Cross-protection of a live-attenuated Flavobacterium psychrophilum immersion vaccine against novel Flavobacterium spp. and Chryseobacterium spp. strains |
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Authors: | Timothy J Bruce Jie Ma Christopher Knupp Thomas P Loch Mohamed Faisal Kenneth D Cain |
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Institution: | 1. Department of Fish and Wildlife Sciences, College of Natural Resources, University of Idaho, Moscow, ID, USA;2. Department of Fisheries and Wildlife, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI, USA;3. Department of Fisheries and Wildlife, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI, USA
Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA |
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Abstract: | For salmonid producers, a common threat is Flavobacterium psychrophilum. Recent advancements in bacterial coldwater disease (BCWD) management include the development of a live-attenuated immersion vaccine that cross-protects against an array of F. psychrophilum strains. Emerging family Flavobacteriaceae cases associated with clinical disease have been increasing, including pathogenic isolates of Flavobacterium spp. and Chryseobacterium spp. The cross-protective ability of a live-attenuated F. psychrophilum vaccine was determined against three virulent Flavobacteriaceae isolates. Juvenile rainbow trout were vaccinated, developed high F. psychrophilum-specific antibody titres and were challenged with Chryseobacterium spp. isolates (S25 and T28), a Flavobacterium sp. (S21) isolate, a mixed combination of S21:S25:T28, and a standard virulent F. psychrophilum CSF259-93 strain. Results demonstrated strong protection in the CSF259-93 vaccinated group (relative per cent survival (RPS)=94.44%) when compared to the relevant CSF259-93 controls (p < .001). Protection was also observed for vaccinated fish challenged with the S21:S25:T28 mix (RPS = 85.18%; p < .001). However, protection was not observed with the S21, S25 or T28 isolates alone. Analysis of whole-cell lysates revealed differences in protein banding by SDS-PAGE, but conserved antigenic regions by Western blot in S25 and T28. Results demonstrate that this live-attenuated vaccine provided protection against mixed flavobacterial infection and suggest further benefits against flavobacteriosis. |
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Keywords: | attenuated vaccine Chryseobacterium spp cross-protection Flavobacterium spp |
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