scholarly journals Sea Bass Immunization to Downsize the Betanodavirus Protein Displayed in the Surface of Inactivated Repair-Less Bacteria

Vaccines ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 94
Author(s):  
Lama ◽  
Pereiro ◽  
Novoa ◽  
Coll
Keyword(s):  
Culture Media ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Surface Expression ◽  
Environmental Safety ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass ◽  
Viral Nervous Necrosis ◽  
Casein Hydrolysates

: 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.

scholarly journals Sea Bass Immunization to Downsized Betanodavirus Protein Displayed in The Surface of Dna-Damaged Repair-Less Bacteria

2019 ◽  
Author(s):  
Raquel Lama ◽  
Patricia Pereiro ◽  
Beatriz Novoa ◽  
Julio Coll
Keyword(s):  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Surface Expression ◽  
Environmental Safety ◽  
Small Fish ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass ◽  
C Protein ◽  
Viral Nervous Necrosis

This work describes practical 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 in irreversibly DNA-damaged DNA-repair-less E.coli displaying at their surface a downsized antigen. In this work we, i) maximized bacterial expression levels by downsizing the C protein to a fragment (frgC91-220) containing most of its antigenicity, ii) developed an scalable autoinduction bacterial media based in soy-bean increasing membrane display and reproducibility, iii) enriched surface expression by screening different anchors from several prokaryotic origins (anchor+frgC91-220), 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 spinycterin chassis. These second generation of spinycterins protected fish against VNNV challenge with partial (Nmistic+frgC91-220) or 100 % (YBEL+frgC91-220 ) protection, in contrast to those fish immunized with frgC91-220 spinycterins. The proposed spinycterin platform has high levels of environmental safety and cost effectiveness, thus providing potential for small fish vaccines for sustainable aquaculture.

scholarly journals Different survival of three populations of European sea bass (Dicentrarchus labrax) following challenge with two variants of nervous necrosis virus (NNV)

2021 ◽  
Vol 19 ◽  
pp. 100621
Author(s):  
Sofie Barsøe ◽  
François Allal ◽  
Alain Vergnet ◽  
Marc Vandeputte ◽  
Niels Jørgen Olesen ◽  
...  
Keyword(s):  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass

scholarly journals Long-Term Protection and Serologic Response of European Sea Bass Vaccinated with a Betanodavirus Virus-Like Particle Produced in Pichia pastoris

Vaccines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 447
Author(s):  
Sofie Barsøe ◽  
Anna Toffan ◽  
Francesco Pascoli ◽  
Ansgar Stratmann ◽  
Tobia Pretto ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
High Titer ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Nervous Necrosis Virus ◽  
European Sea Bass ◽  
Post Vaccination ◽  
Serologic Response ◽  
Viral Nervous Necrosis ◽  
Virus Like Particle

Viral Nervous Necrosis (VNN) causes high mortality and reduced growth in farmed European sea bass (Dicentrarchus labrax) in the Mediterranean. In the current studies, we tested a novel Pichia-produced virus-like particle (VLP) vaccine against VNN in European sea bass, caused by the betanodavirus “Red-Spotted Grouper Nervous Necrosis Virus” (RGNNV). European sea bass were immunized with a VLP-based vaccine formulated with different concentrations of antigen and with or without adjuvant. Antibody response was evaluated by ELISA and serum neutralization. The efficacy of these VLP-vaccine formulations was evaluated by an intramuscular challenge with RGNNV at different time points (1, 2 and 10 months post-vaccination) and both dead and surviving fish were sampled to evaluate the level of viable virus in the brain. The VLP-based vaccines induced an effective protective immunity against experimental infection at 2 months post-vaccination, and even to some degree at 10 months post-vaccination. Furthermore, the vaccine formulations triggered a dose-dependent response in neutralizing antibodies. Serologic response and clinical efficacy, measured as relative percent survival (RPS), seem to be correlated with the administered dose, although for the individual fish, a high titer of neutralizing antibodies prior to challenge was not always enough to protect against disease. The efficacy of the VLP vaccine could not be improved by formulation with a water-in-oil (W/O) adjuvant. The developed RGNNV-VLPs show a promising effect as a vaccine candidate, even without adjuvant, to protect sea bass against disease caused by RGNNV. However, detection of virus in vaccinated survivors means that it cannot be ruled out that survivors can transmit the virus.

scholarly journals Capsid amino acids at positions 247 and 270 are involved in the virulence of betanodaviruses to European sea bass

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Patricia Moreno ◽  
Sandra Souto ◽  
Rocio Leiva-Rebollo ◽  
Juan J. Borrego ◽  
Isabel Bandín ◽  
...  
Keyword(s):  
Amino Acids ◽  
Immune Response ◽  
Fish Species ◽  
Sea Bass ◽  
Fish Mortality ◽  
Wild Type Virus ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass

Abstract European sea bass (Dicentrarchus labrax) is severely affected by nervous necrosis disease, caused by nervous necrosis virus (NNV). Two out of the four genotypes of this virus (red-spotted grouper nervous necrosis virus, RGNNV; and striped jack nervous necrosis virus, SJNNV) have been detected in sea bass, although showing different levels of virulence to this fish species. Thus, sea bass is highly susceptible to RGNNV, whereas outbreaks caused by SJNNV have not been reported in this fish species. The role of the capsid protein (Cp) amino acids 247 and 270 in the virulence of a RGNNV isolate to sea bass has been evaluated by the generation of recombinant RGNNV viruses harbouring SJNNV-type amino acids in the above mentioned positions (Mut247Dl965, Mut270Dl965 and Mut247 + 270Dl965). Viral in vitro and in vivo replication, virus virulence and fish immune response triggered by these viruses have been analysed. Mutated viruses replicated on E-11 cells, although showing some differences compared to the wild type virus, suggesting that the mutations can affect the viral cell recognition and entry. In vivo, fish mortality caused by mutated viruses was 75% lower, and viral replication in sea bass brain was altered compared to non-mutated virus. Regarding sea bass immune response, mutated viruses triggered a lower induction of IFN I system and inflammatory response-related genes. Furthermore, mutations caused changes in viral serological properties (especially the mutation in amino acid 270), inducing higher seroconversion and changing antigen recognition.

scholarly journals Induction of a Protective Immune Response against Viral Nervous Necrosis in the European Sea Bass Dicentrarchus labrax by Using Betanodavirus Virus-Like Particles

2006 ◽  
Vol 80 (20) ◽  
pp. 10201-10207 ◽  
Author(s):  
R. Thiéry ◽  
J. Cozien ◽  
J. Cabon ◽  
F. Lamour ◽  
M. Baud ◽  
...  
Keyword(s):  
Immune Response ◽  
Expression System ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Baculovirus Expression System ◽  
Single Type ◽  
European Sea Bass ◽  
Virus Like Particles ◽  
Viral Nervous Necrosis ◽  
Baculovirus Expression

ABSTRACT Betanodaviruses are causative agents of viral nervous necrosis (VNN), a devastating disease of cultured marine fish worldwide. Virus particles contain a single type of coat protein that spontaneously assembles into virus-like particles (VLPs) when expressed in a baculovirus expression system. In the present study, the immunogenicity of betanodavirus VLPs and the protection they confer against VNN in the European sea bass Dicentrarchus labrax were investigated. Enzyme-linked immunosorbent assay and seroneutralization tests performed on plasma from fish vaccinated intramuscularly with doses as low as 0.1 μg of VLPs indicated that the VLPs elicited the synthesis of specific antibetanodavirus antibodies with neutralizing activity. Moreover, fish vaccinated with VLPs were protected from challenge with live virus. Both the immune response and the protective effect against viral challenge were dose dependent. Reverse transcription-PCR data indicated that higher doses of vaccine also reduced the number of fish containing detectable quantities of betanodavirus RNA on day 30 after challenge. Taken together these data strongly support the hypothesis that VLPs obtained in the baculovirus expression system may represent an effective vaccine against VNN.

scholarly journals Resistance to viral nervous necrosis in European sea bass (Dicentrarchus labrax L.): heritability and relationships with body weight, cortisol concentration, and antibody titer

2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Sara Faggion ◽  
Daniela Bertotto ◽  
Massimiliano Babbucci ◽  
Giulia Dalla Rovere ◽  
Rafaella Franch ◽  
...  
Keyword(s):  
Body Weight ◽  
Antibody Titer ◽  
Selective Breeding ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Cortisol Concentration ◽  
European Sea Bass ◽  
Testing Procedures ◽  
Viral Nervous Necrosis ◽  
Highest Posterior Density

Abstract Background Susceptibility of European sea bass (Dicentrarchus labrax L.) to viral nervous necrosis (VNN) is well-known. Interest towards selective breeding as a tool to enhance genetic resistance in this species has increased sharply due to the major threat represented by VNN for farmed sea bass and limitations concerning specific therapeutical measures. A sea bass experimental population (N = 650) was challenged with nervous necrosis virus (NNV) to investigate genetic variation in VNN mortality. In addition, relationships of this trait with serum cortisol concentration after stress exposure, antibody titer against NNV antigens, and body weight at a fixed age were studied to identify potential indicator traits of VNN resistance. Results The estimate of heritability for VNN mortality was moderate and ranged from 0.15 (HPD95%, 95% highest posterior density interval: 0.02, 0.31) to 0.23 (HPD95%: 0.06, 0.47). Heritability estimates for cortisol concentration, antibody titer, and body weight were 0.19 (HPD95%: 0.07, 0.34), 0.36 (HPD95%: 0.16, 0.59) and 0.57 (HPD95%: 0.33, 0.84), respectively. Phenotypic relationships between traits were trivial and not statistically significant, except for the estimated correlation between antibody titer and body weight (0.24). Genetic correlations of mortality with body weight or antibody titer (− 0.39) exhibited a 0.89 probability of being negative. A negligible genetic correlation between mortality and cortisol concentration was detected. Antibody titer was estimated to be positively correlated with body weight (0.49). Conclusions Antibody titer against NNV offers the opportunity to use indirect selection to enhance resistance, while the use of cortisol concentration as an indicator trait in breeding programs for VNN resistance is questionable. The estimate of heritability for VNN mortality indicates the feasibility of selective breeding to enhance resistance to NNV and raises attention to the development of genomic prediction tools to simplify testing procedures for selection candidates.

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