scholarly journals Nervous Necrosis Virus-like Particle (VLP) Vaccine Stimulates European Sea Bass Innate and Adaptive Immune Responses and Induces Long-Term Protection against Disease

Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1477
Author(s):  
Sofie Barsøe ◽  
Kerstin Skovgaard ◽  
Dagoberto Sepúlveda ◽  
Ansgar Stratmann ◽  
Niccolò Vendramin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
Expression Analysis ◽  
Gene Expression Analysis ◽  
Sea Bass ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass ◽  
Post Vaccination ◽  
Virus Like Particle

The rapidly increasing Mediterranean aquaculture production of European sea bass is compromised by outbreaks of viral nervous necrosis, which can be recurrent and detrimental. In this study, we evaluated the duration of protection and immune response in sea bass given a single dose of a virus-like particle (VLP)-based vaccine. Examinations included experimental challenge with nervous necrosis virus (NNV), serological assays for NNV-specific antibody reactivity, and immune gene expression analysis. VLP-vaccinated fish showed high and superior survival in challenge both 3 and 7.5 months (1800 and 4500 dd) post-vaccination (RPS 87 and 88, OR (surviving) = 16.5 and 31.5, respectively, p < 0.01). Although not providing sterile immunity, VLP vaccination seemed to control the viral infection, as indicated by low prevalence of virus in the VLP-vaccinated survivors. High titers of neutralizing and specific antibodies were produced in VLP-vaccinated fish and persisted for at least ~9 months post-vaccination as well as after challenge. However, failure of immune sera to protect recipient fish in a passive immunization trial suggested that other immune mechanisms were important for protection. Accordingly, gene expression analysis revealed that VLP-vaccination induced a mechanistically broad immune response including upregulation of both innate and adaptive humoral and cellular components (mx, isg12, mhc I, mhc II, igm, and igt). No clinical side effects of the VLP vaccination at either tissue or performance levels were observed. The results altogether suggested the VLP-based vaccine to be suitable for clinical testing under farming conditions.

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 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 H-Ras gene takes part to the host immune response to COVID-19

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Salvatore Sciacchitano ◽  
Andrea Sacconi ◽  
Claudia De Vitis ◽  
Giovanni Blandino ◽  
Giulia Piaggio ◽  
...  
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
Expression Analysis ◽  
Gene Expression Analysis ◽  
Severe Disease ◽  
Host Immune Response ◽  
Severe Form ◽  
Ras Gene ◽  
Peripheral Blood Mononuclear ◽  
Ras Genes

AbstractRas gene family members play a relevant role in cancer, especially when they are mutated. However, they may play additional roles in other conditions beside cancer. We performed gene expression analysis using the NanoString PanCancer IO 360 panel in the peripheral blood mononuclear cell (PBMC) of six COVID-19 patients and we found that H-Ras gene was significantly upregulated, while both K-Ras and N-Ras genes were downregulated. In particular, H-Ras gene upregulation was more evident in COVID-19 patients with a more severe disease. We compared our results with those obtained by analyzing two different and independent datasets, including a total of 53 COVID-19 patients, in which the gene expression analysis was performed using the Immunology_V2 panel. Comparative analysis of the H-Ras gene expression in these patients confirmed our preliminary results. In both of them, in fact, we were able to confirm the upregulation of the expression of the H-Ras gene. The exact role of this specific upregulation of the H-Ras gene in response to SARS-CoV-2 infection and its possible role in cancer still remains to be elucidated. In conclusion, H-Ras gene participates to the host immune response to SARS-CoV-2 virus infection, especially in patients affected by the most severe form of the COVID-19.

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.

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