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Interactions filaire/poumon dans le modèle murin de filariose Litosomoides sigmodontis

Abstract : Filariae are parasitic nematodes transmited to vertebrates by haematophagous arthropods. The filarial species that settle in the coelomic cavities, the lymphatic vessels or the connective tissues have their infectious stages (or L3) which migrate via the lymphatic system after their inoculation into the skin. Using the murine model with the filaria Litomosoides sigmodontis, whose adults reside in the pleural cavity, two phases of interaction between filariae and the lung of BALB/c mice are described 1) during the L3 migration from the skin to the pleural cavity ; 2) during the patent phase of infection, when adults realease microfilariae in the pleural cavity. During the 1st phase L3 join the pulmonary blood system and then cross through the lungs to enter the pleural cavity. This passage induces a transient acute pathology: first haemorrhages following the rupture of the pulmonary capillaries, together with an increase in the number of pulmonary neutrophils and the transient release of IL-1β and the alarmins IL-33 and S100A9 in the pleural cavity. S100A9 appears to facilitate the survival of the filariae either by an anti-inflammatory effect or by facilitating the migration of L3. Neutrophils can release NETs in response to L3. Within days following the infection, a regulatory response takes place in the lungs, with recruitment of macrophages and eosinophils, production of IL-4, CCL2 and IL-9, and downregulation of inflammatory molecules. The formation of granulomas is also observed in pulmonary tissue. The passage of L3 also induces an inflammation of pulmonary blood vessels, in C57BL/6 mice only. During the patent phase of the infection, 40% of the mice do not develop blood microfilaraemia. Comparison of responses of microfilaremic and amicrofilaremic mice shows an exacerbation of pleural inflammation induced by microfilariae. In addition, microfilaremic mice develop microfilaria-dependent pulmonary pathology consisting on fibrosis of the visceral pleura, perivascular accumulation of macrophages and bronchoalveolar inflammation (mucus production and eosinophilia). The control of the filariae (adults and microfilariae), but also the establishment of the pathology are dependent on IL-5 and IL-4R.
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https://tel.archives-ouvertes.fr/tel-01884175
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Submitted on : Sunday, September 30, 2018 - 1:03:51 AM
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  • HAL Id : tel-01884175, version 1

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STAR | CNRS | MNHN

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Frédéric Fercoq. Interactions filaire/poumon dans le modèle murin de filariose Litosomoides sigmodontis. Parasitologie. Museum national d'histoire naturelle - MNHN PARIS, 2017. Français. ⟨NNT : 2017MNHN0018⟩. ⟨tel-01884175⟩

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