Alternatives to mineral oil adjuvants in vaccines against Aeromonas salmonicida subsp. salmonicida in rainbow trout offer reductions in adverse effects

• Published in: Scientific reports 2017-07, Vol.7 (1), p.5930-15, Article 5930
• Main Authors: Villumsen, Kasper Rømer, Koppang, Erling Olaf, Christensen, Dennis, Bojesen, Anders Miki
• Format: Article
• Language: English
• Subjects: 14/63; 631/154/1438; 631/250/590/2291; 64; 692/420/2780/2152; Adjuvants; Adjuvants, Immunologic - pharmacology; Aeromonas salmonicida; Aeromonas salmonicida - drug effects; Aeromonas salmonicida - physiology; Animals; Condition factor; CpG islands; Experimental infection; Female; Fish; Fish Diseases - immunology; Fish Diseases - microbiology; Fish Diseases - pathology; Fish oils; Gram-Negative Bacterial Infections - immunology; Gram-Negative Bacterial Infections - microbiology; Gram-Negative Bacterial Infections - pathology; Humanities and Social Sciences; Mineral Oil - pharmacology; Mineral oils; multidisciplinary; Oligonucleotides; Oncorhynchus mykiss; Oncorhynchus mykiss - virology; Salmon; Science; Science (multidisciplinary); Side effects; Survival Analysis; Trout; Vaccination; Vaccines; Vaccines - immunology
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-06324-7

In an effort to reduce the frequency and severity of adverse reactions seen from the use of mineral oil adjuvants in salmonid fish, the effects of two alternative adjuvants were assessed, focusing on the induction of adverse effects as well as protection. Using rainbow trout ( Oncorhynchus mykiss ) as recipients, injection vaccines based on formalin-inactivated Aeromonas salmonicida subspecies salmonicida were formulated with CpG oligodeoxynucleotides, the liposomal cationic adjuvant formulation 01 (CAF01) or with Freund’s incomplete adjuvant and administered intraperitoneally. Control groups of unvaccinated, Tris-buffered saline-injected or bacterin-injected individuals were included, and each group included in the study held a total number of 240 individuals. Subsequently, individuals from each group were examined for differences in Fulton’s condition factor, macro- and microscopic pathological changes, as well as protection against experimental infection with A. salmonicida . While adverse effects were not eliminated, reductions in microscopic and macroscopic adverse effects, in particular, were seen for both the nucleotide- and liposome-based vaccine formulations. Furthermore, the induced protection appears similar to that of the benchmark formulation, thus introducing viable, potential alternative types of adjuvants for use in future fish vaccines.