- Email: [email protected]
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Abstract / Cytokine 70 (2014) 28–79 194 Leptin and IL-17 mediated responses in vaccination against Helicobacter pylori Dorit Becher 1,1, Jacinta Ortega 2, Sukanya Raghavan 3, Louise Sjökvist Ottsjo 3, Odilia Wijburg 1, Richard Strugnell 1, Anna K. Walduck 2, 1 Microbiology and Immunology, University of Melbourne, Melbourne, Victoria, Australia, 2 Biosciences Discipline, RMIT University, Melbourne, Victoria, Australia, 3 Microbiology and Immunology, University of Gothenburg, Gothenburg, Sweden
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tment, and was associated with a reduction of plasma levels IL-6, IL-8 and IL-10. Plasma concentrations of cAMP were significantly decreased in patients with ANS dysregulation or PE compared with patients with HFMD or BE, however, cAMP levels increased after milrinone treatment. Conclusions: These findings provided new insight into the role of regulatory T cells. Furthermore, CD4+ CD25+ Foxp3+ and cAMP expression might be related to the progression of severe EV71 infection, and its responses to milrinone treatment. http://dx.doi.org/10.1016/j.cyto.2014.07.202
Infection with Helicobacter pylori causes chronic inflammation and damage to the gastric epithelium. This leads to chronic gastritis, and in a proportion of patients, ulcer, or gastric cancer. Candidate H. pylori vaccines tested in volunteers to date have proved poorly immunogenic and/or to induce adverse reactions. Indeed there is some evidence that ‘‘post immunisation gastritis” occurs because the tightly controlled inflammatory response in the gastric mucosa is unbalanced [1]. Vaccination is effective in animal models, and CD4+ T cells, and both the adipokine leptin (Ob) [2] and interleukin 17 (IL-17) [3] have been show to be essential for vaccineinduced protection against H. pylori. Leptin is pro-inflammatory, and impacts CD4+ T cell, regulatory CD4+ T cell (Treg), and even neutrophil function. IL-17 promotes neutrophil recruitment into tissues, and inflammatory cytokine production by macrophages. Aims: To investigate the roles of leptin receptor (ObR) signalling and IL-17 in the vaccine- induced immune responses against H. pylori. Methods: We studied responses in vaccinated wild-type C57BL/6 and ObR-signalling deficient C57BL/6 CgObR db/db mice (db/db). Results: Vaccinated db/db mice are not protected from H. pylori challenge, we find also that gastric IL-17 production was reduced in these mice. In the stomachs of wild-type mice, both leptin and ObR are expressed on epithelial, CD4 + T cells, CD4 + Treg, macrophages and neutrophils. Further, bone marrow chimaera studies revealed that functional ObR on BM-derived cells was essential for vaccine- induced protection. Notably, Th17 cells in the gastric mucosa of vaccinated, protected WT mice also secrete leptin. Conclusions: Our data support a link between leptin and Th-17 responses in gastric inflammation. We hypothesise that T-cell derived leptin impacts both Treg function and IL-17 production, regulating protective responses in the vaccinated stomach.
References [1] Walduck AK, Becher D. Leptin, CD4+ Treg and the prospects for vaccination against H. pylori infection. Front Immunol 2012;3:1–8. [2] Wehrens A, Aebischer T, Meyer TF, Walduck AK. Leptin receptor signaling is required for vaccine-induced protection against Helicobacter pylori. Helicobacter 2008;13:94–102. [3] Flach C-F, Östberg AK, Nilsson A-T, Malefyt RDW, Raghavan S. Proinflammatory cytokine gene expression in the stomach correlates with vaccine-induced protection against Helicobacter pylori infection in mice: an important role for interleukin-17 during the effector phase. Infect Immun 2011;79:879–86. http://dx.doi.org/10.1016/j.cyto.2014.07.201
195 Regulatory T cells and cyclic adenosine monophosphate in enterovirus 71 infection Shih-Min Wang 1, Ching-Chuan Liu 2, 1 Department of Emergency Medicine, College of Medicine, National Cheng Kung University and Hospital, Tainan, Taiwan, 2 Department of Pediatrics, College of Medicine, National Cheng Kung University and Hospital, Tainan, Taiwan Background: Since 1998, Taiwan has experienced several hand, foot, and mouth disease (HFMD) epidemics caused by enterovirus 71 (EV71). Two notable features of severe EV71 infection in young children are brainstem encephalitis (BE) and fatal pulmonary edema (PE). This study investigated the specific immunoregulatory characterizations of EV71 neurological complications according to the disease severity. Methods: Patients younger than 18 years with virologically confirmed EV71 infections were enrolled and divided into 2 groups: the HFMD or BE group, and the autonomic nervous system (ANS) dysregulation or PE group. Laboratory findings, cytokine and cyclic adenosine monophosphate (cAMP) levels, immunophenotypes, and the regulatory T cell (Tregs) profiles of the EV71-infected patients were determined. Results: Patients with ANS dysregulation or PE exhibited a significantly low frequency of CD4+ CD25+ Foxp3+ and CD4+ Foxp3+ T cells compared with patients with HFMD or BE. The expression frequency of CD4 CD8 was also significantly decreased in patients with ANS dysregulation or PE. Among patients with ANS dysregulation or PE, the expression frequency of CD4+ Foxp3+ increased markedly after milrinone trea1 Current address: GSK Ltd., Melbourne, Victoria, Australia.
196 Critical role for IL-33 in the onset and progression of experimental asthma induced by concomitant virus infection and allergen exposure Rhiannon B. Werder 1, Jason P. Lynch 1, Jennifer Simpson 1, Ken Loh 1, Vivian Zhang 1, Kirsten Spann 2,3, Peter D. Sly 3,4, Stuart Mazzone 1, John W. Upham 3,5, Simon Phipps 1,3, 1 University of Queensland, St. Lucia, QLD, Australia, 2 Sir Albert Sakzewski Virus Research Centre, Brisbane, QLD, Australia, 3 Australian Infectious Diseases Research Centre, Brisbane, QLD, Australia, 4 Queensland Children’s Medical Research Institute, Brisbane, QLD, Australia, 5 Lung and Allergy Research Centre, School of Medicine, University of Queensland Brisbane, QLD, Australia Frequent, severe wheezy lower respiratory tract viral infections and allergic sensitisation in early life are independently associated with the onset of asthma, and positively interact to markedly increase asthma risk. We have developed a model to interrogate this synergy by inoculating neonatal BALB/c mice with low dose pneumonia virus of mouse (PVM; 1pfu) then exposure to a submaximal dose of cockroach antigen (CRE, 1 lg) 3 days post infection (dpi). CRE exposure following viral infection reduced antiviral immunity (IFN-a, IFN-k, IL-12p40) and increased viral load in the airway epithelium. Moreover, plasmacytoid dendritic cells stimulated in vitro with CRE exhibited impaired antiviral function. Furthermore, co-exposure to PVM and CRE promoted type 2 inflammation (elevated IL33, recruitment of eosinophils and type 2 ILCs) and airway remodelling (airway smooth muscle and collagen deposition) at 10 dpi, compared with PVM infection alone. Immunoneutralisation of IL-33 prevented the induction of ILC2s, eosinophilia and importantly inhibited airway remodelling in co-exposed mice. Furthermore, exposure to CRE in early life significantly altered the immune response to the virus and allergen in reinfection. Asthma pathology (airway hyperresponsiveness, airway remodelling, eosinophilia, mast cell hyperplasia) following PVM reinfection (at day 49) and CRE challenge (at days 52, 59, 66 and 80) in later life was significantly elevated in co-exposed neonates. IL-33 blockade in primary and secondary infection significantly reduced all hallmark features of asthma. Our findings demonstrate that by reducing antiviral immunity, allergen exposure early in life increases viral load, and primes toward a Th2 response that drives the progression of asthma in reinfection. Furthermore, we highlight a critical role for IL33 underlying this virus-allergen synergy and are able to prevent disease onset by targeting this pathway.
http://dx.doi.org/10.1016/j.cyto.2014.07.203
197 The apoptotic caspase cascade suppresses mitochondrial DNA-induced STINGmediated type I IFN production by dying cells Michael J. White 1, Kate McArthur 1, Donald Metcalf 1, John Cambier 2, Sammy Bedoui 3, Matthew Ritchie 1, David C.S. Huang 1, Benjamin Kile 1, 1 The Walter and Eliza Hall Institute, Parkville, VIC, Australia, 2 University of Colorado School of Medicine, Denver, USA, 3 University of Melbourne, Melbourne, VIC, Australia Activated caspases are a hallmark of apoptosis induced by the intrinsic (mitochondrial) pathway, but they are ultimately dispensable for this form of programmed cell death, and for the apoptotic clearance of cells in vivo. Combined with emerging evidence that caspases can inactivate damage-associated molecular pattern molecules (DAMPs), this has led to the suggestion that caspases are primarily activated not to kill, but to prevent dying cells from triggering a host immune response. Here we show that activation of Bak and Bax, the essential mediators of the intrinsic apoptosis pathway, induces mitochondrial (mt) membrane permeabilisation that results in the efflux of mtDNA into the cytosol. Cytosolic mtDNA activates cGAS, which initiates STING-mediated type I interferon (IFN) production. Activation of the caspase cascade prevents IFN production. Disabling the caspase cascade by pharmacological inhibition or genetic deletion of Caspase-9, Apaf-1, or Caspase-3/7 triggers secretion of IFN-b by apoptotic cells. In vivo, this precipitates an elevation in IFN-b levels and consequent hematopoi-
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tment, and was associated with a reduction of plasma levels IL-6, IL-8 and IL-10. Plasma concentrations of cAMP were significantly decreased in patients with ANS dysregulation or PE compared with patients with HFMD or BE, however, cAMP levels increased after milrinone treatment. Conclusions: These findings provided new insight into the role of regulatory T cells. Furthermore, CD4+ CD25+ Foxp3+ and cAMP expression might be related to the progression of severe EV71 infection, and its responses to milrinone treatment. http://dx.doi.org/10.1016/j.cyto.2014.07.202
Infection with Helicobacter pylori causes chronic inflammation and damage to the gastric epithelium. This leads to chronic gastritis, and in a proportion of patients, ulcer, or gastric cancer. Candidate H. pylori vaccines tested in volunteers to date have proved poorly immunogenic and/or to induce adverse reactions. Indeed there is some evidence that ‘‘post immunisation gastritis” occurs because the tightly controlled inflammatory response in the gastric mucosa is unbalanced [1]. Vaccination is effective in animal models, and CD4+ T cells, and both the adipokine leptin (Ob) [2] and interleukin 17 (IL-17) [3] have been show to be essential for vaccineinduced protection against H. pylori. Leptin is pro-inflammatory, and impacts CD4+ T cell, regulatory CD4+ T cell (Treg), and even neutrophil function. IL-17 promotes neutrophil recruitment into tissues, and inflammatory cytokine production by macrophages. Aims: To investigate the roles of leptin receptor (ObR) signalling and IL-17 in the vaccine- induced immune responses against H. pylori. Methods: We studied responses in vaccinated wild-type C57BL/6 and ObR-signalling deficient C57BL/6 CgObR db/db mice (db/db). Results: Vaccinated db/db mice are not protected from H. pylori challenge, we find also that gastric IL-17 production was reduced in these mice. In the stomachs of wild-type mice, both leptin and ObR are expressed on epithelial, CD4 + T cells, CD4 + Treg, macrophages and neutrophils. Further, bone marrow chimaera studies revealed that functional ObR on BM-derived cells was essential for vaccine- induced protection. Notably, Th17 cells in the gastric mucosa of vaccinated, protected WT mice also secrete leptin. Conclusions: Our data support a link between leptin and Th-17 responses in gastric inflammation. We hypothesise that T-cell derived leptin impacts both Treg function and IL-17 production, regulating protective responses in the vaccinated stomach.
References [1] Walduck AK, Becher D. Leptin, CD4+ Treg and the prospects for vaccination against H. pylori infection. Front Immunol 2012;3:1–8. [2] Wehrens A, Aebischer T, Meyer TF, Walduck AK. Leptin receptor signaling is required for vaccine-induced protection against Helicobacter pylori. Helicobacter 2008;13:94–102. [3] Flach C-F, Östberg AK, Nilsson A-T, Malefyt RDW, Raghavan S. Proinflammatory cytokine gene expression in the stomach correlates with vaccine-induced protection against Helicobacter pylori infection in mice: an important role for interleukin-17 during the effector phase. Infect Immun 2011;79:879–86. http://dx.doi.org/10.1016/j.cyto.2014.07.201
195 Regulatory T cells and cyclic adenosine monophosphate in enterovirus 71 infection Shih-Min Wang 1, Ching-Chuan Liu 2, 1 Department of Emergency Medicine, College of Medicine, National Cheng Kung University and Hospital, Tainan, Taiwan, 2 Department of Pediatrics, College of Medicine, National Cheng Kung University and Hospital, Tainan, Taiwan Background: Since 1998, Taiwan has experienced several hand, foot, and mouth disease (HFMD) epidemics caused by enterovirus 71 (EV71). Two notable features of severe EV71 infection in young children are brainstem encephalitis (BE) and fatal pulmonary edema (PE). This study investigated the specific immunoregulatory characterizations of EV71 neurological complications according to the disease severity. Methods: Patients younger than 18 years with virologically confirmed EV71 infections were enrolled and divided into 2 groups: the HFMD or BE group, and the autonomic nervous system (ANS) dysregulation or PE group. Laboratory findings, cytokine and cyclic adenosine monophosphate (cAMP) levels, immunophenotypes, and the regulatory T cell (Tregs) profiles of the EV71-infected patients were determined. Results: Patients with ANS dysregulation or PE exhibited a significantly low frequency of CD4+ CD25+ Foxp3+ and CD4+ Foxp3+ T cells compared with patients with HFMD or BE. The expression frequency of CD4 CD8 was also significantly decreased in patients with ANS dysregulation or PE. Among patients with ANS dysregulation or PE, the expression frequency of CD4+ Foxp3+ increased markedly after milrinone trea1 Current address: GSK Ltd., Melbourne, Victoria, Australia.
196 Critical role for IL-33 in the onset and progression of experimental asthma induced by concomitant virus infection and allergen exposure Rhiannon B. Werder 1, Jason P. Lynch 1, Jennifer Simpson 1, Ken Loh 1, Vivian Zhang 1, Kirsten Spann 2,3, Peter D. Sly 3,4, Stuart Mazzone 1, John W. Upham 3,5, Simon Phipps 1,3, 1 University of Queensland, St. Lucia, QLD, Australia, 2 Sir Albert Sakzewski Virus Research Centre, Brisbane, QLD, Australia, 3 Australian Infectious Diseases Research Centre, Brisbane, QLD, Australia, 4 Queensland Children’s Medical Research Institute, Brisbane, QLD, Australia, 5 Lung and Allergy Research Centre, School of Medicine, University of Queensland Brisbane, QLD, Australia Frequent, severe wheezy lower respiratory tract viral infections and allergic sensitisation in early life are independently associated with the onset of asthma, and positively interact to markedly increase asthma risk. We have developed a model to interrogate this synergy by inoculating neonatal BALB/c mice with low dose pneumonia virus of mouse (PVM; 1pfu) then exposure to a submaximal dose of cockroach antigen (CRE, 1 lg) 3 days post infection (dpi). CRE exposure following viral infection reduced antiviral immunity (IFN-a, IFN-k, IL-12p40) and increased viral load in the airway epithelium. Moreover, plasmacytoid dendritic cells stimulated in vitro with CRE exhibited impaired antiviral function. Furthermore, co-exposure to PVM and CRE promoted type 2 inflammation (elevated IL33, recruitment of eosinophils and type 2 ILCs) and airway remodelling (airway smooth muscle and collagen deposition) at 10 dpi, compared with PVM infection alone. Immunoneutralisation of IL-33 prevented the induction of ILC2s, eosinophilia and importantly inhibited airway remodelling in co-exposed mice. Furthermore, exposure to CRE in early life significantly altered the immune response to the virus and allergen in reinfection. Asthma pathology (airway hyperresponsiveness, airway remodelling, eosinophilia, mast cell hyperplasia) following PVM reinfection (at day 49) and CRE challenge (at days 52, 59, 66 and 80) in later life was significantly elevated in co-exposed neonates. IL-33 blockade in primary and secondary infection significantly reduced all hallmark features of asthma. Our findings demonstrate that by reducing antiviral immunity, allergen exposure early in life increases viral load, and primes toward a Th2 response that drives the progression of asthma in reinfection. Furthermore, we highlight a critical role for IL33 underlying this virus-allergen synergy and are able to prevent disease onset by targeting this pathway.
http://dx.doi.org/10.1016/j.cyto.2014.07.203
197 The apoptotic caspase cascade suppresses mitochondrial DNA-induced STINGmediated type I IFN production by dying cells Michael J. White 1, Kate McArthur 1, Donald Metcalf 1, John Cambier 2, Sammy Bedoui 3, Matthew Ritchie 1, David C.S. Huang 1, Benjamin Kile 1, 1 The Walter and Eliza Hall Institute, Parkville, VIC, Australia, 2 University of Colorado School of Medicine, Denver, USA, 3 University of Melbourne, Melbourne, VIC, Australia Activated caspases are a hallmark of apoptosis induced by the intrinsic (mitochondrial) pathway, but they are ultimately dispensable for this form of programmed cell death, and for the apoptotic clearance of cells in vivo. Combined with emerging evidence that caspases can inactivate damage-associated molecular pattern molecules (DAMPs), this has led to the suggestion that caspases are primarily activated not to kill, but to prevent dying cells from triggering a host immune response. Here we show that activation of Bak and Bax, the essential mediators of the intrinsic apoptosis pathway, induces mitochondrial (mt) membrane permeabilisation that results in the efflux of mtDNA into the cytosol. Cytosolic mtDNA activates cGAS, which initiates STING-mediated type I interferon (IFN) production. Activation of the caspase cascade prevents IFN production. Disabling the caspase cascade by pharmacological inhibition or genetic deletion of Caspase-9, Apaf-1, or Caspase-3/7 triggers secretion of IFN-b by apoptotic cells. In vivo, this precipitates an elevation in IFN-b levels and consequent hematopoi-