A prepared polysaccharide from the cell wall of yeast, M-Glucan, has previously been demonstrated... more A prepared polysaccharide from the cell wall of yeast, M-Glucan, has previously been demonstrated to have immunostimulatory effects in salmonids as observed by enhanced in vivo non-specific disease resistance in Atlantic salmon, Salmo salar L., and increased in vitro bactericidal activity of rainbow trout, Oncorhynchus mykiss (Walbaum), macrophages. In the present study M-Glucan was injected intraperitoneally into Atlantic salmon and the effect on core components in the non-specific part of the immune system was observed. The hydrogen peroxide (H2O2) production of isolated head kidney macrophages from glucan-injected fish was measured 3 and 6 weeks after M-Glucan treatment and was increased at both time-points upon phorbol myristate acetate-(PMA) triggering. Without PMA triggering the difference was only significant 3 weeks after glucan injection when compared to a control group injected with saline. In a phagocytic assay with macrophages and Vibrio salmonicida the initial uptake of...
Bulletin of The European Association of Fish Pathologists, 2016
TargetFish is a large collaborative project unded by the European Commission under the 7th Frame... more TargetFish is a large collaborative project unded by the European Commission under the 7th Framework Programme or Research and Technological Development (FP7) of the European Union (Grant Agreement 311993). The project that will run or 5 years, started in November 2012 and thus is approximately halway. TargetFish brings together a large number of leading European research groups (RTD) that are experts on esh pathology and immunology and small-to-medium enterprises (SME) as well as some larger industries rom the Biotech and Veterinary sectors, which all share a common interest and experience: vaccination of fish.
Infectious pancreatic necrosis virus (IPNV) is the causative agent of infectious pancreatic necro... more Infectious pancreatic necrosis virus (IPNV) is the causative agent of infectious pancreatic necrosis (IPN) disease in salmonid fish. Recent studies have revealed variation in virulence between isolates of the Sp serotype, associated with certain residues of the structural protein VP2. The isolates are also highly heterogenic in the coding region of the nonstructural VP5 protein. To study the involvement of this protein in the pathogenesis of disease, we generated three recombinant VP5 mutant viruses using reverse genetics. The “wild-type” recombinant NVI15 (rNVI15) virus is virulent, having a premature stop codon at nucleotide position 427, putatively encoding a truncated 12-kDa VP5 protein, whereas rNVI15-15K virus encodes a 15-kDa protein. Recombinant rNVI15-ΔVP5 virus contains a mutation in the initiation codon of the VP5 gene that ablates the expression of VP5. Atlantic salmon postsmolts were challenged to study the virulence characteristics of the recovered viruses in vivo. The...
Adjuvants are helper substances that assist in the development of vaccine efficacy by enhancing t... more Adjuvants are helper substances that assist in the development of vaccine efficacy by enhancing the magnitude, extending the duration and/or directing the nature of the immune response. Most fish vaccines for injection are formulated with oil adjuvants and provide a strong and long-lasting immunity. Inherent problems of such formulations are the injection-site reactions, the challenge being to balance adjuvanticity against reactogenicity to produce a sufficient level of protection with as few side-effects as possible. Current findings on cellular inflammatory responses to oil adjuvanted vaccines in fish and on prediction factors for the effect versus side-effect balance are being discussed. The focus of future vaccine formulation studies will probably comprise the effect of formulation parameters on antigen retention, and the effect of antigen purity and concentration on recipient fish responses at the cellular and cytokine level.
Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), 1992
The pulmonary lesions and multinucleate giant cell formations in porcine dermatosis vegetans were... more The pulmonary lesions and multinucleate giant cell formations in porcine dermatosis vegetans were studied ultrastructurally and cytochemically in seven affected pigs that ranged from one to 120 days of age. At birth, no pulmonary lesions were observed. By seven days of age, there was a moderate infiltration of monocytes/macrophages in the alveoli and interstitium. These changes progressed, and by two weeks of age there was pronounced infiltration of macrophages and lymphocytes in the alveoli. Close apposition of macrophages and lymphocytes was observed, and cellular contact was demonstrated. By three to four weeks of age, small aggregates with epithelioid cells, macrophages, and lymphocytes resembling granulomas were present. In an older pig, aged four months, the inflammatory changes waned. Large macrophages, and large and small multinucleate cells shared common morphological characteristics of cytoplasm endowed with organelles, primary and secondary lysosomes, Golgi profiles, and ...
Individual testing and subsequent removal of eggs from infectious pancreatic necrosis virus (IPNV... more Individual testing and subsequent removal of eggs from infectious pancreatic necrosis virus (IPNV)-positive parents is required for export of salmonid eggs to some farming countries. Testing by cell culture requires more than three weeks before the eggs can be released from quarantine and incurs significant logistic problems and costs. The feasibility of the RT-PCR testing method as offered by several laboratories was therefore evaluated during the current inter-laboratory comparison study. Frozen kidney sub-samples from 100 motherfish of Atlantic salmon (Salmo salar L.) were shipped to three diagnostic laboratories (A, B and C) for testing by RT-PCR and cell culture. Of the 100 examined samples, all proved IPNV-negative by cell culture. Thirty samples were positive by RT-PCR analyses, but only four of these samples were RT-PCR positive in two laboratories and none in any of the three laboratories. From a disease management point of view, the RT-PCR test outcomes gave no reasonable ...
During the last few years, the use of vaccines for disease prevention in aquaculture has expanded... more During the last few years, the use of vaccines for disease prevention in aquaculture has expanded both with regard to the number of fish species and number of microbial diseases. According to the responses to a questionnaire received from 41 countries, vaccination is used in the commercial aquaculture of species like Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), sea bass (Dicentrarchus labrax), sea bream (Sparus aurata), barramundi (Lates calcarifer), tilapia (Tilapia spp), turbot (Scophthalmus maximus L.), yellowtail (Seriola quinqueradiata), purplish and gold-striped amberjack (Seriola dumereli), striped jack (Pseudocaranx dentex) and channel catfish (Ictalurus punctatus). The range of bacterial infections for which vaccines are commercially available now comprises classical vibriosis (Listonella anguillarum, Vibrio ordalii), furunculosis (Aeromonas salmonicida subsp. salmonicida), cold-water vibriosis (Vibrio salmonicida), yersiniosis (Yersinia ruckeri), pas...
Various attempts to develop a vaccine against infectious pancreatic necrosis virus (IPNV) have no... more Various attempts to develop a vaccine against infectious pancreatic necrosis virus (IPNV) have not yielded consistent results. Thus, at present, no commercial vaccine is available that can be used with confidence to immunize fry of salmon and trout. We generated a cDNA clone of the large genome segment A of an IPNV Sp strain and expressed all structural protein genes in insect cells and larvae using a baculovirus expression system. Green fluorescent protein was also coexpressed as a reporter molecule. High yields of IPNV proteins were obtained and the structural proteins self assembled to form virus-like particles (VLPs). We tested the immunogenicity of the putative VLP antigen in immersion vaccine experiments (two concentrations) in rainbow trout (Oncorhynchus mykiss) fry, and by intraperitoneal immunisation of Atlantic salmon (Salmo salar) pre-smolts using an oil adjuvant formulation. Rainbow trout were challenged by immersion using either the Sp or the VR-299 strain of IPNV two o...
The uptake and handling of Vibrio salmonicida in phagocytes of the head kidney of Atlantic salmon... more The uptake and handling of Vibrio salmonicida in phagocytes of the head kidney of Atlantic salmon (Salmo salar L.) were evaluated by light and electron microscopy, including in situ identification of the bacterium by immunolabeling at the light microscopical and the ultrastructural level. Fish were injected with live bacteria, and 4, 24, 48, and 72 hours after inoculation, samples were collected after perfusion fixation. Morphologically, the most prominent change in the course of the experiment was an increasing number of intrasinusoidal, endothelial cell-adherent phagocytes and the elevated number of interstitial melanomacrophages. Immunohistochemically, bacterial antigens were initially identified in intrasinusoidal phagocytes, and at 24 hours postinfection in endothelium-adherent phagocytes and intrasinusoidal melanomacrophages. Later, (48 and 72 hours postinfection), the interstitial melanomacrophages were also found to harbor bacterial antigen. Ultrastructurally, bacteria were ...
Various strains of Atlantic salmon exhibit different levels of susceptibility to infections with ... more Various strains of Atlantic salmon exhibit different levels of susceptibility to infections with the ectoparasitic monogenean Gyrodactylus salaris. The basic mechanisms involved in this differential ability to respond to this monogenean were elucidated using controlled and duplicated challenge experiments. Highly susceptible East Atlantic salmon allowed parasite populations to reach up to 3000 parasites per host within 6 weeks, whereas less susceptible Baltic salmon never reached larger parasite burdens than 122 parasites per host during the same period. The present study, comprising immunohistochemistry and gene expression analyses, showed that highly susceptible salmon erected a response mainly associated with an increased expression of interleukin-1β (IL-1β), interferon-γ (IFN-γ), IL-10 and infiltration of CD3-positive cells in the epidermis of infected fins. Less susceptible salmon showed no initial response in fins but 3–6 weeks post-infection a number of other genes (encoding ...
A prepared polysaccharide from the cell wall of yeast, M-Glucan, has previously been demonstrated... more A prepared polysaccharide from the cell wall of yeast, M-Glucan, has previously been demonstrated to have immunostimulatory effects in salmonids as observed by enhanced in vivo non-specific disease resistance in Atlantic salmon, Salmo salar L., and increased in vitro bactericidal activity of rainbow trout, Oncorhynchus mykiss (Walbaum), macrophages. In the present study M-Glucan was injected intraperitoneally into Atlantic salmon and the effect on core components in the non-specific part of the immune system was observed. The hydrogen peroxide (H2O2) production of isolated head kidney macrophages from glucan-injected fish was measured 3 and 6 weeks after M-Glucan treatment and was increased at both time-points upon phorbol myristate acetate-(PMA) triggering. Without PMA triggering the difference was only significant 3 weeks after glucan injection when compared to a control group injected with saline. In a phagocytic assay with macrophages and Vibrio salmonicida the initial uptake of...
Bulletin of The European Association of Fish Pathologists, 2016
TargetFish is a large collaborative project unded by the European Commission under the 7th Frame... more TargetFish is a large collaborative project unded by the European Commission under the 7th Framework Programme or Research and Technological Development (FP7) of the European Union (Grant Agreement 311993). The project that will run or 5 years, started in November 2012 and thus is approximately halway. TargetFish brings together a large number of leading European research groups (RTD) that are experts on esh pathology and immunology and small-to-medium enterprises (SME) as well as some larger industries rom the Biotech and Veterinary sectors, which all share a common interest and experience: vaccination of fish.
Infectious pancreatic necrosis virus (IPNV) is the causative agent of infectious pancreatic necro... more Infectious pancreatic necrosis virus (IPNV) is the causative agent of infectious pancreatic necrosis (IPN) disease in salmonid fish. Recent studies have revealed variation in virulence between isolates of the Sp serotype, associated with certain residues of the structural protein VP2. The isolates are also highly heterogenic in the coding region of the nonstructural VP5 protein. To study the involvement of this protein in the pathogenesis of disease, we generated three recombinant VP5 mutant viruses using reverse genetics. The “wild-type” recombinant NVI15 (rNVI15) virus is virulent, having a premature stop codon at nucleotide position 427, putatively encoding a truncated 12-kDa VP5 protein, whereas rNVI15-15K virus encodes a 15-kDa protein. Recombinant rNVI15-ΔVP5 virus contains a mutation in the initiation codon of the VP5 gene that ablates the expression of VP5. Atlantic salmon postsmolts were challenged to study the virulence characteristics of the recovered viruses in vivo. The...
Adjuvants are helper substances that assist in the development of vaccine efficacy by enhancing t... more Adjuvants are helper substances that assist in the development of vaccine efficacy by enhancing the magnitude, extending the duration and/or directing the nature of the immune response. Most fish vaccines for injection are formulated with oil adjuvants and provide a strong and long-lasting immunity. Inherent problems of such formulations are the injection-site reactions, the challenge being to balance adjuvanticity against reactogenicity to produce a sufficient level of protection with as few side-effects as possible. Current findings on cellular inflammatory responses to oil adjuvanted vaccines in fish and on prediction factors for the effect versus side-effect balance are being discussed. The focus of future vaccine formulation studies will probably comprise the effect of formulation parameters on antigen retention, and the effect of antigen purity and concentration on recipient fish responses at the cellular and cytokine level.
Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), 1992
The pulmonary lesions and multinucleate giant cell formations in porcine dermatosis vegetans were... more The pulmonary lesions and multinucleate giant cell formations in porcine dermatosis vegetans were studied ultrastructurally and cytochemically in seven affected pigs that ranged from one to 120 days of age. At birth, no pulmonary lesions were observed. By seven days of age, there was a moderate infiltration of monocytes/macrophages in the alveoli and interstitium. These changes progressed, and by two weeks of age there was pronounced infiltration of macrophages and lymphocytes in the alveoli. Close apposition of macrophages and lymphocytes was observed, and cellular contact was demonstrated. By three to four weeks of age, small aggregates with epithelioid cells, macrophages, and lymphocytes resembling granulomas were present. In an older pig, aged four months, the inflammatory changes waned. Large macrophages, and large and small multinucleate cells shared common morphological characteristics of cytoplasm endowed with organelles, primary and secondary lysosomes, Golgi profiles, and ...
Individual testing and subsequent removal of eggs from infectious pancreatic necrosis virus (IPNV... more Individual testing and subsequent removal of eggs from infectious pancreatic necrosis virus (IPNV)-positive parents is required for export of salmonid eggs to some farming countries. Testing by cell culture requires more than three weeks before the eggs can be released from quarantine and incurs significant logistic problems and costs. The feasibility of the RT-PCR testing method as offered by several laboratories was therefore evaluated during the current inter-laboratory comparison study. Frozen kidney sub-samples from 100 motherfish of Atlantic salmon (Salmo salar L.) were shipped to three diagnostic laboratories (A, B and C) for testing by RT-PCR and cell culture. Of the 100 examined samples, all proved IPNV-negative by cell culture. Thirty samples were positive by RT-PCR analyses, but only four of these samples were RT-PCR positive in two laboratories and none in any of the three laboratories. From a disease management point of view, the RT-PCR test outcomes gave no reasonable ...
During the last few years, the use of vaccines for disease prevention in aquaculture has expanded... more During the last few years, the use of vaccines for disease prevention in aquaculture has expanded both with regard to the number of fish species and number of microbial diseases. According to the responses to a questionnaire received from 41 countries, vaccination is used in the commercial aquaculture of species like Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), sea bass (Dicentrarchus labrax), sea bream (Sparus aurata), barramundi (Lates calcarifer), tilapia (Tilapia spp), turbot (Scophthalmus maximus L.), yellowtail (Seriola quinqueradiata), purplish and gold-striped amberjack (Seriola dumereli), striped jack (Pseudocaranx dentex) and channel catfish (Ictalurus punctatus). The range of bacterial infections for which vaccines are commercially available now comprises classical vibriosis (Listonella anguillarum, Vibrio ordalii), furunculosis (Aeromonas salmonicida subsp. salmonicida), cold-water vibriosis (Vibrio salmonicida), yersiniosis (Yersinia ruckeri), pas...
Various attempts to develop a vaccine against infectious pancreatic necrosis virus (IPNV) have no... more Various attempts to develop a vaccine against infectious pancreatic necrosis virus (IPNV) have not yielded consistent results. Thus, at present, no commercial vaccine is available that can be used with confidence to immunize fry of salmon and trout. We generated a cDNA clone of the large genome segment A of an IPNV Sp strain and expressed all structural protein genes in insect cells and larvae using a baculovirus expression system. Green fluorescent protein was also coexpressed as a reporter molecule. High yields of IPNV proteins were obtained and the structural proteins self assembled to form virus-like particles (VLPs). We tested the immunogenicity of the putative VLP antigen in immersion vaccine experiments (two concentrations) in rainbow trout (Oncorhynchus mykiss) fry, and by intraperitoneal immunisation of Atlantic salmon (Salmo salar) pre-smolts using an oil adjuvant formulation. Rainbow trout were challenged by immersion using either the Sp or the VR-299 strain of IPNV two o...
The uptake and handling of Vibrio salmonicida in phagocytes of the head kidney of Atlantic salmon... more The uptake and handling of Vibrio salmonicida in phagocytes of the head kidney of Atlantic salmon (Salmo salar L.) were evaluated by light and electron microscopy, including in situ identification of the bacterium by immunolabeling at the light microscopical and the ultrastructural level. Fish were injected with live bacteria, and 4, 24, 48, and 72 hours after inoculation, samples were collected after perfusion fixation. Morphologically, the most prominent change in the course of the experiment was an increasing number of intrasinusoidal, endothelial cell-adherent phagocytes and the elevated number of interstitial melanomacrophages. Immunohistochemically, bacterial antigens were initially identified in intrasinusoidal phagocytes, and at 24 hours postinfection in endothelium-adherent phagocytes and intrasinusoidal melanomacrophages. Later, (48 and 72 hours postinfection), the interstitial melanomacrophages were also found to harbor bacterial antigen. Ultrastructurally, bacteria were ...
Various strains of Atlantic salmon exhibit different levels of susceptibility to infections with ... more Various strains of Atlantic salmon exhibit different levels of susceptibility to infections with the ectoparasitic monogenean Gyrodactylus salaris. The basic mechanisms involved in this differential ability to respond to this monogenean were elucidated using controlled and duplicated challenge experiments. Highly susceptible East Atlantic salmon allowed parasite populations to reach up to 3000 parasites per host within 6 weeks, whereas less susceptible Baltic salmon never reached larger parasite burdens than 122 parasites per host during the same period. The present study, comprising immunohistochemistry and gene expression analyses, showed that highly susceptible salmon erected a response mainly associated with an increased expression of interleukin-1β (IL-1β), interferon-γ (IFN-γ), IL-10 and infiltration of CD3-positive cells in the epidermis of infected fins. Less susceptible salmon showed no initial response in fins but 3–6 weeks post-infection a number of other genes (encoding ...
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