Antigenic properties of avian hepatitis E virus capsid protein.
Avian hepatitis E virus (HEV) is the main causative agent of big liver and spleen disease and hepatitis-splenomegaly syndrome in chickens, and is genetically and antigenically related to mammalian HEVs. HEV capsid protein contains immunodominant epitopes and induces a protective humoral immune response. A better understanding of the antigenic composition of this protein is critically important for the development of effective vaccine and sensitive and specific serological assays. To date, six linear antigenic domains (I-VI) have been characterized in avian HEV capsid protein and analyzed for their applications in the serological diagnosis and vaccine design. Domains I and V induce strong immune response in chickens and are common to avian, human, and swine HEVs, indicating that the shared epitopes hampering differential diagnosis of avian HEV infection. Domains III and IV are not immunodominant and elicit a weak immune response. Domain VI, located in the N-terminal region of the capsid protein, can also trigger an intense immune response, but the anti-domain VI antibodies are transient. The protection analysis showed that the truncated capsid protein containing the C-terminal 268 amino acid residues expressed by the bacterial system can provide protective immunity against avian HEV infection in chickens. However, the synthetic peptides incorporating the different linear antigenic domains (I-VI) and epitopes are non-protective. The antigenic composition of avian HEV capsid protein is altogether complex. To develop an effective vaccine and accurate serological diagnostic methods, more conformational antigenic domains or epitopes are to be characterized in detail.
Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling 712100, Shaanxi, China.
Qin
Q
Zhao
Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling 712100, Shaanxi, China.
Shahid Faraz
SF
Syed
Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling 712100, Shaanxi, China. Electronic address: zhouem@nwsuaf.edu.cn.
En-Min
EM
Zhou
D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000737:chemistry / Q000276:immunology; D036022:Capsid Proteins / Q000737:chemistry / Q000276:immunology*; D002645:Chickens / Q000821:virology*; D006524:Hepatitis, Viral, Animal / Q000276:immunology* / Q000821:virology; D052678:Hepevirus / Q000276:immunology*; D006801:Humans; D016056:Immunodominant Epitopes / Q000737:chemistry / Q000276:immunology; D011201:Poultry Diseases / Q000276:immunology* / Q000821:virology; D012327:RNA Virus Infections / Q000276:immunology / Q000662:veterinary* / Q000821:virology
D000956:Antigens, Viral; D036022:Capsid Proteins; D016056:Immunodominant Epitopes
Avian HEV; Capsid protein; Epitopes; Immunodiagnostics