Abstract：
Infectious hematopoietic necrosis virus (IHNV) and infectious pancreatic necrosis virus (IPNV) are typical pathogens of rainbow trout Oncorhynchus mykiss, and the concurrent infection of the two viruses is very common among modern trout hatcheries, which has caused huge economic losses to the rainbow trout farming industry. To prevent and control the spread of IHNV and IPNV in juvenile trout simultaneously, in this study a bivalent recombinant adenovirus vaccine with IHNV Glycoprotein (G) and IPNV VP2 genes was developed. After immunizing juvenile trout with this bivalent vaccine via the immersion route, the expression levels of IHNV G and IPNV VP2 and the representative immune genes in vaccinated and control rainbow trout were tested to evaluate the correlation of immune responses with the expression of viral genes. The neutralizing antibody level induced by this bivalent vaccine as well as the protection efficacy of the vaccine against IHNV and IPNV was also evaluated. The results showed that IHNV G and IPNV VP2 were successfully expressed in juvenile trout, and all the innate and adaptive immune genes were up-regulated. This indicated that the level of the innate and adaptive immune responses were significantly increased, which might be induced by the high expression of the two viral proteins. Compared with the controls, high levels of neutralizing antibodies against IHNV and IPNV were induced in the vaccinated trout. Besides, the bivalent recombinant adenovirus vaccine showed high protection rate against IHNV, with the relative percent survival (RPS) of 81.25%, as well as against IPNV, with the RPS of 78.95%. Taken together, our findings clearly demonstrated that replication-defective adenovirus can be developed as a qualified vector for fish vaccines and IHNV G and IPNV VP2 were two suitable antigenic genes that could induce effective immune protection against these two pathogens. This study provided new insights into developing bivalent vectored vaccines and controlling the spread of IHNV and IPNV simultaneously in juvenile trout.
摘要：
传染性造血系统坏死病毒(IHNV)和传染性胰腺坏死病毒(IPNV)是虹鳟鱼Oncorhynchusmykiss的典型病原体,这两种病毒的同时感染在现代鳟鱼孵化场中非常普遍，这给虹鳟鱼养殖业造成了巨大的经济损失。同时预防和控制IHNV和IPNV在鳟鱼幼鱼中的传播，在这项研究中，开发了具有IHNV糖蛋白（G）和IPNVVP2基因的二价重组腺病毒疫苗。用这种二价疫苗通过浸泡途径免疫幼鱼后，检测了IHNVG和IPNVVP2的表达水平以及接种和对照虹鳟鱼中的代表性免疫基因，以评估免疫应答与病毒基因表达的相关性。还评估了由该二价疫苗诱导的中和抗体水平以及疫苗对IHNV和IPNV的保护效力。结果表明，IHNVG和IPNVVP2在鳟鱼幼鱼中成功表达，所有的先天和适应性免疫基因都上调。这表明先天和适应性免疫反应的水平显着增加，这可能是由两种病毒蛋白的高表达诱导的。与对照组相比，在接种疫苗的鳟鱼中诱导了高水平的抗IHNV和IPNV的中和抗体.此外,双价重组腺病毒疫苗对IHNV有较高的保护率,相对存活率（RPS）为81.25%，以及反对IPNV，RPS为78.95%。一起来看,我们的研究结果清楚地表明，复制缺陷型腺病毒可以开发为合格的鱼苗载体，IHNVG和IPNVVP2是两个合适的抗原基因，可以诱导针对这两种病原体的有效免疫保护。这项研究为开发二价载体疫苗以及同时控制IHNV和IPNV在幼鱼中的传播提供了新的见解。
