Heilongjiang River Fishery Research Institute Chinese Academy of Fishery Sciences, Harbin, 150070, PR China.
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, PR China.
Mol Immunol. 2019 Dec;116:180-190. doi: 10.1016/j.molimm.2019.10.015. Epub 2019 Nov 5.
Infectious pancreatic necrosis virus (IPNV) and infectious hematopoietic necrosis virus (IHNV) are two common viral pathogens that cause severe economic losses in all salmonid species in culture, but especially in rainbow trout. Although vaccines against both diseases have been commercialized in some countries, no such vaccines are available for them in China. In this study, a recombinant virus was constructed using the IHNV U genogroup Blk94 virus as a backbone vector to express the antigenic gene, VP2, from IPNV via the reverse genetics system. The resulting recombinant virus (rBlk94-VP2) showed stable biological characteristics as confirmed by virus growth kinetic analyses, pathogenicity analyses, indirect immunofluorescence assays and western blotting. Rainbow trout were immunized with rBlk94-VP2 and then challenged with the IPNV ChRtm213 strain and the IHNV Sn1203 strain on day 45 post-vaccination. A significantly higher survival rate against IHNV was obtained in the rBlk94-VP2 group on day 45 post-vaccination (86%) compared with the PBS mock immunized group (2%). Additionally, IPNV loads decreased significantly in the rBlk94-VP2 immunized group in the liver (28.6-fold to 36.5-fold), anterior kidney (21.7-fold to 44.2-fold), and spleen (14.9-fold to 22.7-fold), as compared with the PBS mock control group. The mRNA transcripts for several innate and adaptive immune-related proteins (IFN-γ, IFN-1, Mx-1, CD4, CD8, IgM, and IgT) were also significantly upregulated after rBlk94-VP2 vaccination, and neutralizing antibodies against both IHNV and IPNV were induced on day 45 post-vaccination. Collectively, our results suggest that this recombinant virus could be developed as a vaccine vector to protect rainbow trout against two or more diseases, and our approach lays the foundations for developing live vaccines for rainbow trout.
传染性胰脏坏死病毒 (IPNV) 和传染性造血器官坏死病毒 (IHNV) 是两种常见的病毒病原体，它们会导致所有养殖鲑鱼物种（尤其是虹鳟）遭受严重的经济损失。尽管这两种疾病的疫苗已在一些国家商业化，但中国尚未有针对它们的疫苗。在本研究中，我们使用 IHNV U 基因群 Blk94 病毒作为骨干载体，通过反向遗传学系统表达 IPNV 的抗原基因 VP2，构建了一种重组病毒。通过病毒生长动力学分析、致病性分析、间接免疫荧光和 Western blot 验证，该重组病毒（rBlk94-VP2）显示出稳定的生物学特性。虹鳟在第 45 天接种 rBlk94-VP2 后，分别用 IPNV ChRtm213 株和 IHNV Sn1203 株攻毒，第 45 天 rBlk94-VP2 组的 IHNV 攻毒保护率（86%）显著高于 PBS 对照组（2%）。此外，与 PBS 对照组相比，rBlk94-VP2 免疫组虹鳟肝脏（28.6 倍至 36.5 倍）、前肾（21.7 倍至 44.2 倍）和脾脏（14.9 倍至 22.7 倍）中的 IPNV 载量显著降低。与 PBS 对照组相比，rBlk94-VP2 免疫组虹鳟几种固有和适应性免疫相关蛋白（IFN-γ、IFN-1、Mx-1、CD4、CD8、IgM 和 IgT）的 mRNA 转录本也显著上调，接种后第 45 天诱导产生针对 IHNV 和 IPNV 的中和抗体。总之，我们的研究结果表明，该重组病毒可作为疫苗载体，用于保护虹鳟抵抗两种或更多疾病，为虹鳟活疫苗的开发奠定了基础。
