An efficacious recombinant subunit vaccine against the salmonid rickettsial pathogen Piscirickettsia salmonis.
Piscirickettsia salmonis is the aetiological agent of salmonid rickettsial septicaemia, an economically devastating rickettsial disease of farmed salmonids. Infected salmonids respond poorly to antibiotic treatment and no effective vaccine is available for the control of P. salmonis. Bacterin preparations of P. salmonis were found to elicit a dose-dependent response in coho salmon (Oncorhynchus kisutch), which varied from inadequate protection to exacerbation of the disease. However, an outer surface lipoprotein of P. salmonis, OspA, recombinantly produced in Escherichia coli elicited a high level of protection in vaccinated coho salmon with a relative percent survival as high as 59% for this single antigen. In an effort to further improve the efficacy of the OspA recombinant vaccine, T cell epitopes (TCE's) from tetanus toxin and measles virus fusion protein, that are universally immunogenic in mammalian immune systems, were incorporated tandemly into an OspA fusion protein. Addition of these TCE's dramatically enhanced the efficacy of the OspA vaccine, reflected by a three-fold increase in vaccine efficacy. These results represent a highly effective monovalent recombinant subunit vaccine for a rickettsia-like pathogen, P. salmonis, and for the first time demonstrate the immunostimulatory effect of mammalian TCE's in the salmonid immune model. These results may also be particularly pertinent to salmonid aquaculture in which the various subspecies are outbred and of heterologous haplotypes.
Canadian Bacterial Diseases Network, Department of Biochemistry and Microbiology, University of Victoria, PO Box 3055, British Columbia V8W 3P6, Victoria, Canada.
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MA
Kuzyk
J
J
Burian
D
D
Machander
D
D
Dolhaine
S
S
Cameron
J C
JC
Thornton
W W
WW
Kay
D000595:Amino Acid Sequence; D000818:Animals; D000954:Antigens, Surface / Q000235:genetics / Q000276:immunology; D001424:Bacterial Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology; D001428:Bacterial Vaccines / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D005393:Fish Diseases / Q000276:immunology / Q000517:prevention & control; D005398:Fisheries; D020563:Gammaproteobacteria / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D008074:Lipoproteins; D022123:Lyme Disease Vaccines / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D017684:Oncorhynchus kisutch; D012487:Salmonidae / Q000382:microbiology*; D013601:T-Lymphocytes / Q000276:immunology; D022223:Vaccines, Subunit / Q000235:genetics / Q000276:immunology / Q000494:pharmacology
D000954:Antigens, Surface; D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D008074:Lipoproteins; D022123:Lyme Disease Vaccines; C072045:OspA protein; D022223:Vaccines, Subunit