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Brossard, Michel

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Brossard, Michel
Affiliation principale
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https://libra.unine.ch/handle/123456789/308

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  • Publication
    Accès libre
    A family of putative metalloproteases in the salivary glands of the tick Ixodes ricinus
    (2008)
    Decrem, Yves
    ;
    Beaufays, Jérôme
    ;
    Blasioli, Virginie
    ;
    Brossard, Michel 
    ;
    Vanhamme, Luc
    ;
    Godfroid, Edmond
    Ticks are obligate blood-feeding arachnids. During their long-lasting blood meal, they have to counteract the protective barriers and defense mechanisms of their host. These include tissue integrity, pain, hemostasis, and the inflammatory and immune reactions. Here, we describe a multigene family coding for five putative salivary metalloproteases induced during the blood meal of Ixodes ricinus. The evolutionary divergence inside the family was driven by positive Darwinian selection. This came together with individual variation of expression, functional heterogeneity, and antigenic diversification. Inhibition of the expression of some of these genes by RNA interference prevented completion of the tick blood meal and affected the ability of the tick saliva to interfere with host fibrinolysis. This family of proteins could therefore participate in the inhibition of wound healing after the tick bite, thereby facilitating the completion of the blood meal.
  • Publication
    Accès libre
    The impact of gene knock-down and vaccination against salivary metalloproteases on blood feeding and egg laying by Ixodes ricinus
    (2008)
    Decrem, Yves
    ;
    Mariller, Marcel
    ;
    Lahaye, Kathia
    ;
    Blasioli, Virginie
    ;
    Beaufays, Jérôme
    ;
    Boudjeltia, Karim Zouaoui
    ;
    Vanhaeverbeek, Michel
    ;
    Cérutti, Martine
    ;
    Brossard, Michel 
    ;
    Vanhamme, Luc
    ;
    Godfroid, Edmond
    Two cDNAs coding homologous putative metalloproteases (Metis 1 and Metis 2, expected molecular weights of 55.6 and 56.0 kDa, respectively) were identified from the hard tick Ixodes ricinus. The expression of Metis genes was induced in salivary glands during tick blood meal. RNA interference was used to assess the role of both Metis 1 and Metis 2 in tick feeding. It was found that salivary gland extracts lacking Metis 1–2 had a restricted ability to interfere with fibrinolysis. RNAi against Metis 1–2 also induced a high mortality rate. An immune reaction was raised in repeatedly bitten animals against Metis 1 and 2. Vaccination of hosts with the recombinant Metis 1 protein produced in a eukaryotic system partially interfered with completion of the blood meal. Although vaccination did not alter the survival rate or feeding time of ticks, their weight gain and oviposition rate were reduced. This will affect their reproductive fitness in the field. We believe this is the first report of an anti-tick vaccine trial using a metalloprotease derived from I. ricinus.