Identification of B-Cell Epitopes of HspA from Helicobacter pylori and Detection of Epitope Antibody Profiles in Naturally Infected Persons.
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ABSTRACT:
SUBMITTER: Zhang X
PROVIDER: S-EPMC8779794 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Antigen-specific CD4+ T cells play an essential role in effective immunity against Helicobacter pylori (H. pylori) infection. Lpp20, a conserved lipoprotein of H. pylori, has been investigated as one of major protective antigens for vaccination strategies. Our previous study identified two H-2d-restricted CD4+ T cell epitopes within Lpp20 and an epitope vaccine based on these epitopes was constructed, which protected mice in prophylactic and therapeutic vaccination against H. pylori infection. Immunodominant CD4+ T cell response is an important feature of antiviral, antibacterial, and antitumor cellular immunity. However, while many immunodominant HLA-restricted CD4+ T cell epitopes of H. pylori protective antigens have been identified, immunodominant HLA-restricted Lpp20 CD4+ T cell epitope has not been elucidated. In this study, a systematic method was used to comprehensively evaluate the immunodominant Lpp20-specific CD4+ T cell response in H. pylori-infected patients. Using in vitro recombinant Lpp20 (rLpp20)-specific expanded T cell lines from H. pylori-infected subjects and 27 18mer overlapping synthetic peptides spanned the whole Lpp20 protein, we have shown that L55-72 and L79-96 harbored dominant epitopes for CD4+ T cell responses. Then the core sequence within these two 18mer dominant epitopes was screened by various extended or truncated 13mer peptides. The immunodominant epitope was mapped to L57-69 and L83-95. Various Epstein-Barr virus (EBV) transformed B lymphoblastoid cell lines (B-LCLs) with different HLA alleles were used as antigen presenting cell (APC) to present peptides to CD4+ T cells. The restriction molecules were determined by HLA class-antibody blocking. L57-69 was restricted by DRB1-1501 and L83-95 by DRB1-1602. The epitopes were recognized on autologous dendritic cells (DCs) loaded with rLpp20 but also those pulsed with whole cell lysates of H. pylori (HP-WCL), suggesting that these epitopes are naturally processed and presented by APC. CD4+ T cells were isolated from H. pylori-infected patients and stimulated with L57-69 and L83-95. These two epitopes were able to stimulate CD4+ T cell proliferation. This study may be of value for the future development of potential H. pylori vaccine.
| S-EPMC5974113 | biostudies-literature
Project description:Helicobacter pylori commonly infects the epithelial layer of the human stomach and in some individuals causes peptic ulcers, gastric adenocarcinoma or gastric lymphoma. Helicobacter pylori is a genetically diverse species, and the most important bacterial virulence factor that increases the risk of developing disease, versus asymptomatic colonization, is the cytotoxin associated gene pathogenicity island (cagPAI). Socially housed rhesus macaques are often naturally infected with H. pylori similar to that which colonizes humans, but little is known about the cagPAI. Here we show that H. pylori strains isolated from naturally infected rhesus macaques have a cagPAI very similar to that found in human clinical isolates, and like human isolates, it encodes a functional type IV secretion system. These results provide further support for the relevance of rhesus macaques as a valid experimental model for H. pylori infection in humans.
| S-EPMC5975239 | biostudies-literature
Project description:BackgroundHelicobacter pylori (HP) is a causative factor for several gastrointestinal diseases. A HP seropositive antibody titer (i.e., ≥10 U/mL), a threshold indicating an HP infection, is known to be associated with changes in lipid metabolism. There is evidence that HP infection can be found in some individuals with HP antibody titer of between 3 and 9.9 U/mL (termed as "negative-high titer"). However, it is unknown about the relationship between HP negative-high titer and lipid metabolism. The present study aimed to quantify the association between HP negative-high antibody titer and lipid profiles.Materials and methodsWe surveyed 2,478 people who underwent a Ningen Dock examination and had serological HP antibody data, from May 2016 to December 2020 at National Center for Global Health and Medicine, Tokyo, Japan. Multiple regression models were used to quantify the association between HP antibody titer and serum lipid levels.ResultsThe adjusted odds ratio (95% confidence interval [CI]) for dyslipidemia in HP negative-high and positive titer was 1.24 (0.96, 1.79) and 1.36 (1.10, 1.68), respectively, compared with HP negative-low titer; p trend =0.005. The adjusted mean (95% CI) of high-density lipoprotein cholesterol (HDL-C) in HP negative-low, negative-high, and positive titer was 58.78 (57.86-59.71), 55.30 (53.70-56.91), and 53.76 (52.90-54.63) mg/dL, respectively; p trend <0.001. Higher HP antibody titers were also associated with higher ratio of low-density lipoprotein cholesterol (LDL-C) to HDL-C, but not triglycerides, or total cholesterols.ConclusionThe present cross-sectional study suggests that a HP negative-high antibody titer may be associated with dyslipidemia, HDL-C, and LDL-C to HDL-C ratio among Japanese Ningen Dock's participants.
| S-EPMC9398768 | biostudies-literature
Project description:AIM:To construct a recombinant vector which can express outer membrane protein (OMP) with M(r)18,000 and heat shock protein A (HspA) from Helicobacter pylori (H. pylori) in E. coli BL21, and to exploit the possibility for obtaining the vaccine conferring protection from H. pylori infection. METHODS:The target gene of HspA was amplified from H. pylori chromosome by PCR, and then inserted into the prokaryotic expression vector pET32a (+) by restrictive endonuclease enzyme kpn I, BamH I simultaneously. The recombinant vector was used to sequence, and then together with pET32a (+)/Omp(18), digested by restrictive endonuclease enzyme Hind III and BamH I simultaneously. pET32a(+)/HspA and Omp(18) were recovered from 1 % agarose gel by gel kit, and ligated with T(4) ligase by BamH I digested viscidity end. The recombinant plasmid of pET32a(+)/HspA/Omp(18) was transformed and expressed in E. coli BL21 (DE3) under induction of IPTG. After purification, its antigenicity of the fusion protein was detected by Western blot. RESULTS:Enzyme digestion analysis and sequencing showed that the target genes were inserted into the recombinant vector, composed of 891 base pairs, encoded objective polypeptides of 297 amino acid residues. Compared with GenBank reported by Tomb et al, there were 1.3 % and 1.4 % differences in obtained H. pylori nucleotide sequence and amino acid residues, respectively. SDS-PAGE analysis showed that relative molecule mass (M(r)) of the expressed product was M(r) 51,000, M(r) of protein expressed by pET32a (+) was about M(r) 20,000, and soluble expression product accounted for 18.96 % of total bacterial protein. After purification with Ni(+2)-NTA agarose resins, the purification of recombinant fusion protein was about 95 %. Western blot showed that recombinant fusion protein could be recognized by the patients' serum infected with H. pylori and anti-Omp(18) monoclone, suggesting that this protein had good antigenicity. CONCLUSION:The gene coding for H. pylori M(r)18,000 OMP and HspA was cloned and expressed successfully. The results obtained lay the foundation for development of H. pylori protein vaccine and a quick diagnostic kit.
| S-EPMC4611538 | biostudies-literature
Project description:Aim. The aim of this study was to develop an oral Lactococcus lactis (L. lactis) vaccine against Helicobacter pylori (H. pylori). Methods. After L. lactis NZ3900/pNZ8110-hspA was constructed, growth curves were plotted to study whether the growth of recombinant L. lactis was affected after hspA was cloned into L. lactis and whether the growth of empty bacteria, empty plasmid bacteria, and recombinant L. lactis was affected by different concentrations of Nisin; SDS-PAGE and Western blot were adopted, respectively, to detect the HspA expressed by recombinant L. lactis and its immunoreactivity. Results. There was no effect observed from the growth curve after exogenous gene hspA was cloned into L. lactis NZ3900; different concentrations of Nisin did not affect the growth of NZ3900 and NZ3900/pNZ8110, while different concentrations of Nisin inhibited the growth of NZ3900/pNZ8110-hspA except 10 ng/mL Nisin. No HspA strip was observed from SDS-PAGE. Western blot analysis showed that HspA expressed by recombinant bacteria had favorable immunoreactivity. Conclusion. The growth of recombinant L. lactis was suppressed even though a small amount of HspA had been induced to express. Therefore recombinant L. lactis only express HspA which was not suitable to be oral vaccine against Helicobacter pylori.
| S-EPMC4421100 | biostudies-literature
Project description:OBJECTIVES:Helicobacter pylori are among most common human pathogens affecting at least half of the world's population. Mobility is one of the important primary factors in bacterial colonization and invasion. The purpose of this research is cloning, expression, and purification of FlaA protein specific epitopes in order to evaluate their antigenicity and immunogenicity. MATERIALS AND METHODS:The antigenic region of the flaA gene was bioinformatically predicted using Epitope mapping software's and the predicted epitopes were expressed in a prokaryotic expression vector. The antigen was injected into the animal model (mice BALB/c) and some indicators including IgG1, IgG2a, IgA, IFN-γ, and IL 5 were measured. RESULTS:The immunogenicity studies in animal models by measuring serum antibodies (IgG1, IgG2a, and IgA) and cytokines (IFN-γ and IL5) revealed that the rFlaA induces a proper immune response in animal models. CONCLUSION:The recombinant FlaA protein is antigenic and immunogenic. Therefore, it might be used in order to design of specific diagnostic kits and recombinant vaccines against H. pylori.
| S-EPMC5651478 | biostudies-literature
Project description:The human gastric pathogen Helicobacter pylori is usually acquired during childhood and, in the absence of treatment, chronic infection persists through most of the host's life. However, the frequency and importance of H. pylori transmission between adults is underestimated. Here we sequenced the complete genomes of H. pylori strains that were transmitted between spouses and analysed the genomic changes. Similar to H. pylori from chronic infection, a significantly high proportion of the determined 31 SNPs and 10 recombinant DNA fragments affected genes of the hop family of outer membrane proteins, some of which are known to be adhesins. In addition, changes in a fucosyltransferase gene modified the LPS component of the bacterial cell surface, suggesting strong diversifying selection. In contrast, virulence factor genes were not affected by the genomic changes. We propose a model of the genomic changes that are associated with the transmission and adaptation of H. pylori to a new human host.
| S-EPMC3858298 | biostudies-literature
Project description:This manuscript is an up-to-date review of experimentally validated linear and continuous epitopes identified from arbovirus members of the Flavivirus genus. We summarized 153 immunoreactive peptides from the Dengue virus, Zika virus, Japanese encephalitis virus, West Nile virus, and tick-borne encephalitis virus described in studies published from 1989 to 2020. We included peptides from structural (envelope, capsid, and pre-membrane) and nonstructural (Ns1-5) viral proteins that demonstrated relevant immunoreactivity with antibodies from naturally infected or vaccinated humans. We included peptides that demonstrated relevant reactivity features, such as indicators of disease severity related to immunological or immunopathological outcomes, differential or group diagnostic markers, immunotherapy candidates, and potential for vaccine formulation. The majority of immunoreactive peptides were described for DENV probably due to its long-lasting impact on human health and the lack of efficient vaccines and therapeutic methods. Immune landscape data regarding linear immunoreactive and continuous flavivirus peptides are still scarce, and a complete and more detailed map remains to be elucidated. Therefore, this review provides valuable data for those investigating the antibody response against flavivirus infection.
| S-EPMC8387565 | biostudies-literature
Project description:Helicobacter pylori is the leading cause of gastritis, peptic ulcer disease and gastric adenocarcinoma and lymphoma in humans. Due to the decreasing efficacy of anti-H. pylori antibiotic therapy in clinical practice, there is renewed interest in the development of anti-H. pylori vaccines. In this study an in silico-based approach was utilized to develop a multi-epitope DNA-prime/peptide-boost immunization strategy using informatics tools. The efficacy of this construct was then assessed as a therapeutic vaccine in a mouse model of gastric cancer induced by chronic H. pylori infection. The multi-epitope vaccine administered intranasally induced a broad immune response as determined by interferon-gamma production in ELISpot assays. This was associated with a significant reduction in H. pylori colonization compared with mice immunized with the same vaccine intramuscularly, given an empty plasmid, or given a whole H. pylori lysate intranasally as the immunogen. Total scores of gastric histological changes were not significantly different among the 4 experimental groups. These results suggest that further development of an epitope-based mucosal vaccine may be beneficial in eradicating H. pylori and reducing the burden of the associated gastric diseases in humans.
| S-EPMC3046230 | biostudies-literature
Project description:BackgroundComprehensive characterization of exposures and immune responses to viral infections is critical to a basic understanding of human health and disease. We previously developed the VirScan system, a programmable phage-display technology for profiling antibody binding to a library of peptides designed to span the human virome. Previous VirScan analytical approaches did not carefully account for antibody cross-reactivity among sequences shared by related viruses or for the disproportionate representation of individual viruses in the library.MethodsHere we present the AntiViral Antibody Response Deconvolution Algorithm (AVARDA), a multi-module software package for analyzing VirScan datasets. AVARDA provides a probabilistic assessment of infection with species-level resolution by considering sequence alignment of all library peptides to each other and to all human viruses. We employed AVARDA to analyze VirScan data from a cohort of encephalitis patients with either known viral infections or undiagnosed etiologies. We further assessed AVARDA's utility in associating viral infection with type 1 diabetes and lupus.FindingsBy comparing acute and convalescent sera, AVARDA successfully confirmed or detected encephalitis-associated responses to human herpesviruses 1, 3, 4, 5, and 6, improving the rate of diagnosing viral encephalitis in this cohort by 44%. AVARDA analyses of VirScan data from the type 1 diabetes and lupus cohorts implicated enterovirus and herpesvirus infections, respectively.InterpretationAVARDA, in combination with VirScan and other pan-pathogen serological techniques, is likely to find broad utility in the epidemiology and diagnosis of infectious diseases.FundingThis work was made possible by support from the National Institutes of Health (NIH), the US Army Research Office, the Singapore Infectious Diseases Initiative (SIDI), the Singapore Ministry of Health's National Medical Research Council (NMRC) and the Singapore National Research Foundation (NRF).
| S-EPMC8688874 | biostudies-literature