A Proof-of-Concept Study to Develop a Peptide-Based Vaccine against Salmon Lice Infestation in Atlantic Salmon ( Salmo salar L.)

• Published in: Vaccines
• Main Authors: Amritha Johny, Pedro Ilardi, Rolf Erik Olsen, Bjørg Egelandsdal, Erik Slinde
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2024
• Subjects: Lepeophtheirus salmonis; Caligus rogercresseyi; fish parasite; blood feeding; peptide epitope; LC-MS/MS; Medicine; R; Atlantic salmon; Salmo salar
• Online Access: https://doi.org/10.3390/vaccines12050456; https://doaj.org/article/fb827666b0af4b7898b7e55a2b5b3a0a

Proteins present in blood samples from Atlantic salmon ( Salmo salar ) infected with salmon lice ( Lepeophtheirus salmonis ) were analyzed using liquid chromatography–high-resolution mass spectrometry. Bioinformatic analyses revealed 1820 proteins, of which 58 were assigned to lice. Among these, peroxiredoxin-2, an antioxidant protein, was found relevant with respect to blood feeding of the parasite. The three-dimensional structure analysis of the protein revealed a surface amino acid sequence of interest. A 13-amino-acid peptide was selected as a potential antigen due to its predicted solubility, antigenicity, probable non-allergenic, and non-toxic nature. This peroxiredoxin-2-derived peptide was synthesized, combined with a commercially available adjuvant, and used for vaccination. The test vaccine demonstrated a 60–70% protection rate against early-stage Lepeophtheirus salmonis infection in a challenge trial in Norway. Additionally, the vaccine was tested against salmon lice ( Caligus rogercresseyi ) in Chile, where a remarkable 92% reduction in the number of adult lice was observed. Thus, in combination with the selected adjuvant, the peptide showed antigenic potential, making it a suitable candidate for future vaccine development. The approach described holds promise for the development of peptide vaccines against various ectoparasites feeding on blood or skin secretions of their hosts.