Complex interactions between host macrophages and pathogens

Zeit : Mittwoch , 11:00 Uhr
Veranstalter : Institut für Molekulare Endokrinologie der Tiere
Ort : Universität Ulm, N25/H9, H9

Jacques ROBERT, Ph. D. Professor of Microbiology and Immunology

Director of the Xenopus laevis Research Resource for Immunobiology

Department of Microbiology & Immunology

University of Rochester

Medical Center Rochester

New York, USA

 

“Complex interactions between host macrophages and pathogens”

Macrophages are central in host/microbial pathogen interactions. They serve as sentinel providing a first line of defense against infection and activate adaptive immune response. However, macrophages are also often targeted by pathogens to evade immune response and persist in the host. We have established a reliable infection model system in the amphibian Xenopus laevis for investigating in vivo the complex roles of different macrophage populations of adult frogs and tadpoles during infection by the pox-like ranavirus FV3. Our study reveals that macrophages are required for tadpole and adult frog resistance to FV3 and that the antiviral state of macrophage is promoted by IL-34 stimulation through the CSF-1 receptor. However, peritoneal macrophages disseminate FV3 infection in the tadpole brain and harbor quiescent virus that can be reactivated by inflammation in asymptomatic adult frogs.

Furthermore, using X. laevis transgenic lines expressing fluorescent reporter genes under the control of myeloid (lurp) and macrophage (mpeg)-specific promoters we have also adapted our model to visualize intravitally macrophage activity during Mycobacteria marinum (Mm) infection. Notably, in combination with fluorescently labeled recombinant Mm, we have been able to detect Mm-infected macrophages at the site of infection in the muscle tail and follow Mm dissemination to other organs such as liver and lung.

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