naNoLice

Effective vaccines against salmon lice have so far proven difficult to develop. However, we have data showing that polyvalent DNA vaccines can induce systemic and mucosal antibodies against salmon lice antigens after intramuscular (im) injection into Atlantic salmon. Antibody levels remain low, particularly in mucus, and uptake of plasmid DNA (pDNA) to the cells at the injection site is dependent on in vivo electroporation, which is not suitable for large-scale vaccination.  

In this project, we will address these challenges by encapsulating antigen-coding pDNA and mRNA into lipid nanoparticles (LNPs), which will be optimized for increased transfection and antigen expression in muscle cells of Atlantic salmon. A large number of LNPs will be tested in vivo, both with respect to improved transfection efficiency and to investigate how immunomodulators can affect the levels and duration of antigen expression and immune response. In complex organisms such as sea lice, most functions are performed by factors that have coinciding functions. Therefore, a polyvalent vaccine targeting multiple interacting antigens and mechanisms at the host-parasite interface will be formulated, using the optimized LNPs. The immunogenicity and protective efficacy of the vaccine will then be verified in vivo. In addition to the immediate benefits for Atlantic salmon farming, the project will provide fundamental insights into the immunology of fish and contribute to the development of synthetic systems for uptake of nucleic acid-based vaccines in aquaculture.