Henriques Ana M, Fevereiro Miguel, Monteiro Gabriel A
Laboratory of Virology, Instituto Nacional de Investigação Agrária e Veterinária, Lisbon, Portugal.
Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Lisbon, Portugal.
Methods Mol Biol. 2016;1404:59-76. doi: 10.1007/978-1-4939-3389-1_4.
Maedi-visna virus (MVV) is an ovine retrovirus of the Lentivirus genus, responsible for a chronic and progressive disease of sheep with a high prevalence all over the world. Therefore, measures aiming at the control of MVV infection are necessary, and the development of DNA vaccines may be the ideal approach. A DNA vaccine is an antigen-encoding bacterial plasmid designed to mimic infections safely, with ability to generate both humoral and cellular long-lasting immune responses once it is delivered to the host.Here, we describe the development and evaluation of DNA vaccines against ovine maedi-visna virus. The first step is the design of the vaccines, including the choice of the backbone vector and the nucleotide sequences to use as antigen-encoding sequences. Once constructed, the vaccines may be produced with high quality for use in in vitro and in vivo tests. In vitro assays are performed through transfection of animal cells to confirm the expression of the protein, while in vivo tests are carried out by mouse and/or sheep immunization in order to check humoral and cellular responses to the vaccines and conclude about their efficiency. Several approaches may be later performed in order to enhance the effectiveness of the vaccines, such as the introduction of targeting sequences, the use of a prime-boost strategy, the administration of a combined vaccine, and the use of liposomes as delivery vehicle.
梅迪-维斯纳病毒（MVV）是慢病毒属的一种绵羊逆转录病毒，可引发一种在全球范围内高发性的绵羊慢性进行性疾病。因此，采取旨在控制MVV感染的措施很有必要，而开发DNA疫苗可能是理想的方法。DNA疫苗是一种编码抗原的细菌质粒，旨在安全地模拟感染，一旦递送至宿主，就能产生持久的体液免疫和细胞免疫反应。在此，我们描述针对绵羊梅迪-维斯纳病毒的DNA疫苗的开发与评估。第一步是疫苗的设计，包括载体骨架的选择以及用作抗原编码序列的核苷酸序列的选择。构建完成后，可高质量生产疫苗用于体外和体内试验。体外试验通过转染动物细胞来进行，以确认蛋白质的表达，而体内试验则通过对小鼠和/或绵羊进行免疫来开展，以检查对疫苗的体液免疫和细胞免疫反应，并得出关于其有效性的结论。为提高疫苗的有效性，后续可采用多种方法，如引入靶向序列、使用初免-加强策略、接种联合疫苗以及使用脂质体作为递送载体。
