Tembusu virus (TMUV) is a contagious pathogen of waterfowl including ducks and geese, which causes symptoms of high fever, loss of appetite and reduced egg production. The development of an effective vaccine is important for the prevention and control of the disease. We evaluated a DNA vaccine based on a recombinant pre-membrane (prM) and envelope (E) protein, using CpG oligodeoxynucleotide (ODN) as an adjuvanted, and tested it for protection efficacy. BHK21 cells were transfected with the recombinant plasmid pVAX1-prM/E-CpG, and the antigenicity of the expressed protein was detected using an indirect immunofluorescence assay (IFA) and western blot assay. One-day-old ducklings were intramuscularly injected with 200 μg doses of pVAX1-prM/E-CpG or pVAX1-CpG, or PBS at ten day intervals. The neutralizing antibodies and cell-mediated immune responses elicited by the DNA vaccine were detected using serum neutralization tests (SNTs) and ELISAs. At 20 days old, the ducks were challenged with 103EID50 doses of TMUV SD/02 strain and observed for 15 days post challenge. After the second DNA vaccination and during the monitoring period, the levels of TMUV neutralizing antibodies increased in the pVAX1-prM/E-CpG vaccinated ducks. Vaccination with pVAX1-prM/E-CpG resulted in 100.0% protection of the ducks, whereas approximately 40% of ducks vaccinated with pVAX-CpG or PBS manifested clinical symptoms. Expressions of IFN-γ and IL-6 in the pVAX1-prM/E-CpG group were significantly increased (p <  0.01) compared with the control groups during the entire experimental period. The results revealed that a vaccine co-expressing prM and E, and using a CpG-ODN motif as an adjuvant, could elicit effective neutralizing antibody titers and provide efficient protection to ducks against TMUV infection.

中文翻译：

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CpG佐剂的DNA疫苗针对Tembusu病毒的免疫原性和保护效果的评估。

Tembusu病毒（TMUV）是水禽（包括鸭和鹅）的传染性病原体，可引起高烧，食欲不振和产蛋减少的症状。开发有效的疫苗对于预防和控制该疾病很重要。我们使用CpG寡脱氧核苷酸（ODN）作为佐剂，评估了基于重组前膜（prM）和包膜（E）蛋白的DNA疫苗，并测试了其保护效果。用重组质粒pVAX1-prM / E-CpG转染BHK21细胞，并使用间接免疫荧光法（IFA）和蛋白质印迹法检测表达的蛋白质的抗原性。以10天的间隔肌肉注射1天大的小鸭200克剂量的pVAX1-prM / E-CpG或pVAX1-CpG或PBS。使用血清中和试验（SNT）和ELISA检测由DNA疫苗引起的中和抗体和细胞介导的免疫反应。在20天大时，用103EID50剂量的TMUV SD / 02菌株攻击鸭子，并在攻击后观察15天。在第二次DNA疫苗接种后和监测期间，pVAX1-prM / E-CpG免疫鸭子中TMUV中和抗体的水平增加。用pVAX1-prM / E-CpG进行疫苗接种可保护鸭子100.0％，而接种pVAX-CpG或PBS的鸭子中约有40％表现出临床症状。在整个实验期间，与对照组相比，pVAX1-prM / E-CpG组中的IFN-γ和IL-6的表达明显增加（p <0.01）。结果表明，疫苗共表达prM和E，