College of Veterinary Medicine, Gansu Agricultural University, 1# Yingmencun Road, Lanzhou, 730070, China.
Center for Fisheries Technology Promotion, 533# Duanjiatan Road, Lanzhou, 730020, China.
Fish Shellfish Immunol. 2019 Jun;89:516-524. doi: 10.1016/j.fsi.2019.04.024. Epub 2019 Apr 12.
Infectious hematopoietic necrosis virus (IHNV) leads to serious disease and economic losses in the salmonid aquaculture industry. The present study aimed to develop an effective and efficient vaccine to protect rainbow trout (Oncorhynchus mykiss) against IHNV infection. Administered via the immersion route, a live vector vaccine containing the regions of the IHNV glycoprotein (G) induced immune responses in rainbow trout. Use of the immersion route induced more-efficient mucosal immunity than intramuscular injection vaccination. IHNV G gene expression was detected in the spleens of rainbow trout at 3, 7 and 15 days post-vaccination (dpv). The G gene expression continuously decreased between 3 and 15 dpv. In addition, the expression of TLR-3, TLR-7 and TLR-8 was upregulated after vaccination, and the highest expression levels of IFN-1, Mx-1, Mx-3, Vig-1 and Vig-2 were observed at 3 dpv. Four markers of the adaptive immune response (CD4, CD8, IgM and IgT) gradually increased. When experimental fish were challenged with IHNV by immersion, significant differences in cumulative percentage mortality were observed in the vaccinated fish and the unvaccinated (empty-plasmid-vaccinated) fish. The relative survival rate was 92% and 6% in the vaccinated group and empty-plasmid group, respectively. Serum antibody levels gradually increased in the vaccinated fish, unlike in the unvaccinated fish, after 7 dpv. Our results suggest there was a significant increase in fish immune responses and resistance to infection with IHNV following administration of the live vector vaccine. Therefore, this live vector vaccine is a promising vaccine that may be utilized to protect rainbow trout against IHNV.
传染性造血器官坏死病毒 (IHNV) 可导致鲑鱼养殖业发生严重疾病并造成经济损失。本研究旨在开发一种有效的疫苗，以保护虹鳟鱼（Oncorhynchus mykiss）免受 IHNV 感染。通过浸泡途径给予的含有 IHNV 糖蛋白（G）区域的活载体疫苗可诱导虹鳟鱼产生免疫应答。与肌肉内注射疫苗相比，浸泡途径可诱导更有效的黏膜免疫。在接种后 3、7 和 15 天（dpv），虹鳟鱼脾脏中检测到 IHNV G 基因表达。G 基因表达在 3 至 15 dpv 之间连续下降。此外，接种后 TLR-3、TLR-7 和 TLR-8 的表达上调，IFN-1、Mx-1、Mx-3、Vig-1 和 Vig-2 的表达水平在 3 dpv 时最高。适应性免疫应答的四个标志物（CD4、CD8、IgM 和 IgT）逐渐增加。当实验鱼通过浸泡用 IHNV 进行攻毒时，在接种疫苗的鱼和未接种疫苗（空质粒接种）的鱼之间观察到累积死亡率的显著差异。接种组和空质粒组的相对存活率分别为 92%和 6%。在接种疫苗的鱼中，血清抗体水平在 7 dpv 后逐渐增加，而在未接种疫苗的鱼中则没有。我们的结果表明，给予活载体疫苗后，虹鳟鱼的免疫反应和对 IHNV 的抵抗力显著增强。因此，这种活载体疫苗是一种有前途的疫苗，可用于保护虹鳟鱼免受 IHNV 感染。
