scholarly journals Contribution of Secretory Antibodies to Intestinal Mucosal Immunity against Helicobacter pylori

2013 ◽  
Vol 81 (10) ◽  
pp. 3880-3893 ◽  
Author(s):  
Rebecca J. Gorrell ◽  
Odilia L. C. Wijburg ◽  
John S. Pedersen ◽  
Anna K. Walduck ◽  
Terry Kwok ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antibody Response ◽  
Bacterial Load ◽  
Secretory Iga ◽  
Mouse Strains ◽  
Wild Type ◽  
Content Type ◽  
Immunoglobulin Receptor ◽  
H Pylori ◽  
Secretory Antibodies

ABSTRACTThe natural immune response toHelicobacter pylorineither clears infection nor prevents reinfection. However, the ability of secretory antibodies to influence the course ofH. pyloriinfection has not been determined. We compared the natural progression ofH. pyloriinfection in wild-type C57BL/6 mice with that in mice lacking the polymeric immunoglobulin receptor (pIgR) that is essential for the secretion of polymeric antibody across mucosal surfaces.H. pyloriSS1-infected wild-type and pIgR knockout (KO) mice were sampled longitudinally for gastrointestinal bacterial load, antibody response, and histological changes. The gastric bacterial loads of wild-type and pIgR KO mice remained constant and comparable at up to 3 months postinfection (mpi) despite SS1-reactive secretory IgA in the intestinal contents of wild-type mice at that time. Conversely, abundant duodenal colonization of pIgR KO animals contrasted with the near-total eradication ofH. pylorifrom the intestine of wild-type animals by 3 mpi.H. pyloriwas cultured only from the duodenum of those animals in which colonization in the distal gastric antrum was of sufficient density for immunohistological detection. By 6 mpi, the gastric load ofH. pyloriin wild-type mice was significantly lower than in pIgR KO animals. While there was no corresponding difference between the two mouse strains in gastric pathology results at 6 mpi, reductions in gastric bacterial load correlated with increased gastric inflammation together with an intestinal secretory antibody response in wild-type mice. Together, these results suggest that naturally produced secretory antibodies can modulate the progress ofH. pyloriinfection, particularly in the duodenum.

scholarly journals The Helicobacter pylori Autotransporter ImaA (HP0289) Modulates the Immune Response and Contributes to Host Colonization

2012 ◽  
Vol 80 (7) ◽  
pp. 2286-2296 ◽  
Author(s):  
William E. Sause ◽  
Andrea R. Castillo ◽  
Karen M. Ottemann
Keyword(s):  
Immune Response ◽  
Helicobacter Pylori ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Dependent Manner ◽  
Wild Type ◽  
Content Type ◽  
H Pylori ◽  
Murine Infections

ABSTRACTThe human pathogenHelicobacter pyloriemploys a diverse collection of outer membrane proteins to colonize, persist, and drive disease within the acidic gastric environment. In this study, we sought to elucidate the function of the host-induced geneHP0289, which encodes an uncharacterized outer membrane protein. We first generated an isogenicH. pylorimutant that lacksHP0289and found that the mutant has a colonization defect in single-strain infections and is greatly outcompeted in mouse coinfection experiments with wild-typeH. pylori. Furthermore, we used protease assays and biochemical fractionation coupled with an HP0289-targeted peptide antibody to verify that the HP0289 protein resides in the outer membrane. Our previous findings showed that theHP0289promoter is upregulated in the mouse stomach, and here we demonstrate thatHP0289expression is induced under acidic conditions in an ArsRS-dependent manner. Finally, we have shown that theHP0289mutant induces greater expression of the chemokine interleukin-8 (IL-8) and the cytokine tumor necrosis factor alpha (TNF-α) in gastric carcinoma cells (AGS). Similarly, transcription of the IL-8 homolog keratinocyte-derived chemokine (KC) is elevated in murine infections with the HP0289 mutant than in murine infections with wild-typeH. pylori. On the basis of this phenotype, we renamed HP0289 ImaA forimmunomodulatoryautotransporter protein. Our work has revealed that genes inducedin vivoplay an important role inH. pyloripathogenesis. Specifically, the outer membrane protein ImaA modulates a component of the host inflammatory response, and thus may allowH. pylorito fine tune the host immune response based on ImaA expression.

scholarly journals Systems Modeling of the Role of Interleukin-21 in the Maintenance of Effector CD4+ T Cell Responses during Chronic Helicobacter pylori Infection

mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Adria Carbo ◽  
Danyvid Olivares-Villagómez ◽  
Raquel Hontecillas ◽  
Josep Bassaganya-Riera ◽  
Rupesh Chaturvedi ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
T Cell ◽  
Wild Type ◽  
Content Type ◽  
Interleukin 21 ◽  
H Pylori ◽  
Deficient Mice

ABSTRACTThe development of gastritis duringHelicobacter pyloriinfection is dependent on an activated adaptive immune response orchestrated by T helper (Th) cells. However, the relative contributions of the Th1 and Th17 subsets to gastritis and control of infection are still under investigation. To investigate the role of interleukin-21 (IL-21) in the gastric mucosa duringH. pyloriinfection, we combined mathematical modeling of CD4+T cell differentiation within vivomechanistic studies. We infected IL-21-deficient and wild-type mice withH. pyloristrain SS1 and assessed colonization, gastric inflammation, cellular infiltration, and cytokine profiles. ChronicallyH. pylori-infected IL-21-deficient mice had higherH. pyloricolonization, significantly less gastritis, and reduced expression of proinflammatory cytokines and chemokines compared to these parameters in infected wild-type littermates. Thesein vivodata were used to calibrate anH. pyloriinfection-dependent, CD4+T cell-specific computational model, which then described the mechanism by which IL-21 activates the production of interferon gamma (IFN-γ) and IL-17 during chronicH. pyloriinfection. The model predicted activated expression of T-bet and RORγt and the phosphorylation of STAT3 and STAT1 and suggested a potential role of IL-21 in the modulation of IL-10. Driven by our modeling-derived predictions, we found reduced levels of CD4+splenocyte-specifictbx21androrcexpression, reduced phosphorylation of STAT1 and STAT3, and an increase in CD4+T cell-specific IL-10 expression inH. pylori-infected IL-21-deficient mice. Our results indicate that IL-21 regulates Th1 and Th17 effector responses during chronicH. pyloriinfection in a STAT1- and STAT3-dependent manner, therefore playing a major role controllingH. pyloriinfection and gastritis.IMPORTANCEHelicobacter pyloriis the dominant member of the gastric microbiota in more than 50% of the world’s population.H. pyloricolonization has been implicated in gastritis and gastric cancer, as infection withH. pyloriis the single most common risk factor for gastric cancer. Current data suggest that, in addition to bacterial virulence factors, the magnitude and types of immune responses influence the outcome of colonization and chronic infection. This study uses a combined computational and experimental approach to investigate how IL-21, a proinflammatory T cell-derived cytokine, maintains the chronic proinflammatory T cell immune response driving chronic gastritis duringH. pyloriinfection. This research will also provide insight into a myriad of other infectious and immune disorders in which IL-21 is increasingly recognized to play a central role. The use of IL-21-related therapies may provide treatment options for individuals chronically colonized withH. pylorias an alternative to aggressive antibiotics.

scholarly journals The Helicobacter pylori Autotransporter ImaA Tempers the Bacterium's Interaction with α5β1 Integrin

2016 ◽  
Vol 85 (1) ◽  
Author(s):  
William E. Sause ◽  
Daniela Keilberg ◽  
Soufiane Aboulhouda ◽  
Karen M. Ottemann
Keyword(s):  
Helicobacter Pylori ◽  
Host Cell ◽  
Type Iv Secretion ◽  
Host Cells ◽  
Wild Type ◽  
Content Type ◽  
Type Iv ◽  
H Pylori ◽  
Α5β1 Integrin ◽  
Cell Interface

ABSTRACT The human pathogen Helicobacter pylori uses the host receptor α5β1 integrin to trigger inflammation in host cells via its cag pathogenicity island (cag PAI) type IV secretion system (T4SS). Here, we report that the H. pylori ImaA protein (HP0289) decreases the action of the cag PAI T4SS via tempering the bacterium's interaction with α5β1 integrin. Previously, imaA-null mutants were found to induce an elevated inflammatory response that was dependent on the cag PAI T4SS; here we extend those findings to show that the elevated response is independent of the CagA effector protein. To understand how ImaA could be affecting cag PAI T4SS activity at the host cell interface, we utilized the Phyre structural threading program and found that ImaA has a region with remote homology to bacterial integrin-binding proteins. This region was required for ImaA function. Unexpectedly, we observed that imaA mutants bound higher levels of α5β1 integrin than wild-type H. pylori, an outcome that required the predicted integrin-binding homology region of ImaA. Lastly, we report that ImaA directly affected the amount of host cell β1 integrin but not other cellular integrins. Our results thus suggest a model in which H. pylori employs ImaA to regulate interactions between integrin and the T4SS and thus alter the host inflammatory strength.

scholarly journals Novel Functions for Glycosyltransferases Jhp0562 and GalT in Lewis Antigen Synthesis and Variation in Helicobacter pylori

2012 ◽  
Vol 80 (4) ◽  
pp. 1593-1605 ◽  
Author(s):  
Mary Ann Pohl ◽  
Sabine Kienesberger ◽  
Martin J. Blaser
Keyword(s):  
Helicobacter Pylori ◽  
Wild Type ◽  
Sequence Analyses ◽  
Upstream Gene ◽  
Content Type ◽  
Lewis Antigen ◽  
Mutant Strains ◽  
H Pylori

ABSTRACTLewis (Le) antigens are fucosylated oligosaccharides present in theHelicobacter pylorilipopolysaccharide. Expression of these antigens is believed to be important forH. pyloricolonization, since Le antigens also are expressed on the gastric epithelia in humans. A galactosyltransferase encoded by β-(1,3)galTis essential for production of type 1 (Leaand Leb) antigens. The upstream genejhp0562, which is present in many but not allH. pyloristrains, is homologous to β-(1,3)galTbut is of unknown function. BecauseH. pyloridemonstrates extensive intragenomic recombination, we hypothesized that these two genes could undergo DNA rearrangement. A PCR screen and subsequent sequence analyses revealed that the two genes can recombine at both the 5′ and 3′ ends. Chimeric β-(1,3)galT-like alleles can restore function in a β-(1,3)galTnull mutant, but neither native nor recombinantjhp0562can. Mutagenesis ofjhp0562revealed that it is essential for synthesis of both type 1 and type 2 Le antigens. Transcriptional analyses of both loci showed β-(1,3)galTexpression in all wild-type (WT) and mutant strains tested, whereasjhp0562was not expressed injhp0562null mutants, as expected. Sincejhp0562unexpectedly displayed functions in both type 1 and type 2 Le synthesis, we asked whethergalT, part of the type 2 synthesis pathway, had analogous functions in type 1 synthesis. Mutagenesis and complementation analysis confirmed thatgalTis essential for Lebproduction. In total, these results demonstrate thatgalTandjhp0562have functions that cross the expected Le synthesis pathways and thatjhp0562provides a substrate for intragenomic recombination to generate diverse Le synthesis enzymes.

scholarly journals Localized Suppression of Inflammation at Sites of Helicobacter pylori Colonization

2011 ◽  
Vol 79 (10) ◽  
pp. 4186-4192 ◽  
Author(s):  
Alison L. Every ◽  
Garrett Z. Ng ◽  
Caroline D. Skene ◽  
Stacey N. Harbour ◽  
Anna K. Walduck ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Potential Model ◽  
Gastric Ph ◽  
Male Mice ◽  
Wild Type ◽  
Content Type ◽  
Female Mice ◽  
Gastric Corpus ◽  
Acid Secreting ◽  
H Pylori

ABSTRACTWhile gastric adenocarcinoma is the most serious consequence ofHelicobacter pyloriinfection, not all infected persons develop this pathology. Individuals most at risk of this cancer are those in whom the bacteria colonize the acid-secreting region of the stomach and subsequently develop severe inflammation in the gastric corpus. It has been reported anecdotally that male mice become infected with greater numbers ofH. pyloribacteria than female mice. While investigating this phenomenon, we found that increasedH. pyloriinfection densities in male mice were not related to antibody production, and this phenomenon was not normalized by gonadectomy. However, the gastric pH in male 129/Sv mice was significantly elevated compared with that in female mice. Differences in colonization were evident within 1 day postinfection and significantly arose due to colonization of the gastric corpus region in male mice. This provided a potential model for comparing the effect of corpus colonization on the development of gastritis. This was explored using two models ofH. pylori-induced inflammation, namely, 2-month infections ofMuc1−/−mice and 6-month infections of wild-type 129/Sv mice. WhileH. pyloriinfection of female mice induced a severe, corpus-predominant atrophic gastritis, to our surprise, male mice developed minimal inflammation despite being colonized with significantly moreH. pyloribacteria than female controls. Thus, colonization of the gastric corpus in male mice was associated with a loss of inflammation in that region. The suppression of inflammation concomitant with infection of the gastric corpus in male mice demonstrates a powerful localized suppression of inflammation induced at sites ofH. pyloricolonization.

scholarly journals Helicobacter pylori Stores Nickel To Aid Its Host Colonization

2012 ◽  
Vol 81 (2) ◽  
pp. 580-584 ◽  
Author(s):  
Stéphane L. Benoit ◽  
Erica F. Miller ◽  
Robert J. Maier
Keyword(s):  
Helicobacter Pylori ◽  
Gastric Mucosa ◽  
Physiological Role ◽  
Wild Type ◽  
Rank Tests ◽  
Content Type ◽  
Host Mouse ◽  
H Pylori ◽  
Very High

ABSTRACTThe transition metal nickel (Ni) is critical for the pathogenicity ofHelicobacter pylori. Indeed the element is a required component of two enzymes, hydrogenase and urease, that have been shown to be important forin vivocolonization of the host gastric mucosa. Urease accounts for up to 10% of the total cellularH. pyloriprotein content, and therefore the bacterial Ni demand is very high.H. pyloripossess two small and abundant histidine-rich, Ni-binding proteins, Hpn and Hpn-like, whose physiological role in the host have not been investigated. In this study, special husbandry conditions were used to control Ni levels in the host (mouse), including the use of Ni-free versus Ni-supplemented food. The efficacy of each diet was confirmed by measuring the Ni concentrations in sera of mice fed with either diet. Colonization levels (based on rank tests) of theΔhpn Δhpn-like double mutants isolated from the mice provided Ni-deficient chow were statistically lower than those for mice given Ni in their diet. In contrast,H. pyloriwild-type colonization levels were similar in both host groups (e.g., regardless of Ni levels). Our results indicate that the gastric pathogenH. pylorican utilize stored Ni via defined histidine-rich proteins to aid colonization of the host.

scholarly journals A Double Mutant Heat-Labile Toxin from Escherichia coli, LT(R192G/L211A), Is an Effective Mucosal Adjuvant for Vaccination against Helicobacter pylori Infection

2013 ◽  
Vol 81 (5) ◽  
pp. 1532-1540 ◽  
Author(s):  
Louise Sjökvist Ottsjö ◽  
Carl-Fredrik Flach ◽  
John Clements ◽  
Jan Holmgren ◽  
Sukanya Raghavan
Keyword(s):  
Escherichia Coli ◽  
Helicobacter Pylori ◽  
Immune Responses ◽  
Double Mutant ◽  
Bacterial Load ◽  
Mucosal Vaccine ◽  
Mucosal Adjuvant ◽  
Content Type ◽  
Heat Labile ◽  
H Pylori

ABSTRACTHelicobacter pyloriinfection in the stomach is a common cause of peptic ulcer disease and is a strong risk factor for the development of gastric adenocarcinoma, yet no effective vaccine againstH. pyloriinfection is available to date. In mice, mucosal vaccination withH. pyloriantigens when given together with cholera toxin (CT) adjuvant, but not without adjuvant, can induce protective immune responses againstH. pyloriinfection. However, the toxicity of CT precludes its use as a mucosal adjuvant in humans. We evaluated a recently developed, essentially nontoxic double mutantEscherichia coliheat-labile toxin, LT(R192G/L211A) (dmLT), as a mucosal adjuvant in an experimentalH. pylorivaccine and compared it to CT in promoting immune responses and protection againstH. pyloriinfection in mice. Immunization via the sublingual or intragastric route withH. pylorilysate antigens and dmLT resulted in a significant decrease in bacterial load after challenge compared to that in unimmunized infection controls and to the same extent as when using CT as an adjuvant. Cellular immune responses in the sublingually immunized mice known to correlate with protection were also fully comparable when using dmLT and CT as adjuvants, resulting in enhancedin vitroproliferative and cytokine responses from spleen and mesenteric lymph node cells toH. pyloriantigens. Our results suggest that dmLT is an attractive adjuvant for inclusion in a mucosal vaccine againstH. pyloriinfection.

scholarly journals Immunological Response to Parenteral Vaccination with Recombinant Hepatitis B Virus Surface Antigen Virus-Like Particles Expressing Helicobacter pylori KatA Epitopes in a Murine H. pylori Challenge Model

2011 ◽  
Vol 19 (2) ◽  
pp. 268-276 ◽  
Author(s):  
Michael Kotiw ◽  
Megan Johnson ◽  
Manisha Pandey ◽  
Scott Fry ◽  
Stuart L. Hazell ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Bacterial Load ◽  
Igg Antibody ◽  
Virus Surface ◽  
Content Type ◽  
Virus Like Particles ◽  
B Virus ◽  
H Pylori

ABSTRACTVirus-like particles (VLPs) based on the small envelope protein of hepatitis B virus (HBsAg-S) are immunogenic at the B- and T-cell level. In this study, we inserted overlapping sequences encoding the carboxy terminus of theHelicobacter pylori katAgene product into HBsAg-S. The HBsAg-S–KatA fusion proteins were able to assemble into secretion-competent VLPs (VLP-KatA). The VLP-KatA proteins were able to induce KatA-specific antibodies in immunized mice. The mean total IgG antibody titers 41 days post-primary immunization with VLP-KatA (2.3 × 103) were significantly greater (P< 0.05) than those observed for vaccination with VLP alone (5.2 × 102). Measurement of IgG isotypes revealed responses to both IgG1 and IgG2a (mean titers, 9.0 × 104and 2.6 × 104, respectively), with the IgG2a response to vaccination with VLP-KatA being significantly higher than that for mice immunized with KatA alone (P< 0.05). Following challenge of mice withH. pylori, a significantly reduced bacterial load in the gastric mucosa was observed (P< 0.05). This is the first report describing the use of VLPs as a delivery vehicle forH. pyloriantigens.

scholarly journals Peptidoglycan Deacetylation in Helicobacter pylori Contributes to Bacterial Survival by Mitigating Host Immune Responses

2010 ◽  
Vol 78 (11) ◽  
pp. 4660-4666 ◽  
Author(s):  
Ge Wang ◽  
Susan E. Maier ◽  
Leja F. Lo ◽  
George Maier ◽  
Shruti Dosi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Helicobacter Pylori ◽  
Immune Responses ◽  
Bacterial Load ◽  
Host Cells ◽  
Infection Model ◽  
Wild Type ◽  
Mouse Infection Model ◽  
Mouse Infection ◽  
H Pylori

ABSTRACT An oxidative stress-induced enzyme, peptidoglycan deacetylase (PgdA), in the human gastric pathogen Helicobacter pylori was previously identified and characterized. In this study, we constructed H. pylori pgdA mutants in two mouse-adapted strains, X47 and B128, to investigate the role of PgdA in vivo (to determine the mutants’ abilities to colonize mice and to induce an immune response). H. pylori pgdA mutant cells showed increased sensitivity to lysozyme compared to the sensitivities of the parent strains. We demonstrated that the expression of PgdA was significantly induced (3.5-fold) when H. pylori cells were in contact with macrophages, similar to the effect observed with oxidative stress as the environmental inducer. Using a mouse infection model, we first examined the mouse colonization ability of an H. pylori pgdA mutant in X47, a strain deficient in the major pathway (cag pathogenicity island [PAI] encoded) for delivery of peptidoglycan into host cells. No animal colonization difference between the wild type and the mutant was observed 3 weeks after inoculation. However, the pgdA mutant showed a significantly attenuated ability to colonize mouse stomachs (9-fold-lower bacterial load) at 9 weeks postinoculation. With the cag PAI-positive strain B128, a significant colonization difference between the wild type and the pgdA mutant was observed at 3 weeks postinoculation (1.32 × 104 versus 1.85 × 103 CFU/gram of stomach). To monitor the immune responses elicited by H. pylori in the mouse infection model, we determined the concentrations of cytokines present in mouse sera. In the mice infected with the pgdA mutant strain, we observed a highly significant increase in the level of MIP-2. In addition, significant increases in interleukin-10 and tumor necrosis factor alpha in the pgdA mutant-infected mice compared to the levels in the wild-type H. pylori-infected mice were also observed. These results indicated that H. pylori peptidoglycan deacetylation is an important mechanism for mitigating host immune detection; this likely contributes to pathogen persistence.

scholarly journals A Novel DNA-Binding Protein Plays an Important Role in Helicobacter pylori Stress Tolerance and Survival in the Host

2014 ◽  
Vol 197 (5) ◽  
pp. 973-982 ◽  
Author(s):  
Ge Wang ◽  
Robert J. Maier
Keyword(s):  
Oxidative Stress ◽  
Helicobacter Pylori ◽  
Dna Binding ◽  
Stress Tolerance ◽  
Mutant Strain ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Wild Type ◽  
Content Type ◽  
H Pylori

The gastric pathogenHelicobacter pylorimust combat chronic acid and oxidative stress. It does so via many mechanisms, including macromolecule repair and gene regulation. Mitomycin C-sensitive clones from a transposon mutagenesis library were screened. One sensitive strain contained the insertion element at the locus ofhp119, a hypothetical gene. No homologous gene exists in any (non-H. pylori) organism. Nevertheless, the predicted protein has some features characteristic of histone-like proteins, and we showed that purified HP119 protein is a DNA-binding protein. A Δhp119strain was markedly more sensitive (viability loss) to acid or to air exposure, and these phenotypes were restored to wild-type (WT) attributes upon complementation of the mutant with the wild-type version ofhp119at a separate chromosomal locus. The mutant strain was approximately10-fold more sensitive to macrophage-mediated killing than the parent or the complemented strain. Of 12 mice inoculated with the wild type, all containedH. pylori, whereas 5 of 12 mice contained the mutant strain; the mean colonization numbers were 158-fold less for the mutant strain. A proteomic (two-dimensional PAGE with mass spectrometric analysis) comparison between the Δhp119mutant and the WT strain under oxidative stress conditions revealed a number of important antioxidant protein differences; SodB, Tpx, TrxR, and NapA, as well as the peptidoglycan deacetylase PgdA, were significantly less expressed in the Δhp119mutant than in the WT strain. This study identified HP119 as a putative histone-like DNA-binding protein and showed that it plays an important role inHelicobacter pyloristress tolerance and survival in the host.

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