Bruce Timothy J, Ma Jie, Knupp Christopher, Loch Thomas P, Faisal Mohamed, Cain Kenneth D
Department of Fish and Wildlife Sciences, College of Natural Resources, University of Idaho, Moscow, ID, USA.
Department of Fisheries and Wildlife, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI, USA.
J Fish Dis. 2020 Aug;43(8):915-928. doi: 10.1111/jfd.13201. Epub 2020 Jun 18.
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.
对于鲑科鱼类养殖者来说，一个常见的威胁是嗜冷黄杆菌。细菌性冷水病（BCWD）管理方面的最新进展包括开发出一种减毒活浸浴疫苗，该疫苗可对一系列嗜冷黄杆菌菌株提供交叉保护。与临床疾病相关的黄杆菌科新发病例一直在增加，包括黄杆菌属和金黄杆菌属的致病分离株。测定了一种嗜冷黄杆菌减毒活疫苗对三种有毒力的黄杆菌科分离株的交叉保护能力。对幼年虹鳟进行疫苗接种，使其产生高嗜冷黄杆菌特异性抗体滴度，然后用金黄杆菌属分离株（S25和T28）、一种黄杆菌属（S21）分离株、S21:S25:T28的混合组合以及标准有毒力的嗜冷黄杆菌CSF259-93菌株进行攻毒。结果表明，与相关的CSF259-93对照组相比，接种CSF259-93疫苗的组具有很强的保护作用（相对百分存活率（RPS）=94.44%）（p <.001）。在用S21:S25:T28混合物攻毒的接种疫苗鱼中也观察到了保护作用（RPS = 85.18%；p <.001）。然而，单独使用S21、S25或T28分离株时未观察到保护作用。全细胞裂解物分析显示，通过SDS-PAGE分析蛋白条带存在差异，但通过蛋白质印迹法分析发现S25和T28中存在保守的抗原区域。结果表明，这种减毒活疫苗对混合黄杆菌感染具有保护作用，并提示对黄杆菌病有进一步的益处。
