A new generation of adjuvants for salmon vaccines emerges
Chilean scientists have demonstrated that peptides derived from NK-lysine and HMGB1 improve the immune response in salmon vaccinated against infectious pancreatic necrosis virus (IPNV), paving the way for more effective formulations.
Published
Vaccines are a crucial method for preventing infectious diseases and improving fish health; however, these immunological products still have limited effectiveness against some important pathogens.
Adjuvants play a key role in vaccines by enhancing their ability to generate an effective immune response. They work by modulating the immune system, which not only increases vaccine efficacy but also directs the desired response.
Among the emerging adjuvants which have proven to be promising candidates as molecular adjuvants in the development of fish vaccines, immunomodulatory peptides, such as NK-lysine and peptides derived from the HMGB1 (High Mobility Group Box 1) protein, stand out.
IPNV antigen
In a newly published study, a group of Chilean scientists from the University of Concepción, the Austral University of Chile, the Incar Centre, and salmon farmer Mowi Chile evaluated the adjuvant potential of immunomodulatory peptides derived from HMGB1 (11W) and NK-lysine (NK1 and NK4) in formulations containing the IPNV VP2 antigen.
To do this, the researchers co-administered the peptides with the recombinant VP2 protein by intraperitoneal injection in different experimental groups of Atlantic salmon and subsequently analysed serum samples to determine IgM levels. (Editor's note: IgM is the first antibody to appear in the response to initial exposure to an antigen).
In addition, the scientists used RT-qPCR to evaluate the induction of the cytokines IFN-γ, IL-17 and IL-4/13A in tissues and leukocytes of the head kidney restimulated with the antigen.
Stimulated antibodies
In their results, the researchers found that formulations containing NK1, NK4, and 11W progressively stimulated IgM production, starting on day 35 post-vaccination. "Furthermore, these adjuvant peptides significantly induced the expression of the cytokines evaluated in the head kidney and spleen of immunised animals, as well as in the primary culture model, suggesting the activation of Th1, Th2, and Th17 responses," the scientists detailed.
With these findings, the researchers noted that peptide adjuvants can enhance the immune response in salmonid vaccination, "offering a promising alternative to conventional adjuvants".
Read the abstract of the study titled “Evaluating the adjuvant potential of NK-lysin and HMGB1-derived peptides in enhancing immune responses in Salmo salar”, here.
