Abstract
This work describes immunization of European sea bass (Dicentrarchus labrax) juveniles against viral nervous necrosis virus (VNNV), a betanodavirus causing worldwide mortalities in many fish species. Protection was obtained with the so-called spinycterin vehicles consisting of irreversibly DNA-damaged DNA-repair-less Escherichia coli displaying at their surface a downsized VNNV coat antigen. In this work we have (i) maximized bacterial expression levels by downsizing the coat protein of VNNV to a fragment (frgC91–220) containing most of its previously determined antigenicity, (ii) developed a scalable autoinduction culture media for E. coli based in soy-bean rather than in casein hydrolysates, (iii) enriched surface expression by screening different anchors from several prokaryotic sources (anchor + frgC91–220 recombinant products), (iv) preserved frgC91–220 antigenicity by inactivating bacteria by irreversible DNA-damage by means of Ciprofloxacin, and (v) increased safety using a repair-less E. coli strain as chassis for the spinycterins. These spinycterins protected fish against VNNV challenge with partial (Nmistic + frgC91–220) or total (YBEL + frgC91–220) levels of protection, in contrast to fish immunized with frgC91–220 spinycterins. The proposed spinycterin platform has high levels of environmental safety and cost effectiveness and required no adjuvants, thus providing potential to further develop VNNV vaccines for sustainable aquaculture.
Highlights
Viral encephalopathy and retinopathy cause up to 100% mortalities in juveniles of more than 40 finfish species including those most important to the European marine aquaculture industry such as sea bass (Dicentrarchus labrax) and sea bream (Sparus aurata) [1,2]. All these diseases are caused by viral nervous necrosis viruses (VNNVs) which belong to the Nodaviridae family within the betanodavirus genus [3,4]
To select an immunorelevant VNNV antigen for sea bass vaccination, the C-coat protein was chosen because it is the only target for fish neutralizing antibodies
Since targeted epitopes of both neutralizing monoclonal antibodies and serum samples from VNNV-infected survivor fish were mapped at amino acid positions 1–32, 91–162 and 181–212 [23,30], the fragment extending from the 91 to the 220 amino acid was chosen for optimal antigenic expression on E. coli
Summary
Viral encephalopathy and retinopathy cause up to 100% mortalities in juveniles of more than 40 finfish species including those most important to the European marine aquaculture industry such as sea bass (Dicentrarchus labrax) and sea bream (Sparus aurata) [1,2]. All these diseases are caused by viral nervous necrosis viruses (VNNVs) which belong to the Nodaviridae family within the betanodavirus genus [3,4]. Most C proteins of geographically-related betanodaviruses share up to 98–99% of their amino acid sequence
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
