Guo H, Zhou E M, Sun Z F, Meng X J
Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
Vaccine. 2007 Apr 12;25(15):2892-9. doi: 10.1016/j.vaccine.2006.09.038. Epub 2006 Sep 25.
Avian hepatitis E virus (avian HEV) is an emerging virus associated with hepatitis-splenomegaly syndrome in chickens in North America. Avian HEV is genetically and antigenically related to human HEV, the causative agent of hepatitis E in humans. In the lack of a practical animal model, avian HEV infection in chickens has been used as a model to study human HEV replication and pathogenesis. A 32 kDa recombinant ORF2 capsid protein of avian HEV expressed in Escherichia coli was found having similar antigenic structure as that of human HEV containing major neutralizing epitopes. To determine if the capsid protein of avian HEV can be used as a vaccine, 20 chickens were immunized with purified avian HEV recombinant protein with aluminum as adjuvant and another 20 chickens were mock immunized with KLH precipitated in aluminum as controls. Both groups of chickens were subsequently challenged with avian HEV. All the tested mock-immunized control chickens developed typical avian HEV infection characterized by viremia, fecal virus shedding and seroconversion to avian HEV antibodies. Gross hepatic lesions were also found in portion of these chickens. In contrast, none of the tested chickens immunized with avian HEV capsid protein had detectable viremia, fecal virus shedding or observable gross hepatitis lesions. The results from this study suggested that immunization of chickens with avian HEV recombinant ORF2 capsid protein with aluminum as adjuvant can induce protective immunity against avian HEV infection. Chickens are a useful small animal model to study anti-HEV immunity and pathogenesis.
禽戊型肝炎病毒（avian HEV）是一种新出现的病毒，与北美鸡的肝炎-脾肿大综合征有关。禽戊型肝炎病毒在基因和抗原方面与人类戊型肝炎病毒相关，后者是人类戊型肝炎的病原体。由于缺乏实用的动物模型，鸡的禽戊型肝炎病毒感染已被用作研究人类戊型肝炎病毒复制和发病机制的模型。在大肠杆菌中表达的禽戊型肝炎病毒32 kDa重组ORF2衣壳蛋白被发现具有与含有主要中和表位的人类戊型肝炎病毒相似的抗原结构。为了确定禽戊型肝炎病毒的衣壳蛋白是否可用作疫苗，用纯化的禽戊型肝炎病毒重组蛋白加铝作为佐剂免疫20只鸡，另外20只鸡用铝沉淀的钥孔戚血蓝蛋白（KLH）进行模拟免疫作为对照。随后两组鸡都用禽戊型肝炎病毒进行攻毒。所有测试的模拟免疫对照鸡都出现了典型的禽戊型肝炎病毒感染，其特征为病毒血症、粪便病毒排出以及血清转化为禽戊型肝炎病毒抗体。在这些鸡中部分还发现了明显的肝脏病变。相比之下，用禽戊型肝炎病毒衣壳蛋白免疫的测试鸡中没有一只检测到病毒血症、粪便病毒排出或明显的肝炎病变。这项研究的结果表明，用铝作为佐剂的禽戊型肝炎病毒重组ORF2衣壳蛋白免疫鸡可以诱导针对禽戊型肝炎病毒感染的保护性免疫。鸡是研究抗戊型肝炎病毒免疫和发病机制的有用小动物模型。
