title: Protective immunity against Ixodes ricinus induced by a salivary serpin.
abstract: Iris is a specific elastase inhibitor expressed in the salivary glands of the hard tick Ixodes ricinus. It belongs to the superfamily of serpins and interferes with both haemostasis and the immune response of the host. In this study, we first show that Iris is expressed in nymphs but not in the female midgut nor in males. We also show that Iris is present in the saliva. To examine its potency as anti-tick vaccine candidate, we set up three models of I. ricinus infestation on immunized animals: nymphs on mice, and adults and nymphs on rabbits. We report the rise of neutralizing antibodies following immunization of rabbits and mice. This comes with a significant protective immunity against ticks in rabbits only, resulting in a 30% mortality rate and a diminution of weight gain in both nymphs and adults and a prolongation of blood feeding time in adults. This is the first report on an anti-tick vaccine trial on I. ricinus using a protein able to interact with both host immunity and haemostasis, as a vaccinating antigen.
authors.affiliation: Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, Rue des Professeurs Jeener et Brachet, 12, B-6041 Gosselies, Belgium.
authors.forename: P-P
authors.initials: PP
authors.lastname: Prevot
authors.forename: B
authors.initials: B
authors.lastname: Couvreur
authors.forename: V
authors.initials: V
authors.lastname: Denis
authors.forename: M
authors.initials: M
authors.lastname: Brossard
authors.forename: L
authors.initials: L
authors.lastname: Vanhamme
authors.forename: E
authors.initials: E
authors.lastname: Godfroid
mesh_terms: D000818:Animals; D015153:Blotting, Western; D005260:Female; D007074:Immunoglobulin G / Q000097:blood; D018884:Ixodes / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011817:Rabbits; D015843:Serpins / Q000032:analysis / Q000276:immunology*; D013984:Tick Infestations / Q000517:prevention & control*; D014611:Vaccination
chemical_list: D007074:Immunoglobulin G; C515507:Iris protein, Ixodes ricinus; D015843:Serpins