State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; Key Laboratory of Aquaculture Disease Control, Ministry of Agriculture, Wuhan, China.
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China; University of Chinese Academy of Sciences, Beijing, China.
Fish Shellfish Immunol. 2018 Apr;75:66-73. doi: 10.1016/j.fsi.2018.01.047. Epub 2018 Jan 31.
Grass carp reovirus II (GCRV II) causes severe hemorrhagic disease with high mortality in grass carp, Cyenopharyngodon idellus. DNA vaccination has been proven to be a very effective method in conferring protection against fish viruses. However, DNA vaccines for GCRV II have not yet been conducted on grass carp. In the current work, we vaccinated grass carp with a DNA vaccine consisting of the segment 6 (pC-S6; encoding VP4) or 10 (pC-S10; encoding NS38) of GCRV II and comparatively analyzed the immune responses induced by these two vaccines. The protective efficacy of pC-S6 and pC-S10, in terms of relative percentage survival (RPS), was 59.9% and 23.1% respectively. This suggests that pC-S6 and pC-S10 DNA vaccines could increase the survival rate of grass carp against GCRV, albeit with variations in immunoprotective effect. Immunological analyses indicated the following. First, post-vaccination (pv), both pC-S6 and pC-S10 up-regulated the expression of interferon (IFN-1), Mx1, IL-1β, and TNF-α. However, CD4 and CD8α were up-regulated in the case of pC-S6 but not pC-S10. Second, comparing non-vaccinated and pC-S10-vaccinated fish, the T cell response related genes, such as CD4, CD8α, and GATA3, were elevated in pC-S6-vaccinated fish at 48 h post-challenge (pc). Third, pC-S6 and pC-S10 induced similar patterns of specific antibody response pv. However, only anti-VP4 IgM in the sera of surviving fish infected with GCRV was significantly increased pc compared with that pre-challenge. Taken together, these results indicate that pC-S6 promotes both innate (IFN-1 and Mx1 induction) and adaptive (T cell and specific antibody response) immunity pv and that the induction of a memory state promptly primes the immune response upon later encounters with the virus, whereas pC-S10 only induces the type I IFN-related response pv and a lower inflammatory response pc.
草鱼出血病病毒 Ⅱ 型（GCRV II）可引起草鱼严重出血性疾病，死亡率很高。DNA 疫苗已被证明是一种非常有效的方法，可以对鱼类病毒提供保护。然而，针对 GCRV II 的 DNA 疫苗尚未在草鱼上进行过。在目前的工作中，我们用一种包含 GCRV II 片段 6（pC-S6；编码 VP4）或 10（pC-S10；编码 NS38）的 DNA 疫苗对草鱼进行了免疫接种，并比较分析了这两种疫苗所诱导的免疫反应。pC-S6 和 pC-S10 的保护效力（以相对存活率（RPS）表示）分别为 59.9%和 23.1%。这表明，pC-S6 和 pC-S10 DNA 疫苗可以提高草鱼对 GCRV 的存活率，但免疫保护效果存在差异。免疫分析表明：首先，接种后（pv），pC-S6 和 pC-S10 均上调了干扰素（IFN-1）、Mx1、IL-1β 和 TNF-α的表达。然而，只有 pC-S6 上调了 CD4 和 CD8α的表达，而 pC-S10 则没有。其次，与未接种和 pC-S10 接种的鱼相比，在 pC-S6 接种的鱼中，CD4、CD8α 和 GATA3 等 T 细胞反应相关基因在感染 GCRV 后 48 小时（pc）升高。第三，pC-S6 和 pC-S10 在 pv 时诱导了相似的特异性抗体反应模式。然而，只有在幸存的鱼的血清中，感染 GCRV 后抗-VP4 IgM 显著升高，与挑战前相比。综上所述，这些结果表明，pC-S6 促进了先天（IFN-1 和 Mx1 诱导）和适应性（T 细胞和特异性抗体反应）免疫 pv，并且在随后遇到病毒时迅速引发免疫反应的记忆状态，而 pC-S10 仅诱导 I 型干扰素相关反应 pv 和较低的炎症反应 pc。
