Tilapia lake virus (TiLV) is the main tilapia-infecting virus worldwide, causing serious economic losses to the tilapia aquaculture. However, there is no vaccine for this viral disease. Here, TiLV ORF10 (TiLV-ORF10) encoding a protein with abundant epitopes was cloned into the eukaryotic expression vector pcDNA3.1 as a vaccine candidate, and then used to evaluate the protective effects against TiLV in Nile tilapia (Oreochromis niloticus). RT-PCR and Western blot analyses confirmed pcDNA3.1–ORF10 expression in tilapia. The transcription levels of immunity-related genes such as immunoglobulin M, Toll-like receptor 2, myeloid differentiation factor 88, interleukin 8, tumor necrosis factor alpha, gamma-IFN, and nuclear factor κB were significantly upregulated in the spleen, liver, and kidney of the vaccinated tilapias (P < 0.05). TiLV challenge experiments showed that relative percent survival (RPS) was significantly enhanced in fish vaccinated with the DNA vaccine. Moreover, the RPS was significantly higher in fish vaccinated with a high dose of the DNA vaccine (85.72% RPS at a dosage of 45 μg DNA vaccine plasmid). Meanwhile, vaccination with pcDNA3.1–ORF10 significantly reduced virus replication, as evidenced by the lower amount of virus in the spleen, liver, and kidney of vaccinated tilapia than tilapias vaccinated with the empty pcDNA3.1 plasmid. Thus, pcDNA3.1–ORF10 could induce protective immunity in tilapia and may be a potential vaccine candidate for controlling disease caused by TiLV.

罗非鱼湖病毒（TiLV）是全球主要的罗非鱼感染病毒，给罗非鱼养殖业造成严重的经济损失。然而，没有针对这种病毒性疾病的疫苗。在这里，将编码具有丰富表位的蛋白质的TiLV ORF10（TiLV-ORF10）作为候选疫苗克隆到真核表达载体pcDNA3.1中，然后用于评估尼罗罗非鱼（Oreochromis niloticus）对TiLV的保护作用。RT-PCR 和蛋白质印迹分析证实了 pcDNA3.1-ORF10 在罗非鱼中的表达。免疫球蛋白M、Toll样受体2、骨髓分化因子88、白细胞介素8等免疫相关基因的转录水平、肿瘤坏死因子α、γ-干扰素和核因子κB在接种罗非鱼的脾脏、肝脏和肾脏中显着上调（P < 0.05）。TiLV 挑战实验表明，接种 DNA 疫苗的鱼的相对存活百分比 (RPS) 显着提高。此外，接种高剂量 DNA 疫苗的鱼的 RPS 显着升高（45 μg DNA 疫苗质粒剂量为 85.72% RPS）。同时，接种 pcDNA3.1–ORF10 显着降低了病毒复制，与接种空 pcDNA3.1 质粒的罗非鱼​​相比，接种罗非鱼脾脏、肝脏和肾脏中的病毒量较低就证明了这一点。因此，pcDNA3.1-ORF10 可以在罗非鱼中诱导保护性免疫，并可能成为控制由 TiLV 引起的疾病的潜在候选疫苗。