JIA-2019-11

Journal of Integrative Agriculture 2019, 18(11): 2598–2604 RESEARCH ARTICLE Available online at www.sciencedirect.com ScienceDirect Baculovirus-expressed FAdV-4 penton base protein protects chicken against hepatitis-hydropericardium syndrome ZHANG Jun-qin 1, 2* , WEI Yan-ming 1, 2, 3* , HUANG Kun 1, 2 , SUN Xiao-mei 1, 2, 3 , ZOU Zhong 1, 2, 3 , JIN Mei-lin 1, 2, 3 1 State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, P.R.China 2 College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, P.R.China 3 Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Wuhan 430070, P.R.China Abstract Hepatitis-hydropericardium syndrome (HHS) is an infectious disease caused by fowl adenovirus serotype 4 (FAdV-4). Several structural and non-structural proteins of FAdV-4 have been expressed in Escherichia coli and baculovirus expression system to develop candidate subunit vaccines. However, the protective efficiency of baculovirus-expressed penton base protein has not been assessed. In this study, two recombinant capsid proteins, penton base and fiber-2, were constructed. And then, penton base and fiber-2 were administrated alone or together to specific pathogen-free (SPF) chickens at 14 days of life and boosted at 28 days of life. At 42 days of life, the immunized groups and the control group were challenged with FAdV-4 virulent strain. Results show that inoculating penton base or penton base+fiber-2 provided 100% protection to the chickens. All groups vaccinated with the recombinant protein produced detectable antibodies and showed no apparent lesions. Thus, baculovirus-expressed penton base protein is a promising candidate subunit vaccine. Keywords: fowl adenovirus serotype 4, hepatitis - hydropericardium syndrome, penton base, subunit vaccine, baculovirus expression system City, Pakistan (Khawaja et al . 1988), so it is also named as Ankara disease. Fowl adenovirus serotype 4 (FAdV-4) is the causative agent of HHS; this virus causes hydropericardium and hepatitis with basophilic intra-nuclear inclusion bodies in chickens (Kim et al . 2008). The icosahedral-shaped capsid of FAdV-4 contains three major structural proteins, namely, hexon, penton base, and fiber (Harrison et al . 2010). These proteins play an essential role in the early stages of adenovirus infection, particularly in cell binding and cell entry (Medina-Kauwe et al . 2003). The FAdV-4 capsid contains 252 subunits, with hexons forming its 240 facets and fibers protruding from its 12 vertices. Penton is at the base of fiber (Valentine and Pereira 1965; Gelderblom and Maichle- Lauppe 1982; Stewart et al . 1991; Marek et al . 2012). Cell binding is initially triggered by fiber interacting with primary Received 29 December, 2018 Accepted 9 June, 2019 Correspondence JIN Mei-lin, E-mail: jml8328@126.com; ZOU Zhong, E-mail: zz19841024@126.com * These authors contributed equally to this study. © 2019 CAAS. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/) . doi: 10.1016/S2095-3119(19)62739-5 1. Introduction Hepatitis-hydropericardium syndrome (HHS) is an infectious disease in poultry and is characterized by sudden onset, and mortality of up to 80% in 3–6 weeks old broilers (Chandra et al . 2000) . This disease first broke out in 1987 in Ankara