"Ixodes ricinus abundance and its infection prevalence with Borrelia burgdorferi s.l. (the Lyme disease agent) have led to an increased risk of human exposure to tick bites and Borrelia infection in Europe. Acaricide based control of this vector has caused serious repercussions, thus raising the importance for the development of anti-tick vaccines. My previous work has demonstrated that guinea pigs vaccinated with a salivary cystatin of Ixodes scapularis, the Lyme vector in the USA, are partially protected against tick blood feeding and that the same protein facilitates Borrelia transmission as well. I. ricinus cystatin ortho-/homologues are not studied yet, partially due to the limited genomic information for this tick. Hence, this study aims to enrich our knowledge of I. ricinus salivary transcripts by considering the entire complex tick lifecycle and by performing massive 454 pyrosequencing, a relatively novel, highly efficient and cost effective technology. In parallel, library screens will be carried out to identify I. ricinus secreted cystatins. Their tissue specificity and abundance will be estimated, while gene silencing will evaluate their contribution to tick feeding success. Recombinant cystatins will be 1) biochemically characterised for their inhibitory effect on different cysteine proteases and 2) tested for their role in vertebrate host immunomodulation/pathogen transmission. Next, vaccination studies will investigate their potential to provide protection against I. ricinus and/or Lyme disease transmission. Overall, the proposed project is expected to enhance my collaboration with the scientific community in the United States and Europe, thus promoting the transfer of knowledge and technology in the field of tick functional genomics. It is also expected to reveal novel candidate salivary antigens for anti-tick vaccine development and thus to contribute towards a concerted effort for the control of a vector borne disease in Europe."