Development of a mucosally-delivered and active salmon louse vaccine for Atlantic salmon aquaculture

This project is a collaboration between IoA, Moredun Research Institute and two industrial partners. No effective vaccines are commercially available for L. salmonis, and developing vaccines against this parasite has been challenging. Appropriate vaccine targets are those that impact parasite attachment, development and/or maturation and which are present during parasitic stages of their life cycle. Vaccination against other ectoparasites of livestock, namely tropical cattle ticks, using recombinant proteins, has previously resulted in a commercially-available vaccine (TickGARD), demonstrating the potential for this approach. Our approach will use Reverse Vaccinology (RV) which involves, amongst other elements, the use of bioinformatics tools to screen the predicted proteome of the target species to identify suitable target antigens. Once putative vaccine targets are identified, recombinant proteins can be expressed and further characterised through in vivo efficacy screening for early antigen discovery. Vaccine targets are initially identified using in silico algorithms predicting open reading frames (ORFs) of surface, membrane or secreted proteins from whole genomes. Significant progress has been made in the use of RV approaches to develop vaccines against the tropical cattle tick (Rhipicephalus microplus) and the Australian paralysis tick (Ixodes holocyclus). A complete, assembled, annotated genome is the preferred starting point for reverse vaccinology and six salmon louse genome assemblies are currently available. In this project we will develop and screen vaccines using a RV approach followed by sea lice challenge trials which also assess the optimal methods for vaccine delivery. The work will also explore the use of adjuvants better suited for eliciting a mucosal and anti-parasitic response.