Expression and serological application of recombinant epitope-repeat protein carrying an immunodominant epitope of Newcastle disease virus nucleoprotein

Gaikwad, Satish S.; Lee, Hyun-Jeong; Kim, Ji-Ye; Choi, Kang-Seuk

Marker NDV vaccines in conjugation with serological diagnostic test has substantial value in poultry industry for demonstration of the freedom of ND. A serologic marker antigen is a viral protein or an epitope that is absent from the vaccine strains but consistently present in the corresponding wildtype viruses [5] . Therefore, only animals that have been infected with wild-type virus will develop antibodies against the serologic marker antigen while the vaccinated animals will not. The marker antigen should be conserved and immunodominant to ensure that the companion diagnostic test based on this marker antigen will produce reliable diagnostic results [20] . In addition, the marker antigen should be dispensable for the viral life cycle but should not contribute significantly to the overall immunogenicity of the vaccine. Subunit vaccines using F and HN protein [21] can serve as marker vaccines but are less effective than whole virus vaccines [22] . This necessitates NDV marker vaccine based on chimeric live virus.