| Abstrak/Abstract |
The H5N1 subtype of highly pathogenic avian influenza virus (HPAIV) has been circulating in poultry in Indonesia since 2003 and vaccination has been used as a strategy to eradicate the disease. However, monitoring of vaccinated poultry flocks for H5N1 infection by serological means has been difficult, as vaccine antibodies are not readily distinguishable from those induced by field viruses. Therefore a test that differentiates infected and vaccinated animals (DIVA) would be essential. Currently, no simple and specific DIVA test is available for screening of a large number of vaccinated chickens. Several epitopes on E29 domain of the haemagglutinin H5N1 subunit 2 (HA2), have been recently examined for their antigenicity and potential as possible marker for DIVA in chicken. In this study, the potential of E29 as antigen for DIVA was evaluated in details. Three different forms of full-length E29 peptide, a truncated E29 peptide (E15) and a recombinant E29, were compared for their ability to detect anti E29 antibodies. Preliminary ELISA experiments using mono-specific chicken and rabbit E29 sera, and a mouse monoclonal antibody revealed that the linear E29 peptide was the most antigenic. Further examination of the E29 antigenicity in ELISA using several experimentally infected or vaccinated chicken sera revealed that the full length E29 peptide had the greatest discrimination power between infected and vaccinated chicken sera while provided the least non-specific reaction. This study demonstrates the usefulness of the HPAI H5N1 HA2 E29 epitope as a DIVA antigen in HPAI H5N1 vaccinated and infected chickens. |
