Subunit vaccine candidates against Aeromonas salmonicida in rainbow trout Oncorhynchus mykiss.
Aeromonas salmonicida subsp. salmonicida is the etiological agent of furunculosis and a major fish health problem in salmonid aquaculture worldwide. Injection vaccination with commercial mineral oil-adjuvanted bacterin vaccines has been partly successful in preventing the disease but in Danish rainbow trout (Oncorhynchus mykiss, Walbaum) aquaculture furunculosis outbreaks still occur. In this study we tested the efficacy of experimental subunit vaccines against A. salmonicida infection in rainbow trout. We utilized in silico screening of the proteome of A. salmonicida subsp. salmonicida strain A449 and identified potential protective protein antigens that were tested by in vivo challenge trial. A total of 14 proteins were recombinantly expressed in Escherichia coli and prepared in 3 different subunit vaccine combinations to immunize 3 groups of rainbow trout by intraperitoneal (i.p.) injection. The fish were exposed to virulent A. salmonicida 7 weeks after immunization. To assess the efficacy of the subunit vaccines we evaluated the immune response in fish after immunization and challenge infection by measuring the antibody levels and monitoring the survival of fish in different groups. The survival of fish at 3 weeks after challenge infection showed that all 3 groups of fish immunized with 3 different protein combinations exhibited significantly lower mortalities (17-30%) compared to the control groups (48% and 56%). The ELISA results revealed significantly elevated antibody levels in fish against several protein antigens, which in some cases were positively correlated to the survival.
Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
Moonika Haahr
http://orcid.org/0000-0003-3535-6341
MH
Marana
Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
Louise von Gersdorff
LV
Jørgensen
Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
Jakob
J
Skov
National Veterinary Institute, Technical University of Denmark, Denmark.
Jiwan Kumar
JK
Chettri
Evaxion Biotech, Copenhagen, Denmark.
Andreas
A
Holm Mattsson
National Veterinary Institute, Technical University of Denmark, Denmark.
Inger
I
Dalsgaard
Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
Per Walter
PW
Kania
Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
Kurt
K
Buchmann
D048409:Aeromonas salmonicida / Q000276:immunology* / Q000472:pathogenicity; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology; D005393:Fish Diseases / Q000276:immunology* / Q000517:prevention & control; D016905:Gram-Negative Bacterial Infections / Q000276:immunology* / Q000517:prevention & control; D007114:Immunization / Q000379:methods; D017686:Oncorhynchus mykiss / Q000276:immunology* / Q000382:microbiology; D020543:Proteome / Q000276:immunology; D022223:Vaccines, Subunit / Q000276:immunology*
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D020543:Proteome; D022223:Vaccines, Subunit