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Oslo, Norway

Infectious pancreatic necrosis virus (IPNV) is a member of the family Birnaviridae that has been linked to high mortalities in juvenile salmonids and postsmolt stages of Atlantic salmon (Salmo salar L.) after transfer to seawater. IPN vaccines have been available for a long time but their efficacy has been variable. The reason for the varying immune response to these vaccines has not well defined and studies on the importance of using vaccine trains homologous to the virulent field strain has not been conclusive. In this study we prepared one vaccine identical to the virulent Norwegian Sp strain NVI-015 (NCBI: 379740) (T217A221T247 of VP2) and three other vaccine strains developed using the same genomic backbone altered by reverse genetics at three residues yielding variants, T217T221T247, P217A221A247, P217T221A247. These 4 strains, differing in these three positions only, were used as inactivated, oil-adjuvanted vaccines while two strains, T217A221T247 and P217T221A247, were used as live vaccines. The results show that these three residues of the VP2 capsid play a key role for immunogenicity of IPNV vaccines. The virulent strain for inactivated vaccines elicited the highest level of virus neutralization (VN) titers and ELISA antibodies. Interestingly, differences in immunogenicity were not reflected in differences in post challenge survival percentages (PCSP) for oil-adjuvanted, inactivated vaccines but clearly so for live vaccines (TAT and PTA). Further post challenge viral carrier state correlated inversely with VN titers at challenge for inactivated vaccines and prevalence of pathology in target organs inversely correlated with protection for live vaccines. Overall, our findings show that a few residues localized on the VP2-capsid are important for immunogenicity of IPNV vaccines. © 2013 Munang'andu et al. Source

Holvold L.B.,University of Tromso | Fredriksen B.N.,PHARMAQ AS | Bogwald J.,University of Tromso | Dalmo R.A.,University of Tromso
Fish and Shellfish Immunology

The use of poly-(. D,. L-lactic-. co-glycolic) acid (PLGA) particles as carriers for DNA delivery has received considerable attention in mammalian studies. DNA vaccination of fish has been shown to elicit durable transgene expression, but no reports exist on intramuscular administration of PLGA-encapsulated plasmid DNA (pDNA). We injected Atlantic salmon. (Salmo salar L.) intramuscularly with a plasmid vector containing a luciferase. (Photinus pyralis) reporter gene as a) naked pDNA, b) encapsulated into PLGA nano- (~320nm) (NP) or microparticles (~4μm) (MP), c) in an oil-based formulation, or with empty particles of both sizes. The ability of the different pDNA-treatments to induce transgene expression was analyzed through a 70-day experimental period. Anatomical distribution patterns and depot effects were determined by tracking isotope labeled pDNA. Muscle, head kidney and spleen from all treatment groups were analyzed for proinflammatory cytokines (TNF-α, IL-1β), antiviral genes (IFN-α, Mx) and cytotoxic T-cell markers (CD8, Eomes) at mRNA transcription levels at days 1, 2, 4 and 7. Histopathological examinations were performed on injection site samples from days 2, 7 and 30. Injection of either naked pDNA or the oil-formulation was superior to particle treatments for inducing transgene expression at early time-points. Empty particles of both sizes were able to induce proinflammatory immune responses as well as degenerative and inflammatory pathology at the injection site. Microparticles demonstrated injection site depots and an inflammatory pathology comparable to the oil-based formulation. In comparison, the distribution of NP-encapsulated pDNA resembled that of naked pDNA, although encapsulation into NPs significantly elevated the expression of antiviral genes in all tissues. Together the results indicate that while naked pDNA is most efficient for inducing transgene expression, the encapsulation of pDNA into NPs up-regulates antiviral responses that could be of benefit to DNA vaccination. © 2013 Elsevier Ltd. Source

Kawano F.,Nippon Suisan Kaisha Ltd. | Hirazawa N.,Nippon Suisan Kaisha Ltd. | Gravningen K.,PHARMAQ Ltd. | Berntsen J.O.,PHARMAQ AS

We investigated the effects of dietary Rometr{script}30 (sulfadimethoxine-ormetoprim (SDMX-OMP)) on Cryptocaryon irritans infection in red sea bream Pagrus major and tiger puffer Takifugu rubripes. In Experiment I, 100% mortality of P. major due to C. irritans infection was observed at 10. days and 21. days after exposure to theronts (infective stage) in the a control group without Rometr{script}30 and the group treated with 50. mg Rometr{script}30/kg body weight (BW)/day for 14. days, respectively. Thus, mortality in the treated group was markedly delayed compared with that in the control group. In Experiment II, 100% mortality of P. major in the control group due to C. irritans infection was recorded at 11. days after exposure to theronts. In contrast, mortality due to parasite infection was not observed in the group treated with Rometr{script}30 at 50. mg/kg BW/day for 14. days, and no parasites were found in any surviving fish after 33. days exposure. In addition, the number of parasites on the gills of T. rubripes treated with 50. mg Rometr{script}30/kg BW/day for 14. days was significantly lower than that in the control group after 16. days exposure. These results show that in-feed Rometr{script}30 at 50. mg/kg BW/day for 14. days had antiparasitic and therapeutic effects against C. irritans in both P. major and T. rubripes. Thus, dietary Rometr{script}30 could be useful for controlling C. irritans infection. © 2012 Elsevier B.V.. Source

Drangsholt T.M.K.,Norwegian University of Life Sciences | Gjerde B.,Norwegian University of Life Sciences | Odegard J.,Norwegian University of Life Sciences | Finne-Fridell F.,PHARMAQ AS | Bentsen H.B.,Nofima Marin

Furunculosis (Aeromonoas salmonicida) is an important disease in Atlantic salmon (Salmo salar) farming. Vaccination and selective breeding for increased resistance to the disease on the basis of challenge tests of unvaccinated fish are used as complementary prophylactic methods. An important issue is whether genetic predisposition to infection is consistent across vaccinated and unvaccinated fish. Hence, the main objective of this study was to determine the magnitude of the genetic associations (correlations) between resistance to furunculosis in vaccinated and unvaccinated fish, and to estimate the magnitude of the correlation of resistance to furunculosis with resistance to the viral diseases infectious pancreatic necrosis (IPN) and infectious salmon anaemia (ISA). Sub-samples of unvaccinated and vaccinated salmon from 150 full-sib families were subjected to separate cohabitation challenge tests. Substantial genetic variation was found in resistance to furunculosis in both the unvaccinated (heritabilities of 0.510.05) and vaccinated (0.390.06) fish. However, the genetic correlation between resistance to furunculosis in the two groups was low (0.320.13), indicating a weak genetic association between resistance in the two groups. Hence, the current selection strategy on the basis of challenge tests of unvaccinated fish is likely to produce low genetic improvement in resistance to furunculosis under field conditions, where fish are vaccinated with an effective vaccine. Evidence was found of significantly favourable genetic associations of resistance to furunculosis in unvaccinated (but less so for vaccinated) fish with resistance to both IPN and ISA (unvaccinated fish), indicating that vaccination mask genetic associations between resistance to different diseases. © 2011 Macmillan Publishers Limited All rights reserved. Source

Karlsen M.,PHARMAQ AS | Tingbo T.,PHARMAQ AS | Solbakk I.-T.,PHARMAQ AS | Furevik A.,PHARMAQ AS | Aas-Eng A.,PHARMAQ AS

Pancreas disease (PD) in salmonid fish is caused by an infection with Salmonid alphavirus (SAV) and remains as one of the major health problems in the European fish farming industry. Sequence studies have revealed a genetic diversity among viral strains. A subtype of SAV (SAV3) is causing an epizootic in farmed salmonids in Norway. Here we evaluate efficacy and safety of an inactivated virus vaccine based on ALV405, a strain of SAV3 that was isolated from Norwegian salmon. The vaccine provided an average relative percent survival (RPS) of 98.5 in an intraperitoneal challenge model, and induced nearly total protection against PD in a cohabitant challenge model. It provided significant protection against SAV-induced mortality also in a field trial under industrial conditions. Local reactions seen as melanization and adhesions in the visceral cavity were less severe than those induced by two commercial vaccines. Finally, we demonstrated that the protection is not impaired when the ALV405 antigen is combined with other viral or bacterial antigens in a polyvalent vaccine. The results confirm that efficient and safe protection against SAV infection and development of PD is possible using an inactivated virus vaccine, both alone and as a component in a polyvalent vaccine. © 2012 Elsevier Ltd. Source

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