Universidad de Málaga, Instituto de Biotecnología y Desarrollo Azul, IBYDA, Área De Genética, Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias, 29071, Málaga, Spain; Universidad de Málaga, Instituto de Biotecnología y Desarrollo Azul, IBYDA Departamento de Microbiología, Facultad de Ciencias, 29071, Málaga, Spain.
Universidad de Málaga, Instituto de Biotecnología y Desarrollo Azul, IBYDA Departamento de Microbiología, Facultad de Ciencias, 29071, Málaga, Spain.
Comp Immunol Microbiol Infect Dis. 2020 Apr;69:101426. doi: 10.1016/j.cimid.2020.101426. Epub 2020 Jan 28.
Viral Haemorrhagic Septicaemia Virus (VHSV) isolates virulent to marine fish species can replicate in freshwater species, although producing little or no mortality. Conversely, isolates from freshwater fish do not cause disease in marine species. An inverse relationship between VHSV virulence and host mx gene up-regulation has been described for several fish species, suggesting that differences between the antagonistic activity exerted by these isolates might be involved in the outcome of infections. In this study, the antagonistic activity against the type I interferon system of two representative marine and freshwater VHSV isolates has been characterised using RTG-2 cells stably transfected with the luciferase gene under the control of the Senegalese sole mx (ssmx) promoter, RTG pssmx-luc cells. Both isolates exerted a dose-dependent negative effect on the activation of ssmx promoter, showing a notably different minimal viral dose to exert the antagonism. In particular, an inverse relationship between the minimal MOI required and the viral virulence to sole has been recorded, which suggests this parameter as a possible in vivo VHSV virulence marker. Furthermore, the quantification of the endogenous inf I, mx1 and mx3 mRNA has demonstrated differences between both isolates in their antagonistic activity. Besides, a different nv RNA kinetics, which seems to depend on specific cellular factors, has been recorded for both isolates. This knowledge could contribute to the development of efficient tools to fight against viral infections in fish farming. For that purpose, the RTG pssmx-luc cells may be a suitable in vitro tool to identify the molecular mechanisms underlying VHSV-host interactions.
病毒性出血性败血症病毒 (VHSV) 对海洋鱼类具有毒性的分离株可以在淡水物种中复制，尽管产生的死亡率很低或没有。相反，来自淡水鱼类的分离株不会引起海洋物种的疾病。已经描述了几种鱼类的 VHSV 毒力与宿主 mx 基因上调之间的反比关系，这表明这些分离株所施加的拮抗活性的差异可能参与了感染的结果。在这项研究中，使用稳定转染了荧光素酶基因的 RTG-2 细胞，通过 Senegalese sole mx (ssmx) 启动子、RTG pssmx-luc 细胞来表征两种代表性的海洋和淡水 VHSV 分离株对 I 型干扰素系统的拮抗活性。这两种分离株都对 ssmx 启动子的激活表现出剂量依赖性的负效应，表现出明显不同的最小病毒剂量来发挥拮抗作用。特别是，记录到所需最小 MOI 与对 sole 的病毒毒力之间存在反比关系，这表明该参数可能是体内 VHSV 毒力的标志物。此外，对两种分离株的内源性 inf I、mx1 和 mx3 mRNA 的定量分析表明，它们在拮抗活性方面存在差异。此外，还记录到两种分离株的 nv RNA 动力学不同，这似乎取决于特定的细胞因子。这些知识可能有助于开发有效的工具来对抗鱼类养殖中的病毒感染。为此，RTG pssmx-luc 细胞可能是识别 VHSV-宿主相互作用的分子机制的合适体外工具。
