Expression of hemagglutinin-neuraminidase protein of Newcastle disease virus in transgenic tobacco

Abstract

Newcastle disease is one of the most important pathogens of domestic poultry including chickens. The hemagglutinin-neuraminidase (HN) of Newcastle disease virus is the principal target of neutralizing and protective antibodies against Newcastle disease. In this paper, we transformed tobacco plants with Agrobacterium tumefaciens EHA105 to generate the plants expressing HN of Newcastle disease virus (NDV). The insertion and copy numbers of HN gene in the genomic DNA of phosphinothricin-resistant plants were confirmed by PCR and Southern blot, respectively. The presence of the HN-specific transcript in the total RNAs of the leaves of transgenic plants was verified by Northern analysis. The recombinant HN proteins were detected by Western blot analysis using a polyclonal antibody against GST–HN fusion proteins. The highest level of expression of HN in leaves of transgenic plants was approximately 0.069% of the total soluble protein. ELISA assay showed that the recombinant protein extracted from transformants has normal immunoactivity. Transgenic tobacco expressing HN of NDV with sterilized PBS was fed to 6-week-old chickens. Immunized chickens developed slightly high titers of anti-HN serum IgG compared with those of the wild type plant. These results suggest that oral immunization with HN-transgenic tobacco provides a potential means of protecting chickens from NDV. Further modified animal experiments would be needed to increase the immunity of HN by co-administration of classical adjuvants or other trials.