Vaccination against Bm86 Homologues in Rabbits Does Not Impair Ixodes ricinus Feeding or Oviposition

PLoS One. 2015 Apr 28;10(4):e0123495. doi: 10.1371/journal.pone.0123495. eCollection 2014.

Abstract

Human tick-borne diseases that are transmitted by Ixodes ricinus, such as Lyme borreliosis and tick borne encephalitis, are on the rise in Europe. Diminishing I. ricinus populations in nature can reduce tick exposure to humans, and one way to do so is by developing an anti-vector vaccine against tick antigens. Currently, there is only one anti-vector vaccine available against ticks, which is a veterinary vaccine based on the tick antigen Bm86 in the gut of Rhipicephalus microplus. Bm86 vaccine formulations cause a reduction in the number of Rhipicephalus microplus ticks that successfully feed, i.e. lower engorgement weights and a decrease in the number of oviposited eggs. Furthermore, Bm86 vaccines reduce transmission of bovine Babesia spp. Previously two conserved Bm86 homologues in I. ricinus ticks, designated as Ir86-1 and Ir86-2, were described. Here we investigated the effect of a vaccine against recombinant Ir86-1, Ir86-2 or a combination of both on Ixodes ricinus feeding. Recombinant Ixodes ricinus Bm86 homologues were expressed in a Drosophila expression system and rabbits were immunized with rIr86-1, rIr86-2, a combination of both or ovalbumin as a control. Each animal was infested with 50 female adults and 50 male adults Ixodes ricinus and tick mortality, engorgement weights and egg mass were analyzed. Although serum IgG titers against rIr86 proteins were elicited, no effect was found on tick feeding between the rIr86 vaccinated animals and ovalbumin vaccinated animals. We conclude that vaccination against Bm86 homologues in Ixodes ricinus is not an effective approach to control Ixodes ricinus populations, despite the clear effects of Bm86 vaccination against Rhipicephalus microplus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens / genetics*
  • Antigens / immunology
  • Drosophila melanogaster / genetics
  • Female
  • Ixodes / drug effects*
  • Ixodes / genetics*
  • Ixodes / immunology
  • Male
  • Oviposition / drug effects
  • Rabbits / immunology
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology
  • Tick Infestations / prevention & control
  • Tick Infestations / veterinary*
  • Vaccination / methods
  • Vaccines / immunology*

Substances

  • Antigens
  • Recombinant Proteins
  • Vaccines

Grants and funding

JWH is a recipient of a VENI stipend (91611065) from the Netherlands Organization for Health Research and Development (ZonMw). This work was supported by funding from the European Union’s Seventh Programme for research, technological development and demonstration under grant agreement No. 602272 (project ANTIDotE). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.