Graduate Program in Pathobiology, Department of Global Health, University of Washington, Seattle, WA 98195, USA.
Fish Shellfish Immunol. 2011 Jul;31(1):43-51. doi: 10.1016/j.fsi.2011.03.003. Epub 2011 Mar 6.
Infectious hematopoietic necrosis virus (IHNV) is a fish rhabdovirus that causes significant mortality in salmonid species. In North America IHNV has three major genogroups designated U, M, and L. Host-specificity of the M and U genogroups of IHNV has been established both in the field and in experimental challenges, with M isolates being more prevalent and more virulent in rainbow trout (Oncorhynchus mykiss), and U isolates being more prevalent and highly virulent in sockeye salmon (Oncorhynchus nerka). In this study, efficacy of DNA vaccines containing either M (pM) or U (pU) virus glycoprotein genes was investigated during intra- and cross-genogroup challenges in rainbow trout. In virus challenges at 7 days post-vaccination (early antiviral response), both pM and pU were highly protective against either M or U IHNV. In challenges at 28 days post-vaccination (specific antiviral response), both pM and pU were protective against M IHNV but the homologous pM vaccine was significantly more protective than pU in one of two experiments. At this stage both pM and pU induced comparably high protection against U IHNV challenge. Correlates of protection were also investigated by assessing the expression of the interferon-stimulated gene Mx-1 and the production of neutralizing antibodies (NAbs) following pM or pU DNA vaccination. Mx-1 gene expression, measured at 4 and 7 days post-vaccination as an indicator of the host innate immune response, was found to be significantly higher after pM than pU vaccination in some cases. Neutralizing antibody was produced in response to the two vaccines, but antibody titers did not show consistent correlation with protection. The results show that the rainbow trout innate and adaptive immune responses have some ability to distinguish between the U and M genogroup IHNV, but overall the pM and pU vaccines were protective against both homologous and cross-genogroup challenges.
传染性造血器官坏死病毒（IHNV）是一种鱼类弹状病毒，可导致鲑鱼物种大量死亡。在北美，IHNV 有三个主要的基因型，分别命名为 U、M 和 L。在现场和实验性挑战中，已经确定了 M 和 U 基因型 IHNV 的宿主特异性，M 分离株在虹鳟（Oncorhynchus mykiss）中更为普遍和更具毒性，而 U 分离株在红大麻哈鱼（Oncorhynchus nerka）中更为普遍和高度毒性。在这项研究中，在虹鳟的内和跨基因型挑战中，研究了含有 M（pM）或 U（pU）病毒糖蛋白基因的 DNA 疫苗的功效。在疫苗接种后 7 天（早期抗病毒反应）的病毒挑战中，pM 和 pU 对 M 或 U IHNV 均具有高度保护作用。在疫苗接种后 28 天（特异性抗病毒反应）的挑战中，pM 和 pU 对 M IHNV 具有保护作用，但在两个实验中的一个实验中，同源的 pM 疫苗比 pU 具有显著更高的保护作用。在这个阶段，pM 和 pU 对 U IHNV 挑战均诱导了相当高的保护作用。通过评估干扰素刺激基因 Mx-1 的表达和 pM 或 pU DNA 疫苗接种后的中和抗体（NAb）的产生，也研究了保护相关因素。Mx-1 基因表达，作为宿主先天免疫反应的指标，在疫苗接种后 4 天和 7 天进行测量，在某些情况下，pM 比 pU 疫苗接种后明显更高。针对两种疫苗产生了中和抗体，但抗体滴度与保护作用没有一致的相关性。结果表明，虹鳟的先天和适应性免疫反应具有区分 U 和 M 基因型 IHNV 的一定能力，但总体而言，pM 和 pU 疫苗对同源和跨基因型挑战均具有保护作用。
