Singh Ankit, Saxena Gauri, Verma Praveen C
National Research Centre on Plant Biotechnology, Pusa Campus, New Delhi, 110012, India.
Department of Botany, University of Lucknow, Lucknow, 226007, India.
Methods Mol Biol. 2016;1404:547-567. doi: 10.1007/978-1-4939-3389-1_36.
Vaccination is the sensitization process of the immune system against any pathogen. Generally, recombinant subunit vaccines are considered safer than attenuated vaccines. As whole pathogenic organisms are used in the immunization process, the attenuated vaccines are considered more risky than subunit vaccines. Rabies is the oldest known zoonosis which spreads through a neurotropic Lyssavirus primarily mediated through infected canine bites. Rabies causes worldwide loss of more than 60,000 human lives every year. Animal vaccination is equally important to check the transmission of rabies into humans. Rabies oral vaccination can be a good alternative where multiple booster and priming regimens are required while the painful vaccination process can continue for long durations. Introduction of oral vaccines was made to ease the discomfort associated with the mode of introduction of conventional vaccines into the body. Although the rabies oral vaccine can substantially reduce the cost of vaccination in the developing countries, mass immunization programs need larger quantities of vaccines which should be delivered at nominal cost. Expression of recombinant antigen proteins in E. coli is often not viable because of lack of post-translational modifications and folding requirements. Though yeast and insect cell line expression systems have post-translational processing and modifications, significantly different immunological response against their post-translational modification pattern limits their deployment as an expression system. As an alternative, plants are emerging as a promising system to express and deliver wide range of functionally active biopharmaceutical product at lower cost for mass immunization programs. As generation of vaccine antigenic proteins in plant systems are cheaper, the strategy will benefit developing countries where this disease causes thousands of deaths every year. In this chapter, we will discuss about our efforts toward development of oral rabies vaccine and the methodological steps involved during this procedure in detail.
疫苗接种是免疫系统针对任何病原体的致敏过程。一般来说，重组亚单位疫苗被认为比减毒活疫苗更安全。由于在免疫过程中使用的是完整的致病生物体，减毒活疫苗被认为比亚单位疫苗风险更大。狂犬病是已知最古老的人畜共患病，它通过嗜神经性狂犬病病毒传播，主要通过感染的犬类咬伤介导。狂犬病每年在全球导致超过6万人死亡。动物疫苗接种对于控制狂犬病向人类的传播同样重要。在需要多次加强和初免方案且痛苦的接种过程可能持续很长时间的情况下，狂犬病口服疫苗可能是一个很好的选择。口服疫苗的引入是为了减轻与传统疫苗引入体内方式相关的不适。尽管狂犬病口服疫苗可以大幅降低发展中国家的疫苗接种成本，但大规模免疫计划需要大量疫苗，且应以较低成本提供。由于缺乏翻译后修饰和折叠要求，在大肠杆菌中表达重组抗原蛋白通常不可行。尽管酵母和昆虫细胞系表达系统具有翻译后加工和修饰，但针对其翻译后修饰模式的显著不同的免疫反应限制了它们作为表达系统的应用。作为一种替代方案，植物正成为一种有前景的系统，能够以较低成本表达和提供广泛的功能活性生物制药产品，用于大规模免疫计划。由于在植物系统中生产疫苗抗原蛋白成本较低，该策略将使每年因这种疾病导致数千人死亡的发展中国家受益。在本章中，我们将详细讨论我们在开发口服狂犬病疫苗方面所做的努力以及该过程中涉及的方法步骤。
