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Theses

Etude des interactions entre les cellules dendritiques pulmonaires murines et Bacillus anthracis

Abstract : Bacillus anthracis is a Gram positive bacterium and produces two critical virulence factors, two toxins (the lethal toxin (LT) and the edema toxin (ET)); and a capsule. We study the migration of different murine pulmonary cell populations during the infection in vivo to investigate the cellular mechanisms leading to the entry of the pathogen and particularly how immobile spores are captured in the alveoli and transported to the lymph nodes in the early steps of the infection. We have examined the role of the different lung phagocytic cell populations. We show that AMs are the first cells to phagocyte alveolar spores within 10 min. Interstitial lung dendritic cells (LDC) capture spores in the alveoli within 30 min without trans-migrating through the epithelial barrier. LDCs rapidly carry the spores to the thoracic lymph nodes within 30 minutes. The timing of infection observed here is very rapid and should be taken into account. To investigate the role of toxins in the physiopathology of inhalational anthrax, we evaluated the functions of LDC upon infection ex vivo. LT expressing strains down-regulate the expression of CD86 and MHC class II by LDC. The toxins secreted during the infection selectively inhibited the production of cytokines by LDC, and therefore suppress the innate immune response. This may represent a new strategy developed by B. anthracis to escape the host response and spread through the alveolar wall.
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https://tel.archives-ouvertes.fr/tel-00139077
Contributor : Aurélie Cleret <>
Submitted on : Thursday, March 29, 2007 - 11:07:46 AM
Last modification on : Thursday, March 29, 2007 - 1:26:26 PM
Long-term archiving on: : Friday, November 25, 2016 - 3:33:44 PM

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  • HAL Id : tel-00139077, version 1

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Aurélie Cleret. Etude des interactions entre les cellules dendritiques pulmonaires murines et Bacillus anthracis. Immunologie. Université Joseph-Fourier - Grenoble I, 2007. Français. ⟨tel-00139077⟩

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