Jarl Bøgwald | UiT The Arctic University of Norway (original) (raw)

Papers by Jarl Bøgwald

Journal of Fish Diseases, Mar 24, 2013

Gene expression profiling has opened new directions of investigative immunobiology (Appay et al. ... more Gene expression profiling has opened new directions of investigative immunobiology (Appay et al. 2007). T-cell-derived cytokines are major determinants of the outcome of immune responses (Sakkas et al. 1998). The existence of the basic effector Thl, Th2, Treg and Th17 subsets is now well accepted in mammalian immunology and is being exploited to plan therapeutic and vaccination strategies. However, we do not yet know the full extent of T-cell diversity and the nature of the initial signals that determines the T-cell response pattern in teleosts. Thus, to understand the basis of protective immunity and the molecular mechanisms involved in activation of T-cell-mediated immune response (at the transcript level) during immunization of fish using oil-based vaccines, we investigated gene transcription profile of cytokines indicative of the presence of the different T-cell subsets Th1/Th2/ Treg/Th17, transcription factors for Th1/Th2 and specific T-cell marker CD8a, prior to and following vaccination with oil-adjuvanted A. salmonicida subspecies salmonicida or infectious pancreatic necrosis virus (IPNV) in Atlantic salmon. Oiladjuvanted vaccines have shown to be effective against furunculosis (Midtlyng 1997) and IPNV (Hill & Dixon 1977) in challenge trials. Atlantic salmon, Salmo salar L. (80–100 g), were kept at the Aquaculture Research Station (Tromsø, Norway) in circular 500L tanks supplied with recirculating fresh water at an ambient temperature of approximately 10 °C with 12/12 h illumination and fed a commercial pellet diet. Eighty fish were placed in each tank per group, and the fish were acclimatized for 2 weeks prior to vaccination. Prior to vaccination, fish were anaesthetized in 0.005% benzocaine. Fish were killed using 0.01% benzocaine prior to collection of different tissues. The experiment was approved by ‘FDU’ (http://www. mattilsynet.no/fdu/) to be in accordance with the animal welfare act as required by Norwegian law. Vaccination was done i.p, with 0.1 mL of preparation fish . The different vaccine preparations used in this study are shown in Table 1. All experimental preparations were supplied by PHARMAQ AS. The oil-adjuvanted inactivated preparations were formulated as water-in-oil emulsions (W/O), where the water phase with the antigens was dispersed into an oil phase. Group A served as negative control (without adjuvant and antigen) and group B as adjuvant control (without antigen). Spleen and head kidney tissues were sampled aseptically from fish of all groups at 1, 2, 5, 7, 14 and 28 days postvaccination (dpv), immediately transferred to RNAlater (Ambion) and stored at 20 °C. Total RNA extraction and real-time PCR were conducted as previously described (Kumari, Bogwald & Dalmo 2009). For each mRNA, gene expression was normalized to the elongation factor 1a (EF1a) mRNA content using the Pfaffl method (Pfaffl 2001). The primers used are shown in Table 2. The log-transformed data were analysed by ANOVA and a Tukey’s multiple range test to determine the differences between groups using SYSTAT 13. For testing of significance of correlation between the Correspondence J Kumari and R A Dalmo, Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, N-9037 Tromsø, Norway (e-mails: jaya.kumari@uit.no and roy.dalmo@uit.no)

Biology

The overexpression of GATA-3, T-bet and TGF-ß may theoretically induce IL-4/A, IFN-γ and IL-17A e... more The overexpression of GATA-3, T-bet and TGF-ß may theoretically induce IL-4/A, IFN-γ and IL-17A expression, respectively. Whether this also applies to fish is not yet known. The plasmid vectors encoding reporter gene (RFP)-tagged T-bet, GATA-3 and TGF-ß were used as overexpression tools, transfected into cells or injected intramuscularly to monitor the expression of IFN-γ, IL-4/13A and IL-17A. In addition, the fish were either experimentally challenged with Vibrio anguillarum (VA group) or Piscirickettsia salmonis (PS group). The reporter gene (RFP) inserted upstream of the GATA-3, T-bet and TGF-ß genes, was observed in muscle cell nuclei and in inflammatory cells after intramuscular (i.m.) injection. PS group: following the injection of GATA-3 and T-bet-encoding plasmids, the expression of GATA-3 and T-bet was high at the injection site. The spleen expression of IFN-γ, following the injection of a T-bet-encoding plasmid, was significantly higher on day 2. VA group: The T-bet and GA...

Principles of Fish Immunology, 2022

Research on the innate immunity has accelerated over the last decades. The main reason for this h... more Research on the innate immunity has accelerated over the last decades. The main reason for this has been the discovery of receptors recognizing danger molecules from pathogens. This has been facilitated through genome and transcriptome sequencing of different fish species. Also, endogenous host molecules from sterile physiological insults may also bind to certain receptors and induce immunological processes. The magnitude and quality of adaptive immunity are known to be dependent on the instructions the innate response gives. This chapter gives an overview of selected innate immune organs/tissues, factors, and processes that have been suggested to possess important roles during innate immune response in fish.

Journal of Fish Diseases, 2021

The vertebrates (Figure 1) are a subphylum of the chordata, characterized by the possession of a ... more The vertebrates (Figure 1) are a subphylum of the chordata, characterized by the possession of a brain enclosed in a skull, ears, kidney and other organs. In most vertebrates, a well-formed bony or cartilaginous vertebral column or backbone is enclosing the spinal cord (Lawrence, 1997). Fish constitute more than one-half of the total number of approximately 48,000 recognized vertebrate species living today. The teleosts (modern bony fishes) represent the majority. The remainders are elasmobranch (sharks and rays, approximately 700 species) and about 170 other species (Nelson, 1994). Studies in fish, amphibians and reptiles have recently revealed that even these vertebrates carry a specialized endothelium that carry out a scavenger function corresponding to that of the rat liver endothelial cells (Seternes et al., 2002). An overview over the anatomical distribution of soluble markers and the presence of scavenger endothelial cells in different fish is presented in Table 1.

International Journal of Molecular Sciences, 2021

Immersion and intraperitoneal injection are the two most common methods used for the vaccination ... more Immersion and intraperitoneal injection are the two most common methods used for the vaccination of fish. Because both methods require that fish are handled and thereby stressed, oral administration of vaccines as feed supplements is desirable. In addition, in terms of revaccination (boosting) of adult fish held in net pens, oral administration of vaccines is probably the only feasible method to obtain proper protection against diseases over long periods of time. Oral vaccination is considered a suitable method for mass immunization of large and stress-sensitive fish populations. Moreover, oral vaccines may preferably induce mucosal immunity, which is especially important to fish. Experimental oral vaccine formulations include both non-encapsulated and encapsulated antigens, viruses and bacteria. To develop an effective oral vaccine, the desired antigens must be protected against the harsh environments in the stomach and gut so they can remain intact when they reach the lower gut/in...

Microorganisms, 2019

Immersion vaccines are used for a variety of aquacultured fish to protect against infectious dise... more Immersion vaccines are used for a variety of aquacultured fish to protect against infectious diseases caused by bacteria and viruses. During immersion vaccination the antigens are taken up by the skin, gills or gut and processed by the immune system, where the resulting response may lead to protection. The lack of classical secondary responses following repeated immersion vaccination may partly be explained by the limited uptake of antigens by immersion compared to injection. Administration of vaccines depends on the size of the fish. In most cases, immersion vaccination is inferior to injection vaccination with regard to achieved protection. However, injection is problematic in small fish, and fry as small as 0.5 gram may be immersion vaccinated when they are considered adaptively immunocompetent. Inactivated vaccines are, in many cases, weakly immunogenic, resulting in low protection after immersion vaccination. Therefore, during recent years, several studies have focused on diffe...

Fish Vaccines, 2016

Vaccination is the most appropriate method to control infectious diseases that threaten the aquac... more Vaccination is the most appropriate method to control infectious diseases that threaten the aquaculture industry worldwide. Unfortunately, vaccines are usually not able to confer protection on their own, especially those vaccines based on recombinant antigens or inactivated pathogens. Therefore, the use of adjuvants or immunostimulants is often necessary to increase vaccine efficacy. Furthermore, an important additional problem that limits the entry of novel fish vaccines to the market is that many of the vaccines experimentally produced only work when injected (either intraperitoneally or intramuscularly). Therefore, the search for alternative methods of mass vaccine delivery (oral or immersion) should also be addressed in parallel. Unfortunately, it is probable that the search for a specific combination of antigen/adjuvant/delivery method has to be experimentally addressed for each pathogen/fish species, and only a few general conclusions can be drawn from each of these studies. In this chapter, we summarise previous studies performed with both traditional and new generation adjuvants as well as those studies that have explored methods for vaccine delivery alternative to injection.

Developmental and comparative immunology, Jan 4, 2015

The RAR-related orphan receptors (RORs) are members of the nuclear receptor family of intracellul... more The RAR-related orphan receptors (RORs) are members of the nuclear receptor family of intracellular transcription factors. In this study, we examined the regulatory properties of RORα (CsRORα) and RORγ (CsRORγ) in tongue sole (Cynoglossus semilaevis). CsRORα and CsRORγ expression was detected in major lymphoid organs and altered to significant extents after bacterial and viral infection. CsRORα enhanced the activities of CsIL-17C, CsIL-17D, and CsIL-17F promoters, which contain CsRORα and CsRORγ binding sites. CsRORγ also upregulated the promoter activities of CsIL-17D and CsIL-17F but not CsIL-17C. CsRORα and CsRORγ proteins were detected in the nucleus, and overexpression of CsRORα in tongue sole significantly increased the expression of CsIL-17C, CsIL-17D, and CsIL-17F, whereas overexpression of CsRORγ significantly increased the expression of CsIL-17C and CsIL-17F but no CsIL-17D. These results indicate that RORα and RORγ in teleost regulate the expression of IL-17 members in di...

Infectious Disease in Aquaculture, 2012

Abstract: Use of injection vaccines plays a key role in controlling infectious diseases in the aq... more Abstract: Use of injection vaccines plays a key role in controlling infectious diseases in the aquaculture industry. Since 1990 oil-adjuvanted vaccines have been the most widespread and most efficacious vaccines available. However, side effects such as retardation in growth, pigmentation and adherence of intestines have initiated a search for new adjuvants, even though considerable advances with respect to adverse side effects have been achieved during the latest years. Experimental vaccines have included immunostimulants such as beta-glucans, polyinosinic polycytidylic acid (poly I:C), CpG, flagellin, and cytokines free or encapsulated in polymers/particles. Encapsulation of vaccines in biodegradable poly(lactic-co-glycolic acid (PLGA) is especially intriguing.

Fish & Shellfish Immunology, 1996

The uptake and distribution ofAeromonas salmonicidalipopolysaccharide (LPS) in Atlantic salmon,Sa... more The uptake and distribution ofAeromonas salmonicidalipopolysaccharide (LPS) in Atlantic salmon,Salmo salarL., was investigated. The purified LPS molecule was radiolabelled by bromine oxidation and subsequent sodium borotritide reduction, or fluorescein labelled. After intravenous injection, high amounts of radiolabelled LPS was found in the spleen, liver, anterior and posterior kidneys at 30 min and 2h. Twenty four hours after i.v. administration, the spleen still contained high amounts of radioactivity, the liver contained increased amounts while the anterior and posterior kidneys showed reduced contents of radioactivity compared with the findings 30 min and 2h after administration. After peroral administration, relatively less radioactive LPS accumulated in the liver compared with the spleen and kidneys at 0·5, 1, 4 and 24h. At 24 and 48h after administration the anterior intestine contained high amounts of radioactivity while the posterior intestine contained low amounts. Histological examinations of tissue sections revealed accumulation of fluorescein-labelled LPS in kidney sinusoidal endothelial cells and macrophages and in splenic ellipsoid sheath cells (macrophages and reticular cells). Liver endothelial cells also showed accumulation of FITC-LPS.

Fish & Shellfish Immunology, 2000

Radiolabelled bacterial lipopolysaccharide (3 H-LPS) obtained from Aeromonas salmonicida subsp. s... more Radiolabelled bacterial lipopolysaccharide (3 H-LPS) obtained from Aeromonas salmonicida subsp. salmonicida was added to the petri dishes containing yolk sac larvae of Atlantic halibut (Hippoglossus hippoglossus L.). The larvae were exposed either to 6•25, 12•5, 25, 50 or 100 g 3 H-LPS ml 1. The uptake was both dependent on the LPS concentration and the time of exposure. After 5 days of exposure, each larva contained 1•8-7•4 ng 3 H-LPS dependent on the initial concentration. After 10 days of exposure each larva contained 7•0-12•4 ng LPS and after 15 days they contained 18•3-34•9 ng 3 H-LPS. Fluorescence microscopic analysis of sections obtained from larvae exposed to FITC-LPS (25, 50 and 100 g ml 1) for 5, 10 and 15 days, revealed fluorescence in intestinal epithelial cells, cells in the connective tissue adjacent to the intestine, in cells located between the integumental layer and yolk sac, and in some epithelial cells in the integument. By use of immunohistochemical techniques, LPS was confined to intestinal epithelial cells, lumen of excretory duct and in numerous cells in the epidermal layer. Control specimens did not contain fluorescence or were immunohistochemically negative for LPS. In groups of larvae exposed to 12•5, 25, 50 and 100 g LPS ml 1 , the survival was significantly increased after exposure to 50 and 100 g LPS ml 1 from day 20 (96 d) and throughout the yolk sac period compared to untreated larvae.

Fish & Shellfish Immunology, 2011

Foxp3 is a T cell-specific transcription factor and plays a key role in the development of Treg c... more Foxp3 is a T cell-specific transcription factor and plays a key role in the development of Treg cells and in the immune regulatory process during inflammation. Here we report cloning and characterization of the full-length cDNA of Atlantic salmon Foxp3, which possesses a Forkhead domain, a zinc finger domain and a leucine-zipper domain as its counterpart in mammals. Foxp3 is highly expressed in thymus. Furthermore, regulated expression was observed in head kidney cells in response to β-glucan and mitogens (LPS and ConA), and in the head kidney, spleen and liver after intraperitoneal injection of live Aeromonas salmonicida. In addition, transfection of CHSE-214 cells with salmon Foxp3 fused with a C-termial RFP tag, resulted in the expression of the transgene in and close to the nuclei upon stimulation. Taken together, these results suggest the presence of a Foxp3 gene in Atlantic salmon that may be an important transcription factor in immune regulation, and further research may reveal the existence of Treg-like T cells in this species.

Journal of Leukocyte Biology, 1984

Mouse peritoneal macrophages stimulated with insoluble glycans in vitro release high amounts of a... more Mouse peritoneal macrophages stimulated with insoluble glycans in vitro release high amounts of acid hydrolases, N-acetyl-β-D-glucosaminidase, β-D-glucuronidase, and β-D-galactosidase. The most potent of the stimulatory glycans is a β-1,3-D-glucan isolated from yeast cell walls. Up to 50% of total enzyme activity was found in the medium after stimulation with this glycan for three days. Agarose, another insoluble glycan containing an alternating sequence of the disaccharide β-1,3-D-galactose-α-1,4-3,6-anhydro-L-galactose units was less potent. The soluble β-1,3-D-glucan laminaran, which also contains small amounts of mannitol, was not able to induce release of acid glycosidases from macrophages. The release was independent of serum since macrophages cultured under serum-free conditions showed nearly the same pattern of enzyme activities, both in the cells and media. There was no increased release of the acid hydrolase α-D-mannosidase after stimulation with the insoluble β-1,3-D-gluc...

Developmental & Comparative Immunology, 1989

Journal of Fish Diseases

ABSTRACT

The mucosal surfaces are the first barrier against systemic infection of bacteria. Bacteria may f... more The mucosal surfaces are the first barrier against systemic infection of bacteria. Bacteria may find their way to and through the skin, gills, eye and gastrointestinal (GI) tract. Some bacteria may induce disease symptoms in the mucosal surfaces, while others form 'disease foci' in internal organs and tissues. In this review emphasis has been put on GI tract infections as this organ represents one of the most important portals of entry of numerous bacterial species. Infection through the GI tract is multifactorial and requires several stages: potential pathogens must be able to survive gastric transit, outcompete commensal gut microbiota, survive and colonize the intestinal mucus, and finally colonize and breach the intestinal brush border. The precise mechanisms underpinning these processes for a number of pathogens are partly described. Although we are becoming increasingly informed about the mucosal immune responses of fish, there remains a paucity of information regarding production of cytokines or expression of cytokine mRNAs in the GI tract during natural pathogen outbreaks. In response to experimental bath challenges however it is evident that immune responses may be stimulated, resulting in increased expression of certain pro-inflammatory cytokines (e.g. IL-1β and TNF-α) in the oral mucosae. The use of prebiotics, and probiotics, offers a means to fortify the gut microbiota, potentiate the intestinal immune response and reduce intestinal pathogenesis. Roy.Dalmo@uit.no

Journal of Fish Diseases

. Proteases produced by Vibrio anguillarum were isolated from culture supernatant by ultrafiltrat... more . Proteases produced by Vibrio anguillarum were isolated from culture supernatant by ultrafiltration, gel chromatography and ion exchange chromatography. The enzyme(s) were shown to be collagenolytic when assayed with native collagen substrates. In addition, the enzyme(s) hydrolysed azocasein, azocollagen, the collagenase substrate 4-phenylazobenzyloxycarbonyl-Pro-Leu-Gly-Pro-D-Arg and the aminopeptidase substrate L-Leu-pNA effectively. Separation of the proteases by Mono Q ion exchange chromatography and native polyacrylamide gel electrophoresis revealed four distinct protein bands containing caseinase activity. However, only two of the bands showed aminopeptidase activity. The aminopeptidase activities could be separated from the caseinase activities by isoelectric focusing. Secreted proteases of different serotypcs of V. anguillarum showed a heterogeneous caseinolytic pattern. The molecular mass of the major enzyme was estimated at 35kDa as determined by its mobility on SDS-polya...

The mucosal surfaces are the first barrier against systemic infection of bacteria. Bacteria may f... more The mucosal surfaces are the first barrier against systemic infection of bacteria. Bacteria may find their way to and through the skin, gills, eye and gastrointestinal (GI) tract. Some bacteria may induce disease symptoms in the mucosal surfaces, while others form 'disease foci' in internal organs and tissues. In this review emphasis has been put on GI tract infections as this organ represents one of the most important portals of entry of numerous bacterial species. Infection through the GI tract is multifactorial and requires several stages: potential pathogens must be able to survive gastric transit, outcompete commensal gut microbiota, survive and colonize the intestinal mucus, and finally colonize and breach the intestinal brush border. The precise mechanisms underpinning these processes for a number of pathogens are partly described. Although we are becoming increasingly informed about the mucosal immune responses of fish, there remains a paucity of information regarding production of cytokines or expression of cytokine mRNAs in the GI tract during natural pathogen outbreaks. In response to experimental bath challenges however it is evident that immune responses may be stimulated, resulting in increased expression of certain pro-inflammatory cytokines (e.g. IL-1β and TNF-α) in the oral mucosae. The use of prebiotics, and probiotics, offers a means to fortify the gut microbiota, potentiate the intestinal immune response and reduce intestinal pathogenesis. Roy.Dalmo@uit.no

Journal of Fish Diseases, Mar 24, 2013

Gene expression profiling has opened new directions of investigative immunobiology (Appay et al. ... more Gene expression profiling has opened new directions of investigative immunobiology (Appay et al. 2007). T-cell-derived cytokines are major determinants of the outcome of immune responses (Sakkas et al. 1998). The existence of the basic effector Thl, Th2, Treg and Th17 subsets is now well accepted in mammalian immunology and is being exploited to plan therapeutic and vaccination strategies. However, we do not yet know the full extent of T-cell diversity and the nature of the initial signals that determines the T-cell response pattern in teleosts. Thus, to understand the basis of protective immunity and the molecular mechanisms involved in activation of T-cell-mediated immune response (at the transcript level) during immunization of fish using oil-based vaccines, we investigated gene transcription profile of cytokines indicative of the presence of the different T-cell subsets Th1/Th2/ Treg/Th17, transcription factors for Th1/Th2 and specific T-cell marker CD8a, prior to and following vaccination with oil-adjuvanted A. salmonicida subspecies salmonicida or infectious pancreatic necrosis virus (IPNV) in Atlantic salmon. Oiladjuvanted vaccines have shown to be effective against furunculosis (Midtlyng 1997) and IPNV (Hill & Dixon 1977) in challenge trials. Atlantic salmon, Salmo salar L. (80–100 g), were kept at the Aquaculture Research Station (Tromsø, Norway) in circular 500L tanks supplied with recirculating fresh water at an ambient temperature of approximately 10 °C with 12/12 h illumination and fed a commercial pellet diet. Eighty fish were placed in each tank per group, and the fish were acclimatized for 2 weeks prior to vaccination. Prior to vaccination, fish were anaesthetized in 0.005% benzocaine. Fish were killed using 0.01% benzocaine prior to collection of different tissues. The experiment was approved by ‘FDU’ (http://www. mattilsynet.no/fdu/) to be in accordance with the animal welfare act as required by Norwegian law. Vaccination was done i.p, with 0.1 mL of preparation fish . The different vaccine preparations used in this study are shown in Table 1. All experimental preparations were supplied by PHARMAQ AS. The oil-adjuvanted inactivated preparations were formulated as water-in-oil emulsions (W/O), where the water phase with the antigens was dispersed into an oil phase. Group A served as negative control (without adjuvant and antigen) and group B as adjuvant control (without antigen). Spleen and head kidney tissues were sampled aseptically from fish of all groups at 1, 2, 5, 7, 14 and 28 days postvaccination (dpv), immediately transferred to RNAlater (Ambion) and stored at 20 °C. Total RNA extraction and real-time PCR were conducted as previously described (Kumari, Bogwald & Dalmo 2009). For each mRNA, gene expression was normalized to the elongation factor 1a (EF1a) mRNA content using the Pfaffl method (Pfaffl 2001). The primers used are shown in Table 2. The log-transformed data were analysed by ANOVA and a Tukey’s multiple range test to determine the differences between groups using SYSTAT 13. For testing of significance of correlation between the Correspondence J Kumari and R A Dalmo, Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, N-9037 Tromsø, Norway (e-mails: jaya.kumari@uit.no and roy.dalmo@uit.no)

Biology

The overexpression of GATA-3, T-bet and TGF-ß may theoretically induce IL-4/A, IFN-γ and IL-17A e... more The overexpression of GATA-3, T-bet and TGF-ß may theoretically induce IL-4/A, IFN-γ and IL-17A expression, respectively. Whether this also applies to fish is not yet known. The plasmid vectors encoding reporter gene (RFP)-tagged T-bet, GATA-3 and TGF-ß were used as overexpression tools, transfected into cells or injected intramuscularly to monitor the expression of IFN-γ, IL-4/13A and IL-17A. In addition, the fish were either experimentally challenged with Vibrio anguillarum (VA group) or Piscirickettsia salmonis (PS group). The reporter gene (RFP) inserted upstream of the GATA-3, T-bet and TGF-ß genes, was observed in muscle cell nuclei and in inflammatory cells after intramuscular (i.m.) injection. PS group: following the injection of GATA-3 and T-bet-encoding plasmids, the expression of GATA-3 and T-bet was high at the injection site. The spleen expression of IFN-γ, following the injection of a T-bet-encoding plasmid, was significantly higher on day 2. VA group: The T-bet and GA...

Principles of Fish Immunology, 2022

Research on the innate immunity has accelerated over the last decades. The main reason for this h... more Research on the innate immunity has accelerated over the last decades. The main reason for this has been the discovery of receptors recognizing danger molecules from pathogens. This has been facilitated through genome and transcriptome sequencing of different fish species. Also, endogenous host molecules from sterile physiological insults may also bind to certain receptors and induce immunological processes. The magnitude and quality of adaptive immunity are known to be dependent on the instructions the innate response gives. This chapter gives an overview of selected innate immune organs/tissues, factors, and processes that have been suggested to possess important roles during innate immune response in fish.

Journal of Fish Diseases, 2021

The vertebrates (Figure 1) are a subphylum of the chordata, characterized by the possession of a ... more The vertebrates (Figure 1) are a subphylum of the chordata, characterized by the possession of a brain enclosed in a skull, ears, kidney and other organs. In most vertebrates, a well-formed bony or cartilaginous vertebral column or backbone is enclosing the spinal cord (Lawrence, 1997). Fish constitute more than one-half of the total number of approximately 48,000 recognized vertebrate species living today. The teleosts (modern bony fishes) represent the majority. The remainders are elasmobranch (sharks and rays, approximately 700 species) and about 170 other species (Nelson, 1994). Studies in fish, amphibians and reptiles have recently revealed that even these vertebrates carry a specialized endothelium that carry out a scavenger function corresponding to that of the rat liver endothelial cells (Seternes et al., 2002). An overview over the anatomical distribution of soluble markers and the presence of scavenger endothelial cells in different fish is presented in Table 1.

International Journal of Molecular Sciences, 2021

Immersion and intraperitoneal injection are the two most common methods used for the vaccination ... more Immersion and intraperitoneal injection are the two most common methods used for the vaccination of fish. Because both methods require that fish are handled and thereby stressed, oral administration of vaccines as feed supplements is desirable. In addition, in terms of revaccination (boosting) of adult fish held in net pens, oral administration of vaccines is probably the only feasible method to obtain proper protection against diseases over long periods of time. Oral vaccination is considered a suitable method for mass immunization of large and stress-sensitive fish populations. Moreover, oral vaccines may preferably induce mucosal immunity, which is especially important to fish. Experimental oral vaccine formulations include both non-encapsulated and encapsulated antigens, viruses and bacteria. To develop an effective oral vaccine, the desired antigens must be protected against the harsh environments in the stomach and gut so they can remain intact when they reach the lower gut/in...

Microorganisms, 2019

Immersion vaccines are used for a variety of aquacultured fish to protect against infectious dise... more Immersion vaccines are used for a variety of aquacultured fish to protect against infectious diseases caused by bacteria and viruses. During immersion vaccination the antigens are taken up by the skin, gills or gut and processed by the immune system, where the resulting response may lead to protection. The lack of classical secondary responses following repeated immersion vaccination may partly be explained by the limited uptake of antigens by immersion compared to injection. Administration of vaccines depends on the size of the fish. In most cases, immersion vaccination is inferior to injection vaccination with regard to achieved protection. However, injection is problematic in small fish, and fry as small as 0.5 gram may be immersion vaccinated when they are considered adaptively immunocompetent. Inactivated vaccines are, in many cases, weakly immunogenic, resulting in low protection after immersion vaccination. Therefore, during recent years, several studies have focused on diffe...

Fish Vaccines, 2016

Vaccination is the most appropriate method to control infectious diseases that threaten the aquac... more Vaccination is the most appropriate method to control infectious diseases that threaten the aquaculture industry worldwide. Unfortunately, vaccines are usually not able to confer protection on their own, especially those vaccines based on recombinant antigens or inactivated pathogens. Therefore, the use of adjuvants or immunostimulants is often necessary to increase vaccine efficacy. Furthermore, an important additional problem that limits the entry of novel fish vaccines to the market is that many of the vaccines experimentally produced only work when injected (either intraperitoneally or intramuscularly). Therefore, the search for alternative methods of mass vaccine delivery (oral or immersion) should also be addressed in parallel. Unfortunately, it is probable that the search for a specific combination of antigen/adjuvant/delivery method has to be experimentally addressed for each pathogen/fish species, and only a few general conclusions can be drawn from each of these studies. In this chapter, we summarise previous studies performed with both traditional and new generation adjuvants as well as those studies that have explored methods for vaccine delivery alternative to injection.

Developmental and comparative immunology, Jan 4, 2015

The RAR-related orphan receptors (RORs) are members of the nuclear receptor family of intracellul... more The RAR-related orphan receptors (RORs) are members of the nuclear receptor family of intracellular transcription factors. In this study, we examined the regulatory properties of RORα (CsRORα) and RORγ (CsRORγ) in tongue sole (Cynoglossus semilaevis). CsRORα and CsRORγ expression was detected in major lymphoid organs and altered to significant extents after bacterial and viral infection. CsRORα enhanced the activities of CsIL-17C, CsIL-17D, and CsIL-17F promoters, which contain CsRORα and CsRORγ binding sites. CsRORγ also upregulated the promoter activities of CsIL-17D and CsIL-17F but not CsIL-17C. CsRORα and CsRORγ proteins were detected in the nucleus, and overexpression of CsRORα in tongue sole significantly increased the expression of CsIL-17C, CsIL-17D, and CsIL-17F, whereas overexpression of CsRORγ significantly increased the expression of CsIL-17C and CsIL-17F but no CsIL-17D. These results indicate that RORα and RORγ in teleost regulate the expression of IL-17 members in di...

Infectious Disease in Aquaculture, 2012

Abstract: Use of injection vaccines plays a key role in controlling infectious diseases in the aq... more Abstract: Use of injection vaccines plays a key role in controlling infectious diseases in the aquaculture industry. Since 1990 oil-adjuvanted vaccines have been the most widespread and most efficacious vaccines available. However, side effects such as retardation in growth, pigmentation and adherence of intestines have initiated a search for new adjuvants, even though considerable advances with respect to adverse side effects have been achieved during the latest years. Experimental vaccines have included immunostimulants such as beta-glucans, polyinosinic polycytidylic acid (poly I:C), CpG, flagellin, and cytokines free or encapsulated in polymers/particles. Encapsulation of vaccines in biodegradable poly(lactic-co-glycolic acid (PLGA) is especially intriguing.

Fish & Shellfish Immunology, 1996

The uptake and distribution ofAeromonas salmonicidalipopolysaccharide (LPS) in Atlantic salmon,Sa... more The uptake and distribution ofAeromonas salmonicidalipopolysaccharide (LPS) in Atlantic salmon,Salmo salarL., was investigated. The purified LPS molecule was radiolabelled by bromine oxidation and subsequent sodium borotritide reduction, or fluorescein labelled. After intravenous injection, high amounts of radiolabelled LPS was found in the spleen, liver, anterior and posterior kidneys at 30 min and 2h. Twenty four hours after i.v. administration, the spleen still contained high amounts of radioactivity, the liver contained increased amounts while the anterior and posterior kidneys showed reduced contents of radioactivity compared with the findings 30 min and 2h after administration. After peroral administration, relatively less radioactive LPS accumulated in the liver compared with the spleen and kidneys at 0·5, 1, 4 and 24h. At 24 and 48h after administration the anterior intestine contained high amounts of radioactivity while the posterior intestine contained low amounts. Histological examinations of tissue sections revealed accumulation of fluorescein-labelled LPS in kidney sinusoidal endothelial cells and macrophages and in splenic ellipsoid sheath cells (macrophages and reticular cells). Liver endothelial cells also showed accumulation of FITC-LPS.

Fish & Shellfish Immunology, 2000

Radiolabelled bacterial lipopolysaccharide (3 H-LPS) obtained from Aeromonas salmonicida subsp. s... more Radiolabelled bacterial lipopolysaccharide (3 H-LPS) obtained from Aeromonas salmonicida subsp. salmonicida was added to the petri dishes containing yolk sac larvae of Atlantic halibut (Hippoglossus hippoglossus L.). The larvae were exposed either to 6•25, 12•5, 25, 50 or 100 g 3 H-LPS ml 1. The uptake was both dependent on the LPS concentration and the time of exposure. After 5 days of exposure, each larva contained 1•8-7•4 ng 3 H-LPS dependent on the initial concentration. After 10 days of exposure each larva contained 7•0-12•4 ng LPS and after 15 days they contained 18•3-34•9 ng 3 H-LPS. Fluorescence microscopic analysis of sections obtained from larvae exposed to FITC-LPS (25, 50 and 100 g ml 1) for 5, 10 and 15 days, revealed fluorescence in intestinal epithelial cells, cells in the connective tissue adjacent to the intestine, in cells located between the integumental layer and yolk sac, and in some epithelial cells in the integument. By use of immunohistochemical techniques, LPS was confined to intestinal epithelial cells, lumen of excretory duct and in numerous cells in the epidermal layer. Control specimens did not contain fluorescence or were immunohistochemically negative for LPS. In groups of larvae exposed to 12•5, 25, 50 and 100 g LPS ml 1 , the survival was significantly increased after exposure to 50 and 100 g LPS ml 1 from day 20 (96 d) and throughout the yolk sac period compared to untreated larvae.

Fish & Shellfish Immunology, 2011

Foxp3 is a T cell-specific transcription factor and plays a key role in the development of Treg c... more Foxp3 is a T cell-specific transcription factor and plays a key role in the development of Treg cells and in the immune regulatory process during inflammation. Here we report cloning and characterization of the full-length cDNA of Atlantic salmon Foxp3, which possesses a Forkhead domain, a zinc finger domain and a leucine-zipper domain as its counterpart in mammals. Foxp3 is highly expressed in thymus. Furthermore, regulated expression was observed in head kidney cells in response to β-glucan and mitogens (LPS and ConA), and in the head kidney, spleen and liver after intraperitoneal injection of live Aeromonas salmonicida. In addition, transfection of CHSE-214 cells with salmon Foxp3 fused with a C-termial RFP tag, resulted in the expression of the transgene in and close to the nuclei upon stimulation. Taken together, these results suggest the presence of a Foxp3 gene in Atlantic salmon that may be an important transcription factor in immune regulation, and further research may reveal the existence of Treg-like T cells in this species.

Journal of Leukocyte Biology, 1984

Mouse peritoneal macrophages stimulated with insoluble glycans in vitro release high amounts of a... more Mouse peritoneal macrophages stimulated with insoluble glycans in vitro release high amounts of acid hydrolases, N-acetyl-β-D-glucosaminidase, β-D-glucuronidase, and β-D-galactosidase. The most potent of the stimulatory glycans is a β-1,3-D-glucan isolated from yeast cell walls. Up to 50% of total enzyme activity was found in the medium after stimulation with this glycan for three days. Agarose, another insoluble glycan containing an alternating sequence of the disaccharide β-1,3-D-galactose-α-1,4-3,6-anhydro-L-galactose units was less potent. The soluble β-1,3-D-glucan laminaran, which also contains small amounts of mannitol, was not able to induce release of acid glycosidases from macrophages. The release was independent of serum since macrophages cultured under serum-free conditions showed nearly the same pattern of enzyme activities, both in the cells and media. There was no increased release of the acid hydrolase α-D-mannosidase after stimulation with the insoluble β-1,3-D-gluc...

Developmental & Comparative Immunology, 1989

Journal of Fish Diseases

ABSTRACT

The mucosal surfaces are the first barrier against systemic infection of bacteria. Bacteria may f... more The mucosal surfaces are the first barrier against systemic infection of bacteria. Bacteria may find their way to and through the skin, gills, eye and gastrointestinal (GI) tract. Some bacteria may induce disease symptoms in the mucosal surfaces, while others form 'disease foci' in internal organs and tissues. In this review emphasis has been put on GI tract infections as this organ represents one of the most important portals of entry of numerous bacterial species. Infection through the GI tract is multifactorial and requires several stages: potential pathogens must be able to survive gastric transit, outcompete commensal gut microbiota, survive and colonize the intestinal mucus, and finally colonize and breach the intestinal brush border. The precise mechanisms underpinning these processes for a number of pathogens are partly described. Although we are becoming increasingly informed about the mucosal immune responses of fish, there remains a paucity of information regarding production of cytokines or expression of cytokine mRNAs in the GI tract during natural pathogen outbreaks. In response to experimental bath challenges however it is evident that immune responses may be stimulated, resulting in increased expression of certain pro-inflammatory cytokines (e.g. IL-1β and TNF-α) in the oral mucosae. The use of prebiotics, and probiotics, offers a means to fortify the gut microbiota, potentiate the intestinal immune response and reduce intestinal pathogenesis. Roy.Dalmo@uit.no

Journal of Fish Diseases

. Proteases produced by Vibrio anguillarum were isolated from culture supernatant by ultrafiltrat... more . Proteases produced by Vibrio anguillarum were isolated from culture supernatant by ultrafiltration, gel chromatography and ion exchange chromatography. The enzyme(s) were shown to be collagenolytic when assayed with native collagen substrates. In addition, the enzyme(s) hydrolysed azocasein, azocollagen, the collagenase substrate 4-phenylazobenzyloxycarbonyl-Pro-Leu-Gly-Pro-D-Arg and the aminopeptidase substrate L-Leu-pNA effectively. Separation of the proteases by Mono Q ion exchange chromatography and native polyacrylamide gel electrophoresis revealed four distinct protein bands containing caseinase activity. However, only two of the bands showed aminopeptidase activity. The aminopeptidase activities could be separated from the caseinase activities by isoelectric focusing. Secreted proteases of different serotypcs of V. anguillarum showed a heterogeneous caseinolytic pattern. The molecular mass of the major enzyme was estimated at 35kDa as determined by its mobility on SDS-polya...

The mucosal surfaces are the first barrier against systemic infection of bacteria. Bacteria may f... more The mucosal surfaces are the first barrier against systemic infection of bacteria. Bacteria may find their way to and through the skin, gills, eye and gastrointestinal (GI) tract. Some bacteria may induce disease symptoms in the mucosal surfaces, while others form 'disease foci' in internal organs and tissues. In this review emphasis has been put on GI tract infections as this organ represents one of the most important portals of entry of numerous bacterial species. Infection through the GI tract is multifactorial and requires several stages: potential pathogens must be able to survive gastric transit, outcompete commensal gut microbiota, survive and colonize the intestinal mucus, and finally colonize and breach the intestinal brush border. The precise mechanisms underpinning these processes for a number of pathogens are partly described. Although we are becoming increasingly informed about the mucosal immune responses of fish, there remains a paucity of information regarding production of cytokines or expression of cytokine mRNAs in the GI tract during natural pathogen outbreaks. In response to experimental bath challenges however it is evident that immune responses may be stimulated, resulting in increased expression of certain pro-inflammatory cytokines (e.g. IL-1β and TNF-α) in the oral mucosae. The use of prebiotics, and probiotics, offers a means to fortify the gut microbiota, potentiate the intestinal immune response and reduce intestinal pathogenesis. Roy.Dalmo@uit.no