: Muramyl dipeptide, Neisseria meningitidis PorA, c-di-AMP, and Salmonella resistance to complement killing [102][103][104][105]. Addition of these adjuvants to LAB mucosal vaccines resulted in an increased immune response and/or protection to challenge.…”

Section: Additional Bacterial Derived Adjuvantsmentioning

confidence: 99%

“…This protein is immunodominant and, while using this protein as a vaccine antigen against N. meningitidis has not been successful, it has the potential to act as an adjuvant when conjugated to an antigen. For example, PorA increased the immune response to HpaA antigen from Helicobacter pylori [103]. The exact mechanism of action of PorA is still under investigation.…”

Section: Additional Bacterial Derived Adjuvantsmentioning

confidence: 99%

Adjuvant Strategies for Lactic Acid Bacterial Mucosal Vaccines

Vilander

Dean

2019

Vaccines

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Lactic acid bacteria (LAB) are Gram-positive, acid-tolerant bacteria that have long been used in food fermentation and are generally recognized as safe (GRAS). LAB are a part of a normal microbiome and act as probiotics, improving the gastrointestinal microbiome and health when consumed. An increasing body of research has shown the importance of the microbiome on both mucosal immune heath and immune response to pathogens and oral vaccines. Currently, there are few approved mucosal vaccines, and most are attenuated viruses or bacteria, which necessitates cold chain, carries the risk of reversion to virulence, and can have limited efficacy in individuals with poor mucosal health. On account of these limitations, new types of mucosal vaccine vectors are necessary. There has been increasing interest and success in developing recombinant LAB as next generation mucosal vaccine vectors due to their natural acid and bile resistance, stability at room temperature, endogenous activation of innate and adaptive immune responses, and the development of molecular techniques that allow for manipulation of their genomes. To enhance the immunogenicity of these LAB vaccines, numerous adjuvant strategies have been successfully employed. Here, we review these adjuvant strategies and their mechanisms of action which include: Toll-like receptor ligands, secretion of bacterial toxins, secretion of cytokines, direct delivery to antigen presenting cells, and enterocyte targeting. The ability to increase the immune response to LAB vaccines gives them the potential to be powerful mucosal vaccine vectors against mucosal pathogens.

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Oral administration of recombinantNeisseria meningitidisPorA genetically fused toH. pyloriHpaA antigen increases antibody levels in mouse serum, suggesting that PorA behaves as a putative adjuvant

Cited by 6 publications

References 79 publications

The Prevalence of Helicobacter pylori Virulence Related Genes (hpa and babA2) in Iranian Patients with Gastrointestinal Disorders

The Prevalence of Helicobacter pylori Virulence Related Genes (hpa and babA2) in Iranian Patients with Gastrointestinal Disorders

Current Progress and Challenges in the Study of Adjuvants for Oral Vaccines

Adjuvant Strategies for Lactic Acid Bacterial Mucosal Vaccines

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