Acta Veterinaria et Zootechnica Sinica ›› 2020, Vol. 51 ›› Issue (10): 2463-2471.doi: 10.11843/j.issn.0366-6964.2020.10.014

• PREVENTIVE VETERINARY MEDICINE • Previous Articles     Next Articles

Isolation and Identification of Group I Type 4 Avian Adenovirus and Analysis in Immune Effect of Fiber-2 Protein

CHENG Zengqing1,2, FAN Gencheng2, DOU Xiaolong2, LIU Hongxiang2, SHEN Maoxin2, XU Quangang3, YANG Hanchun1*   

  1. 1. College of Veterinary Medicine, China Agricultural University, Beijing 100193, China;
    2. State Key Laboratory of Animal Genetic Engineering Vaccine/YEBIO Bioengineering Co., Ltd of Qingdao, Qingdao 266114, China;
    3. China Animal Health and Epidemiology Center, Qingdao 266032, China
  • Received:2020-03-30 Online:2020-10-25 Published:2020-10-26

Abstract: The aim of this study was to identify pathogens, which caused pericardial effusion, hepatomegaly and bleeding at a chicken farm in Henan province, and furthermore to analyze effectiveness of immunogenic proteins of the pathogen. This study employed virus isolation, serological assays, PCR and sequencing analysis, animal experimentation, E. coli expression and protein purification, immunogenicity and challenge test and other methods. The results showed that virus was isolated in 7-day-old SPF chicken embryonated eggs, inoculated via the yolk sac route by two blind passages. Viral confirmation was carried out using PCR techniques, and showed a 900-bp-long fragment which shared a 100% homology with the Hexon gene of the serotype C4 strain. Serum neutralization results indicated that this isolate avian adenovirus was the group I type 4 avian adenovirus, named HN-ZK strain. The virus could induce CPE on primary hepatocytes of chicken embryo, and its titer was 107.5 TCID50·0.1 mL-1. Animal experimentation illustrated that the isolated virus caused 100% (10/10) typical symptoms and pathogenicity in 35-day-old SPF chickens. Furthermore, the DNA of the isolate virus was used as a template to express Fiber-2 fragment, with a molecular weight of 33 kDa by using the E. coli expression system, and the protein was concentrated and purified to 300 mg·mL-1 after centrifugation and purification. SPF chickens were immunized with different doses of the purified Fiber-2 protein, and showed that a dose of 20 μg per chick was completely resistant to challenge of the virulent virus, suggesting the purified Fiber-2 protein has better immunogenicity. This study can provide data for diagnosing the hydropericardium hepatitis syndrome, and developing a genetic engineering subunit vaccine.

Key words: group I avian adenovirus, identification, fiber-2 protein, subunit vaccine

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