| 1. |
- Adamsson, Jenni, 1977, et al.
(författare)
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Gastric expression of IL-17A and IFNγ in Helicobacter pylori infected individuals is related to symptoms
- 2017
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Ingår i: Cytokine. - : Elsevier BV. - 1043-4666. ; 99, s. 30-34
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Tidskriftsartikel (refereegranskat)abstract
- Background: Chronic infection with Helicobacter pylori leads to gastritis and in a subpopulation of infected individuals to ulcers and cancer. Bacterial virulence factors and host immune inflammatory responses are risk factors related to disease. CD4+ T cells secrete cytokines that promote inflammation and an anti-bacterial response in the gastric mucosa during infection. The aim of the study was to investigate the pattern of expression of CD4+ T cell derived cytokines, IL-17A and IFNγ in paired antrum and corpus biopsies and correlate it to H. pylori infection outcome. Methods: Gene and protein expression of IL-17A and IFNγ was analyzed in gastric biopsies from H. pylori infected subjects with non-ulcer dyspepsia (NUD) or gastric ulcer; and for comparison uninfected individuals. Results: Upregulation of IL-17A and IFNγ gene expression was seen in corpus and antrum biopsies of H. pylori infected individuals with NUD compared to in uninfected controls. The expression of these cytokines correlated significantly with each other. Immunofluorescence staining revealed increased frequencies of IL-17A+ and IFNγ+ cells in antrum biopsies of gastric ulcer patients compared to of H. pylori infected NUD individuals; positive cells were not detected in any of the biopsies of uninfected controls. The frequencies of IFNγ and IL-17A+ cells correlated positively with inflammation in the antrum, but not the corpus, of H. pylori infected individuals. In the antrum, while there was no significant evidence of correlation between IFNγ and bacterial score, a positive correlation between bacterial score and IL-17A+ cells was seen. Conclusions: In H. pylori infected individuals, the frequencies of IFNγ and IL-17A+ cells were increased in the antrum, particularly in patients with H. pylori induced gastric ulcers. Even though H. pylori colonized both the corpus and antrum regions of the stomach, the cytokine responses and subsequent pathology were mainly detected in the antrum. © 2017 Elsevier Ltd
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| 2. |
- Camponeschi, Alessandro, et al.
(författare)
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Dissecting Integrin Expression and Function on Memory B Cells in Mice and Humans in Autoimmunity.
- 2019
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Ingår i: Frontiers in immunology. - : Frontiers Media SA. - 1664-3224. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Immunological memory ensures life-long protection against previously encountered pathogens, and in mice and humans the spleen is an important reservoir for long-lived memory B cells (MBCs). It is well-established that integrins play several crucial roles in lymphocyte survival and trafficking, but their involvement in the retention of MBCs in secondary lymphoid organs, and differences between B cell subsets in their adhesion capacity to ICAM-1 and/or VCAM-1 have not yet been confirmed. Here, we use an autoimmune mouse model, where MBCs are abundant, to show that the highest levels of LFA-1 and VLA-4 amongst B cells are found on MBCs. In vivo blockade of VLA-4 alone or in combination with LFA-1, but not LFA-1 alone, causes a release of MBCs from the spleen into the blood stream. In humans, we find that in peripheral blood, spleens, and tonsils from healthy donors the highest expression levels of the integrins LFA-1 and VLA-4 are also found on MBCs. Consistent with this, we found MBCs to have a higher capacity to adhere to ICAM-1 and VCAM-1 than naïve B cells. In patients with the autoimmune disease rheumatoid arthritis, it is the MBCs that have the highest levels of LFA-1 and VLA-4; moreover, compared with healthy donors, naïve B and MBCs of patients receiving anti-TNF medication have enhanced levels of the active form of LFA-1. Commensurate levels of the active αL subunit can be induced on B cells from healthy donors by exposure to the integrin ligands. Thus, our findings establish the selective use of the integrins LFA-1 and VLA-4 in the localization and adhesion of MBCs in both mice and humans.
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| 3. |
- Sjökvist Ottsjö, Louise, 1986, et al.
(författare)
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A double mutant heat-labile toxin from Escherichia coli, LT(R192G/L211A), is an effective mucosal adjuvant for vaccination against Helicobacter pylori infection.
- 2013
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Ingår i: Infection and immunity. - 1098-5522. ; 81:5, s. 1532-40
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Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori infection 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 against H. pylori infection is available to date. In mice, mucosal vaccination with H. pylori antigens when given together with cholera toxin (CT) adjuvant, but not without adjuvant, can induce protective immune responses against H. pylori infection. However, the toxicity of CT precludes its use as a mucosal adjuvant in humans. We evaluated a recently developed, essentially nontoxic double mutant Escherichia coli heat-labile toxin, LT(R192G/L211A) (dmLT), as a mucosal adjuvant in an experimental H. pylori vaccine and compared it to CT in promoting immune responses and protection against H. pylori infection in mice. Immunization via the sublingual or intragastric route with H. pylori lysate 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 enhanced in vitro proliferative and cytokine responses from spleen and mesenteric lymph node cells to H. pylori antigens. Our results suggest that dmLT is an attractive adjuvant for inclusion in a mucosal vaccine against H. pylori infection.
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| 4. |
- Sjökvist Ottsjö, Louise, 1986, et al.
(författare)
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Defining the Roles of IFN-gamma and IL-17A in Inflammation and Protection against Helicobacter pylori Infection
- 2015
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- CD4(+) T cells have been shown to be essential for vaccine-induced protection against Helicobacter pylori infection. However, the effector mechanisms leading to reductions in the gastric bacterial loads of vaccinated mice remain unclear. We have investigated the function of IFN-gamma and IL-17A for vaccine-induced protection and inflammation (gastritis) using IFN-gamma-gene-knockout (IFN-gamma(-/-)) mice, after sublingual or intragastric immunization with H. pylori lysate antigens and cholera toxin. Bacteria were enumerated in the stomachs of mice and related to the gastritis score and cellular immune responses. We report that sublingually and intragastrically immunized IFN-gamma(-/-) mice had significantly reduced bacterial loads similar to immunized wild-type mice compared to respective unimmunized infection controls. The reduction in bacterial loads in sublingually and intragastrically immunized IFN-gamma(-/-) mice was associated with significantly higher levels of IL-17A in stomach extracts and lower gastritis scores compared with immunized wild-type mice. To study the role of IL-17A for vaccine-induced protection in sublingually immunized IFN-gamma(-/-) mice, IL-17A was neutralized in vivo at the time of infection. Remarkably, the neutralization of IL-17A in sublingually immunized IFN-gamma(-/-) mice completely abolished protection against H. pylori infection and the mild gastritis. In summary, our results suggest that IFN-gamma responses in the stomach of sublingually immunized mice promote vaccine-induced gastritis, after infection with H. pylori but that IL-17A primarily functions to reduce the bacterial load.
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| 5. |
- Sjökvist Ottsjö, Louise, 1986, et al.
(författare)
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Induction of mucosal immune responses against Helicobacter pylori infection after sublingual and intragastric route of immunization
- 2017
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Ingår i: Immunology. - : Wiley. - 0019-2805. ; 150:2, s. 172-183
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Tidskriftsartikel (refereegranskat)abstract
- There is a current lack of effective mucosal vaccines against major gastroenteric pathogens and particularly against Helicobacter pylori, which causes a chronic infection that can lead to peptic ulcers and gastric cancer in a subpopulation of infected individuals. Mucosal CD4(+) T-cell responses have been shown to be essential for vaccine-induced protection against H. pylori infection. The current study addresses the influence of the adjuvant and site of mucosal immunization on early CD4(+) T-cell priming to H. pylori antigens. The vaccine formulation consisted of H. pylori lysate antigens and mucosal adjuvants, cholera toxin (CT) or a detoxified double-mutant heat-labile enterotoxin from Escherichia coli (dmLT), which were administered by either the sublingual or intragastric route. We report that in vitro, adjuvants CT and dmLT induce up-regulation of pro-inflammatory gene expression in purified dendritic cells and enhance the H. pylori-specific CD4(+) T-cell response including interleukin-17A (IL-17A), interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) secretion. In vivo, sublingual immunization led to an increased frequency of IL-17A(+), IFN-gamma(+) and TNF-alpha(+) secreting CD4(+) T cells in the cervical lymph nodes compared with in the mesenteric lymph nodes after intragastric immunization. Subsequently, IL-17A(+) cells were visualized in the stomach of sublingually immunized and challenged mice. In summary, our results suggest that addition of an adjuvant to the vaccine clearly activated dendritic cells, which in turn, enhanced CD4(+) T-cell cytokines IL-17A, IFN-gamma and TNF-alpha responses, particularly in the cervical lymph nodes after sublingual vaccination.
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| 6. |
- Sjökvist Ottsjö, Louise, 1986, et al.
(författare)
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The role of IL-17A and IFN gamma in vaccine-induced protection against Helicobacter pylori infection
- 2014
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Ingår i: Cytokine. - : Elsevier BV. - 1043-4666 .- 1096-0023. ; 70:1, s. 65-65
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Konferensbidrag (refereegranskat)abstract
- The aim of the project was to evaluate mechanisms of vaccine-induced protection against Helicobacter pylori infection in mice. In particular, to elucidate the role of cytokines induced by H. pylori infection in promoting the protective or pathogenic immune responses in the stomach. Our group has previously shown that sublingual (SL; under the tongue) vaccination with H. pylori antigens and cholera toxin as an adjuvant was efficient in reducing the bacterial load in the stomach of mice with enhanced IFNγ and IL-17A responses in the stomach compared to unvaccinated mice. Using gene knockout mice and neutralizing antibodies, the impact of cytokines IFNγ and IL-17A on the bacterial load, immune responses and gastric inflammation was addressed. We report that after SL vaccination, IFNγ gene knockout (IFNγ−/−) mice were protected against H. pylori infection and had elevated IL-17A production and lower inflammation scores in the stomach compared to vaccinated wild-type mice. Furthermore, in vivo neutralization of IL-17A in sublingually vaccinated IFNγ−/−mice totally abrogated protection against H. pylori infection. We next examined the mechanisms for induction and maintenance of IL −17A after SL vaccination by studying the role of cytokines IL−1β and IL-23 using gene knockout mice either lacking IL-1 signaling or IL-23 production respectively. Our results show that after SL vaccination with H. pylori antigens and cholera toxin, IL-23p19−/− mice, but not IL-1RI−/− mice were protected against H. pylori infection. Gastric IL-17A responses could not be induced after challenge in the absence of IL-1 signaling, but could be maintained in the absence of IL-23. In summary, we report that IL-17A is important in reducing the bacterial load on the stomach of vaccinated mice which is dependent on intact IL-1 signaling, while IFNγ may promote inflammation. Based on our results, mechanisms of vaccine-induced protection against H. pylori infection and the role of specific cytokines will be discussed.
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