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Abstract

How does the innate immune system recognize virulent microbes? And how do these microbes escape this immune response? Knowing that the pathogenic bacteria specifically express virulence factors, we looked for mechanisms able to detect the activity of these factors. Using models of Escherichia coli infection in both Drosophila and mice, we determined the importance of effector triggered immunity (ETI) in animals. We also found that a second bacterial factor HlyA counteracting ETI and allowing the ITU89 strain to be fully virulent. At the molecular level, our latest results in mice indicate that activation of the immune system involves the activation of caspase-1 and the recruitment of an inflammasome involving the ASC adapter to allow for the maturation of IL-1beta. Our work aims to determine the innate immune signaling as well as the molecular mechanism used by the pathogenic bacteria to block this immune response. Our long-term goal is to propose new strategies to stimulate host defense and detect AVI-deficient patients, which may be relevant for many infectious diseases.

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