How to get rid of a pathobiontic bacterium from the stomach mucosa : role of inflammatory monocytes and IL-22 in the vaccine-induced reduction of helicobacter infection

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Demande d'une copie
ID Serval
serval:BIB_5DB8E69F9C31
Type
Thèse: thèse de doctorat.
Collection
Publications
Institution
Titre
How to get rid of a pathobiontic bacterium from the stomach mucosa : role of inflammatory monocytes and IL-22 in the vaccine-induced reduction of helicobacter infection
Auteur(s)
Moyat M.
Directeur(s)
Velin D.
Détails de l'institution
Université de Lausanne, Faculté de biologie et médecine
Adresse
Faculté de biologie et de médecineUniversité de LausanneCH-1015 LausanneSUISSE
Statut éditorial
Acceptée
Date de publication
2015
Langue
anglais
Nombre de pages
145
Résumé
Helicobacter pylori is a bacterium colonizing the human stomach. To prevent or cure this potentially detrimental infection, vaccination might be a suitable alternative to antibiotic therapies. Recently, a study has demonstrated that a vaccine efficiently prevented H pylori infection in human. However, the mechanisms leading to protection remain elusive. In mice, the vaccine-induced protective response relies on CD4+ T cells and especially on Thl7 response. Nevertheless, the factors mediating the reduction of H pylori infection are not fully characterized. Hence, the aim of my thesis was to characterize the factors associated with the Thl7 response. In the context of the vaccine-induced reduction of Helicobacter infection, I first focused on the role of inflammatory monocytes. I showed that CDllb+Ly6CLOW inflammatory monocytes accumulated in the stomach of vaccinated mice in association with the reduction of Helicobacter infection. Remarkably, the depletion of inflammatory monocytes delayed the vaccine-induced protective response. Concerning the role of these cells, I demonstrated that inflammatory monocytes extracted from the stomach of vaccinated mice produced iNOS and killed H pylori in vitro. In a next step, I evaluated the role of IL-22 during the vaccine-induced response. IL-22, which is linked to the Thl7 response, increases innate defense mechanisms of epithelial cells. I demonstrated that IL-22 produced by antigen- specific Thl7 was increased in the stomach of vaccinated mice during the protective response. Interestingly, neutralization of IL-22 was associated with an impaired vaccine-induced protective response. Then, I demonstrated that IL-22 induced antimicrobial peptides (AMPs) secretion by epithelial cells. These AMPs killed H pylori in vitro. In conclusion, I showed that both inflammatory monocytes and IL-22 participated to the vaccine induced reduction of Helicobacter infection. In addition, I demonstrated that the epithelium along with inflammation induced by Thl7 response is a critical factor mediating reduction of Helicobacter infection.
Création de la notice
07/03/2016 10:56
Dernière modification de la notice
20/08/2019 14:15
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