scholarly journals Role of Gamma Interferon in Helicobacter pylori-Induced Gastric Inflammatory Responses in a Mouse Model

1999 ◽  
Vol 67 (1) ◽  
pp. 279-285 ◽  
Author(s):  
Naoki Sawai ◽  
Masakazu Kita ◽  
Tadashi Kodama ◽  
Toshihito Tanahashi ◽  
Yoshio Yamaoka ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Immune Responses ◽  
Mononuclear Cells ◽  
Inflammatory Responses ◽  
Gene Knockout ◽  
Gamma Interferon ◽  
Gastric Epithelium ◽  
Wild Type ◽  
Ifn Γ ◽  
H Pylori

ABSTRACT The immune responses to Helicobacter pylori infection play important roles in gastroduodenal diseases. The contribution of gamma interferon (IFN-γ) to the immune responses, especially to the induction of gastric inflammation and to protection from H. pylori infection, was investigated with IFN-γ gene knockout (IFN-γ−/−) mice. We first examined the colonizing abilities of eight H. pylori strains with a short-term infection test in order to select H. pylori strains which could colonize the mouse stomach. Only three strains (ATCC 43504, CPY2052, and HPK127) colonized C57BL/6 wild-type mice, although all of the strains except for ATCC 51110 could colonize IFN-γ−/− mice. The number of H. pyloriorganisms colonizing the stomach in wild-type mice was lower than that in IFN-γ−/− mice. Oral immunization with the CPY2052 sonicate and cholera toxin protected against infection with strain CPY2052 in both types of mouse. These findings suggested that IFN-γ may play a protective role in H. pylori infection, although the degree of its protective ability was estimated to be low. In contrast, in a long-term infection test done to examine the contribution of IFN-γ to gastric inflammation, CPY2052-infected wild-type mice developed a severe infiltration of mononuclear cells in the lamina propria and erosions in the gastric epithelium 15 months after infection, whereas CPY2052-infected IFN-γ−/− mice showed no inflammatory symptoms. This result clearly demonstrated that IFN-γ plays an important role in the induction of gastric inflammation caused by H. pylori infection.

scholarly journals Role of Gamma Interferon in Helicobacter pylori Induction of Inflammatory Mediators during Murine Infection

2002 ◽  
Vol 70 (6) ◽  
pp. 3295-3299 ◽  
Author(s):  
Marygorret Obonyo ◽  
Donald G. Guiney ◽  
Julia Harwood ◽  
Joshua Fierer ◽  
Sheri P. Cole
Keyword(s):  
Helicobacter Pylori ◽  
Gene Knockout ◽  
Gamma Interferon ◽  
Epithelial Cell Line ◽  
Inos Mrna ◽  
Inflammatory Protein ◽  
Ifn Γ ◽  
H Pylori ◽  
Oxide Synthase

ABSTRACT Gamma interferon (IFN-γ) has been proposed to play an important role in Helicobacter-related gastritis. Using the IFN-γ gene knockout (IFN-γ−/−) mouse model and a murine gastric epithelial cell line, GSM06, we demonstrated that Helicobacter pylori maximally induced macrophage inflammatory protein-2 (MIP-2) and inducible nitric oxide synthase (iNOS) mRNA only in wild-type mice. MIP-2 and iNOS mRNA were also induced by H. pylori in GSM06 cells. Induction of cyclooxygenase 2 mRNA through IFN-γ was demonstrated in GSM06 cells. These data indicate that IFN-γ mediates the induction of MIP-2 and iNOS mRNA expression by H. pylori in mice.

scholarly journals Helicobacter pylori with a Truncated Lipopolysaccharide O Chain Fails To Induce Gastritis in SCID Mice Injected with Splenocytes from Wild-Type C57BL/6J Mice

2004 ◽  
Vol 72 (7) ◽  
pp. 3925-3931 ◽  
Author(s):  
K. A. Eaton ◽  
S. M. Logan ◽  
P. E. Baker ◽  
R. A. Peterson ◽  
M. A. Monteiro ◽  
...  
Keyword(s):  
Immune Response ◽  
Helicobacter Pylori ◽  
Immune Responses ◽  
Scid Mice ◽  
Delayed Type Hypersensitivity ◽  
Wild Type ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Ifn Γ ◽  
H Pylori

ABSTRACT The goal of this study was to determine whether Helicobacter pylori lipopolysaccharide (LPS) O-chain polysaccharide contributes to gastritis in a mouse model. C57BL/6J or C57BL/6-Prkdcscid (severe combined immunodeficient [SCID]) mice were inoculated with H. pylori strain SS1 or SS1::0826kan, in which a β-1,4-galactosyltransferase (HP0826), an LPS biosynthetic enzyme, had been disrupted. H. pylori strain SS1::0826kan expresses truncated LPS lacking O chain. Recipient SCID mice were given C57BL/6J splenocytes by intraperitoneal injection. Bacterial colonization, gastric lesions (gastritis, neutrophilic infiltration, and gastric epithelial metaplasia), cellular (delayed-type hypersensitivity) and humoral immune responses to H. pylori sonicate, and gastric gamma interferon (IFN-γ) mRNA expression were quantified. Recipient SCID mice colonized by H. pylori strain SS1 developed extensive gastritis with loss of normal fundic gland morphology. In contrast, gastric mucosa of recipient SCID mice colonized by H. pylori strain SS1::0826kan was not statistically distinguishable from that of uninfected recipient mice. Delayed-type hypersensitivity and humoral immune responses were detected in infected mice inoculated with wild-type SS1, but not with SS1::0826kan. IFN-γ transcription was lower in mice infected with SS1::0826kan than in mice infected with SS1. In this model of rapidly progressive gastritis due to H. pylori, the O chain contributed to the extent of gastritis and to the host immune response. These data support a role for H. pylori LPS O chain in direct induction of the host immune response leading to gastritis and gastric damage and are in contrast to protein antigens, such as urease and cag products which do not contribute to gastritis in mice.

scholarly journals Helicobacter pylori Disrupts STAT1-Mediated Gamma Interferon-Induced Signal Transduction in Epithelial Cells

2004 ◽  
Vol 72 (1) ◽  
pp. 537-545 ◽  
Author(s):  
David J. Mitchell ◽  
Hien Q. Huynh ◽  
Peter J. M. Ceponis ◽  
Nicola L. Jones ◽  
Philip M. Sherman
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Tyrosine Phosphorylation ◽  
Nuclear Translocation ◽  
Gamma Interferon ◽  
Cell Protein ◽  
Stat1 Signaling ◽  
Ifn Γ ◽  
H Pylori

ABSTRACT Infection with Helicobacter pylori is chronic despite a vigorous mucosal immune response characterized by gastric T-helper type 1 cell expansion and gamma interferon (IFN-γ) production. IFN-γ signals by activation and nuclear translocation of signal transducer and activator of transcription 1 (STAT1); however, the effect of H. pylori infection on IFN-γ-STAT1 signaling is unknown. We infected human gastric (MKN45 and AGS) and laryngeal (HEp-2) epithelial cell lines with type 1 and type 2 H. pylori strains and then stimulated them with IFN-γ. Western blotting of whole-cell protein extracts revealed that infection with live, but not heat-killed, H. pylori time-dependently decreased IFN-γ-induced STAT1 tyrosine phosphorylation. Electrophoretic mobility shift assay of nuclear protein extracts demonstrated that H. pylori infection reduced IFN-γ-induced STAT1 DNA binding. STAT1 was unable to translocate from the cytoplasm to the nucleus in H. pylori-infected HEp-2 cells examined by immunofluorescence, and reverse transcription-PCR showed that IFN-γ-induced interferon regulatory factor 1 expression was inhibited. These effects were independent of the cagA, cagE, and VacA status of the infecting H. pylori strain. Furthermore, neither H. pylori culture supernatants nor conditioned medium from H. pylori-infected MKN45 cells inhibited IFN-γ-induced STAT1 tyrosine phosphorylation, suggesting that inhibition is independent of a soluble epithelial or bacterial factor but is dependent on bacterial contact with epithelial cells. H. pylori disruption of IFN-γ-STAT1 signaling in epithelial cells may represent a mechanism by which the bacterium modifies mucosal immune responses to promote its survival in the human host.

scholarly journals Vaccine-Induced Reduction of Helicobacter pylori Colonization in Mice Is Interleukin-12 Dependent but Gamma Interferon and Inducible Nitric Oxide Synthase Independent

2003 ◽  
Vol 71 (2) ◽  
pp. 910-921 ◽  
Author(s):  
Christine A. Garhart ◽  
Frederick P. Heinzel ◽  
Steven J. Czinn ◽  
John G. Nedrud
Keyword(s):  
Nitric Oxide ◽  
Helicobacter Pylori ◽  
Nitric Oxide Synthase ◽  
Inducible Nitric Oxide Synthase ◽  
Bacterial Load ◽  
Gamma Interferon ◽  
Ifn Γ ◽  
H Pylori ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

ABSTRACT Previous studies with mice have shown that major histocompatibility complex class II (MHC-II) is required for protection from Helicobacter pylori, while MHC-I and antibodies are not. Thus, CD4+ T cells are presumed to play an essential role in protective immunity via secretion of cytokines. To determine which cytokines are associated with a reduction of bacterial load in immunized mice, gastric cytokine expression was examined by semiquantitative reverse transcription-PCR in protected (defined as ≥2-log-unit decrease in bacterial load) and unprotected mice 4 weeks after challenge. Elevated levels of mRNA for interleukin-12p40 (IL-12p40), gamma interferon (IFN-γ), tumor necrosis factor alpha, and inducible nitric oxide synthase (iNOS) were associated with protection in immunized-challenged (I/C) mice, but Th2 cytokine (IL-4, IL-5, IL-10, and IL-13) and chemokine (KC, MIP-2, and MCP-1) expression was not associated with protection. Despite the association of IFN-γ and iNOS message with protection, I/C mice genetically lacking either of these products were able to reduce the bacterial load as well as the wild-type I/C controls. The I/C mice lacking IL-12p40 were not protected compared to unimmunized-challenged mice. All I/C groups developed gastritis. We conclude that neither IFN-γ nor iNOS is essential for vaccine-induced protection from H. pylori infection. The p40 subunit of IL-12, which is a component of both IL-12 and IL-23, is necessary for protection in immunized mice. These findings suggest a novel IFN-γ-independent function of IL-12p40 in effective mucosal immunization against H. pylori.

scholarly journals Modulation of Innate Cytokine Responses by Products of Helicobacter pylori

2000 ◽  
Vol 68 (11) ◽  
pp. 6265-6272 ◽  
Author(s):  
Frank Meyer ◽  
Keith T. Wilson ◽  
Stephen P. James
Keyword(s):  
Immune Response ◽  
Helicobacter Pylori ◽  
Lymphocyte Proliferation ◽  
Mononuclear Cells ◽  
Cytokine Production ◽  
Peripheral Blood Mononuclear ◽  
Cytokine Responses ◽  
Ifn Γ ◽  
H Pylori ◽  
Th1 Polarization

ABSTRACT The gastric inflammatory and immune response in Helicobacter pylori infection may be due to the effect of different H. pylori products on innate immune mechanisms. The aim of this study was to determine whether bacterial components could modulate cytokine production in vitro and thus contribute to Th1 polarization of the gastric immune response observed in vivo. The effect of H. pylori recombinant urease, bacterial lysate, intact bacteria, and bacterial DNA on proliferation and cytokine production by peripheral blood mononuclear cells (PBMCs) from H. pylori-negative donors was examined as a model for innate cytokine responses. Each of the different H. pylori preparations induced gamma interferon (IFN-γ) and interleukin-12p40 (IL-12p40), but not IL-2 or IL-5, production, and all but H. pylori DNA stimulated release of IL-10. Addition of anti-IL-12 antibody to cultures partially inhibited IFN-γ production. In addition, each bacterial product inhibited mitogen-stimulated IL-2 production by PBMCs and Jurkat T cells. The inhibitory effect of bacterial products on IL-2 production correlated with inhibition of mitogen-stimulated lymphocyte proliferation, although urease inhibited IL-2 production without inhibiting proliferation, suggesting that inhibition of IL-2 production alone is not sufficient to inhibit lymphocyte proliferation. The results of these studies demonstrate that Th1 polarization of the gastric immune response may be due in part to the direct effects of multiple different H. pylori components that enhance IFN-γ and IL-12 production while inhibiting both IL-2 production and cell proliferation that may be necessary for Th2 responses.

scholarly journals Protection against Cryptococcosis by Using a Murine Gamma Interferon-Producing Cryptococcus neoformans Strain

2007 ◽  
Vol 75 (3) ◽  
pp. 1453-1462 ◽  
Author(s):  
Floyd L. Wormley ◽  
John R. Perfect ◽  
Chad Steele ◽  
Gary M. Cox
Keyword(s):  
Immune Responses ◽  
Cryptococcus Neoformans ◽  
Pulmonary Infection ◽  
Cytokine Expression ◽  
Gamma Interferon ◽  
Host Immunity ◽  
Wild Type ◽  
Novel Method ◽  
Ifn Γ ◽  
Stimulation Of

ABSTRACT We evaluated cell-mediated immune (CMI) responses in mice given a pulmonary infection with a Cryptococcus neoformans strain engineered to produce the Th1-type cytokine gamma interferon (IFN-γ). Mice given a pulmonary infection with an IFN-γ-producing C. neoformans strain were able to resolve the primary infection and demonstrated complete (100%) protection against a second pulmonary challenge with a pathogenic C. neoformans strain. Pulmonary cytokine analyses showed that Th1-type/proinflammatory cytokine and chemokine expression were significantly higher and Th2-type cytokine expression was significantly lower in mice infected with the IFN-γ-producing C. neoformans strain compared to wild-type-infected mice. This increased pulmonary Th1-type cytokine expression was also associated with significantly lower pulmonary fungal burden and significantly higher pulmonary leukocyte and T-lymphocyte recruitment in mice infected with the IFN-γ-producing C. neoformans strain compared to wild-type-infected mice. Our results demonstrate that pulmonary infection of mice with a C. neoformans strain expressing IFN-γ results in the stimulation of local Th1-type anti-cryptococcal CMI responses and the development of protective host immunity against future pulmonary cryptococcal infections. The use of fungi engineered to produce host cytokines is a novel method to study immune responses to infection and may be useful in developing vaccine strategies in humans.

scholarly journals Human Immunodeficiency Virus (HIV)-Specific Gamma Interferon Secretion Directed against All Expressed HIV Genes: Relationship to Rate of CD4 Decline

2005 ◽  
Vol 79 (8) ◽  
pp. 4908-4917 ◽  
Author(s):  
Yoav Peretz ◽  
Galit Alter ◽  
Marie-Pierre Boisvert ◽  
George Hatzakis ◽  
Christos M. Tsoukas ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Immune Responses ◽  
Disease Progression ◽  
Mononuclear Cells ◽  
Gamma Interferon ◽  
Peripheral Blood Mononuclear ◽  
Slow Progressors ◽  
Immunodeficiency Virus ◽  
Ifn Γ

ABSTRACT Immune responses to human immunodeficiency virus (HIV) are detected at all stages of infection and are believed to be responsible for controlling viremia. This study seeks to determine whether gamma interferon (IFN-γ)-secreting HIV-specific T-cell responses influence disease progression as defined by the rate of CD4 decline. The study population consisted of 31 subjects naïve to antiretroviral therapy. All were monitored clinically for a median of 24 months after the time they were tested for HIV-specific responses. The rate of CD4+-T-cell loss was calculated for all participants from monthly CD4 counts. Within this population, 17 subjects were classified as typical progressors, 6 subjects were classified as fast progressors, and 8 subjects were classified as slow progressors. Peripheral blood mononuclear cells were screened for HIV-specific IFN-γ responses to all expressed HIV genes. Among the detected immune responses, 48% of the recognized peptides were encoded by Gag and 19% were encoded by Nef gene products. Neither the breadth nor the magnitude of HIV-specific responses correlated with the viral load or rate of CD4 decline. The breadth and magnitude of HIV-specific responses did not differ significantly among typical, fast, and slow progressors. These results support the conclusion that although diverse HIV-specific IFN-γ-secreting responses are mounted during the asymptomatic phase, these responses do not seem to modulate disease progression rates.

scholarly journals Optimal Blood Mononuclear Cell Isolation Procedures for Gamma Interferon Enzyme-Linked Immunospot Testing of Healthy Swedish and Tanzanian Subjects

2008 ◽  
Vol 15 (4) ◽  
pp. 585-589 ◽  
Author(s):  
C. Nilsson ◽  
S. Aboud ◽  
K. Karlén ◽  
B. Hejdeman ◽  
W. Urassa ◽  
...  
Keyword(s):  
Immune Responses ◽  
Cell Separation ◽  
Mononuclear Cells ◽  
Gradient Centrifugation ◽  
Vaccine Trial ◽  
Dar Es Salaam ◽  
Gamma Interferon ◽  
Preparation Technique ◽  
Cell Preparation ◽  
Ifn Γ

ABSTRACT Determination of antigen-specific T-cell responses is an important part of vaccine assessment. High levels of recovery, viability, and functionality of peripheral blood mononuclear cells (PBMCs) are essential for reliable assessment of cell-mediated immune responses. Here, we sought to find the cell preparation technique best suited for two clinical vaccine trial sites: Stockholm, Sweden, and Dar es Salaam, Tanzania. Standard Ficoll-Paque gradient centrifugation, BD Vacutainer cell preparation tube (CPT), and Greiner Bio-One LeucoSep tube techniques were tested. Cell yield and viability were recorded. Gamma interferon (IFN-γ) enzyme-linked immunospot (ELISPOT) testing was used to assess cell functionality. No differences in mean recovery or mean viability of fresh PBMCs were observed between Ficoll-Paque gradient centrifugation and CPT techniques as used in Stockholm. In Dar es Salaam, recovery of PBMCs isolated by use of the Ficoll-Paque gradient technique was higher than that seen with CPT (1.58 ± 0.6 versus 1.34 ± 0.4 million cells/ml of blood [P = 0.0469]), and the viability of PBMCs processed by Ficoll-Paque gradient was higher than that seen with CPT-purified cells (95.8% ± 2.3% versus 92.6% ± 4.8% [P = 0.0081]). Furthermore, LeucoSep cell separation gave higher levels of yield (1.10 ± 0.3 versus 0.92 ± 0.3 million cells/ml of blood [P = 0.0022]) and viability (95.7% ± 2.0% versus 93.4% ± 3.2% [P = 0.0012]) than Ficoll-Paque cell separation. The cells purified by the different techniques at the two sites performed equally well in IFN-γ ELISPOT assays. Both techniques generated cell preparations with excellent yield, viability, and functionality in Stockholm. In Dar es Salaam, CPT did not perform as well as Ficoll-Paque separation. In a subsequent comparison, LeucoSep performed better than Ficoll-Paque separation. Our findings emphasize the need for on-site assessment of PBMC purification techniques for optimal evaluation of cell-mediated immune responses.

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 Helicobacter pylori AlpA and AlpB Bind Host Laminin and Influence Gastric Inflammation in Gerbils

2011 ◽  
Vol 79 (8) ◽  
pp. 3106-3116 ◽  
Author(s):  
Olga A. Senkovich ◽  
Jun Yin ◽  
Viktoriya Ekshyyan ◽  
Carolyn Conant ◽  
James Traylor ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Wild Type Strain ◽  
Host Tissue ◽  
Gastric Epithelium ◽  
Gastric Tissue ◽  
Wild Type ◽  
Binding Ability ◽  
Content Type ◽  
H Pylori ◽  
Laminin Binding

ABSTRACTHelicobacter pyloripersistently colonizes humans, causing gastritis, ulcers, and gastric cancer. Adherence to the gastric epithelium has been shown to enhance inflammation, yet only a fewH. pyloriadhesins have been paired with targets in host tissue. ThealpABlocus has been reported to encode adhesins involved in adherence to human gastric tissue. We report that abrogation ofH. pyloriAlpA and AlpB reduces binding ofH. pylorito laminin while expression of plasmid-bornealpAoralpBconfers laminin-binding ability toEscherichia coli. AnH. pyloristrain lacking only AlpB is also deficient in laminin binding. Thus, we conclude that both AlpA and AlpB contribute toH. pylorilaminin binding. Contrary to expectations, theH. pyloriSS1 mutant deficient in AlpA and AlpB causes more severe inflammation than the isogenic wild-type strain in gerbils. Identification of laminin as the target of AlpA and AlpB will facilitate future investigations of host-pathogen interactions occurring duringH. pyloriinfection.

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