Correlates of protective immunity for fish vaccines

• Published in: Fish & shellfish immunology 2019-02, Vol.85, p.132-140
• Main Authors: Munang'andu, Hetron Mweemba, Evensen, Øystein
• Format: Article
• Language: English
• Subjects: Animals; Antibodies; Antibodies - immunology; Aquaculture; Correlates; Fish Diseases - immunology; Fish Diseases - prevention & control; Immunity; Protective; Salmonidae; Vaccination - veterinary; Vaccines; Vaccines - immunology
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2018.03.060

Vaccination is one of the most effective disease control strategies that has contributed to the significant reduction of disease outbreaks and antibiotics usage in salmonid aquaculture. To date, licensing of fish vaccines is to a limited extent based on in vitro correlates of protection, as done for many mammalian vaccines. This is because the immunological mechanisms of vaccine protection have not been clearly elucidated for most fish vaccines. Herein, we provide an overview of the different steps required to establish correlates of protective immunity required to serve as benchmarks in optimizing vaccine production in aquaculture. We highlight the importance of optimizing challenge models needed to generate consistent results used during vaccine development as a basis for establishing immune correlates of protection. Data generated this far shows that antibodies are potentially the most reliable correlates of protective immunity for fish vaccines. Our findings also show that antigen dose can be optimized to serve as a correlate of protection for fish vaccines. Further, there is need to establish signatures of T-cell protective immunity when antibodies fail to serve as proxies of immune protection, particularly for vaccines against intracellular pathogens. We can anticipate that documentation of efficacy for future vaccines in aquaculture, particularly batch testing will be based on in vitro correlates of protective immunity. •Optimization of challengemodels is important when developing correlates vaccine protection for finfishis important.•It is important that the measures of vaccine efficacy and immunological mechanisms of protection are established as a basis for establishing the correlates of vaccine protection.•Correlates of vaccineprotection in finfish are to a large extent based on antibody titers.•Antigen dose can beoptimized to serve as a correlate of vaccine protection in fish.•Gene expression can serveas surrogate marker of protective immunity for cellular mediated immunity.