Skip to Main content Skip to Navigation
New interface
Theses

Détection de la virulence bactérienne : caractérisation de la réponse immunitaire anti-virulence déclenchée par la toxine CNF1 d’Escherichia coli

Abstract : Our immune system detects microorganisms via molecules absent from the host called MAMPs. Since MAMPs are shared by all microorganisms regardless of their pathogenic potential, this mechanism does not explain how the immune system distinguishes between pathogenic and non pathogenic microorganisms. The detection of the activities of pathogen-encoded virulence factors has emerged as a new paradigm of pathogen recognition. Using Drosophila we previously demonstrated that the Escherichia coli CNF1 toxin-induced activation of the Rho GTPase Rac2 is sufficient to initiate a defense signal evolutionarily conserved from flies to mammals and similar to Effector-Triggered Immunity in plants. We further addressed the importance of this innate immune mechanism during bacteremia in mice and demonstrated the central role of the IL-1β cytokine in the clearance of bacteria in response to the detection of CNF1. In vitro experiments allowed us to identify the involved molecular mechanisms and the inflammasome responsible of caspase-1 activation and IL-1β maturation. Interestingly, CNF1 is always co-expressed with α-hemolysin toxin in pathogenic E. coli. In addition, we found that HlyA blocked the elimination of bacteria induced by CNF1 during bacteremia and inhibited the secretion of IL-1β. Here, we have reported the first example of immunity induced by a toxin (CNF1) and counteracted by another (HlyA).
Complete list of metadata

https://theses.hal.science/tel-03793796
Contributor : ABES STAR :  Contact
Submitted on : Sunday, October 2, 2022 - 1:05:32 AM
Last modification on : Sunday, October 2, 2022 - 3:45:51 AM

File

2017AZUR4071.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-03793796, version 1

Collections

Citation

Elsa Garcia. Détection de la virulence bactérienne : caractérisation de la réponse immunitaire anti-virulence déclenchée par la toxine CNF1 d’Escherichia coli. Sciences agricoles. COMUE Université Côte d'Azur (2015 - 2019), 2017. Français. ⟨NNT : 2017AZUR4071⟩. ⟨tel-03793796⟩

Share

Metrics

Record views

96

Files downloads

0