DEVELOPMENT OF A DETECTIVE HEPATITIS A VIRUS VACCINE

迄今为止，生产HAV疫苗的尝试尚未成功，原因是 几个因素包括病毒在组织培养中生长不良， 缺乏减毒的体外标志物，以及分离的 病毒蛋白不显示病毒中和表位。 作为 经典灭活病毒或减毒病毒疫苗的替代品 方法或重组DNA衍生的亚单位疫苗，缺陷型HAV 这种方法将被开发和测试作为甲型肝炎疫苗。 甲型肝炎病毒新毒株 导致溶解性感染并在组织培养中生长到高滴度的病毒将 被利用 在第一阶段，这种快速增长的HAV变体的基因组将被 克隆，并评估分离克隆的生物活性 通过转染到易感的人肝癌细胞中。 在第二阶段， 缺失或取代突变将被引入到2C区， 基因组来产生有缺陷的HAV。 互补细胞系 将构建表达2C基因的细胞，并用于生长缺陷的 病毒 一旦缺陷病毒和互补细胞系被 构建，研究，以评估突变病毒的稳定性和 病毒的生产水平将进行，以确定 将病毒用作疫苗的可行性。

Attempts to generate HAV vaccines have been unsuccessful to date due to several factors including poor growth of the virus in tissue culture, absence of in vitro markers of attenuation, and the fact that isolated viral proteins do not display virus neutralizing epitopes. As an alternative to classical killed virus or a attenuated virus vaccine approaches or recombinant DNA derived subunit vaccines, a defective HAV approach will be developed and tested as a HAV vaccine. A new HAV strain that causes lytic infection and grows to high titer in tissue culture will be used. In Phase I, the genome of this fast growing HAV variant will be cloned and the biological activity of the isolated clone will be assessed by transfection into susceptible human hepatoma cells. In Phase II, deletion or substitution mutations will be introduced into the 2C region of the genome to generate a defective HAV. A complementing cell line expressing the 2C gene will be constructed and used to grow the defective virus. Once the defective virus and complementing cell line are constructed, studies to assess the stability of the mutant virus and the production level of the virus will be done in order to determine the feasibility of using the virus as a vaccine.