Evaluation of novel synthetic peptides of avian hepatitis E virus ORF2 as vaccine candidate in chickens.

Avian hepatitis E virus (HEV) has resulted in significant economic losses in the poultry industry. There is currently no commercial vaccination available to prevent avian HEV infection. Previously, a novel epitope (⁶⁰¹TFPS⁶⁰⁴) was discovered in the ORF2 protein of avian HEV. In this study, peptides were synthesized and assessed for their ability to provide immunoprotecting against avian HEV infection in poultry. Twenty-five Hy-Line Variety Brown laying hens were randomly divided into five groups; groups 1 to 3 respectively immunized with RLLDRLSRTFPS, PETRRLLDRLSR (irrelevant peptide control), or truncated avian HEV ORF2 protein (aa 339-606), while group 4 (negative control) was mock-immunized with PBS and group 5 (normal control) was not immunized or challenged. After the challenge, all hens in groups 2 and 4 showed seroconversion, fecal virus shedding, viremia, alanine aminotransferase (ALT) level increasing, liver lesions and HEV antigen in the liver. There were no pathogenic effects in other groups. Collectively, all of these findings showed that hens were completely protected against avian HEV infection when they were immunized with the peptide containing TFPS of the avian HEV ORF2 protein.