Viraemia vaccination to protect fish
Common carp is worldwide the most cultured fish species for food consumption. Cyprinus carpio koi, the ornamental variety of common carp, is an extremely expensive pet used mainly for decorative purposes. Unfortunately, the lack of health guidelines and certification, has led to the rapid spread of the deadly disease SVC.Although anti-viral remedies and quarantine measures may in certain cases limit the spread of SVC disease, drug resistance could limit the efficacy of most drugs. As a result, alternative approaches such as vaccination are being considered.The approach of the EU-funded ′Improving vaccination of carp against spring viraemia of carp virus (SVCV)′ project was based on IFNs. IFN's are cytokine molecules central to immune cell interplay in response to pathogens. The idea was to use fish IFNs as molecular adjuvants to improve vaccination outcome against the SVC virus (SVCV).To this end, scientists characterised the fish IFN genes and their in vivo expression levels during SVCV infection. To test their antiviral activity in vitro, these genes were cloned into a single vector and expressed in SVCV infected cells. Co-administration of recombinant IFNs alongside a DNA vaccine using the glycoprotein G gene – the most immunogenic part of SVCV – illustrated superior protection against the virus challenge.Although still at an experimental level, the SVCV study demonstrated as proof of principle that IFNs are capable of reinforcing immune responses against viral infection. IFN-based vaccines can thus help prevent infectious viral diseases in fish, thus benefitting aquaculture and ornamental fish trading industries.
Keywords
Spring Viraemia of Carp, interferons, vaccine, common carp, virus, glycoprotein, recombinant
