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
Détails

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
Directeur⸱rice⸱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