Surface Display of Avian Influenza Virus Hemagglutinin on Baculovirus Envelope: Effects of Cytoplasmic Domain on Virus Properties

• Main Authors: Yang, Ding-Gang, 楊定罡
• Other Authors: Lai, Yiu-Kay
• Format: Others
• Language: en_US
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/36452494989643758299

碩士 === 國立清華大學 === 生物科技研究所 === 94 === Hemagglutinin (HA) is the major immunogen on the envelope of avian influenza virus (AIV). To examine how the choice of cytoplasmic tail domain (CTD) affected the display of HA on baculoviral envelope and baculovirus properties, and evaluate the feasibility of HA-pseudotyped baculovirus as a vaccine against AIV infection, we constructed two pseudotyped baculoviruses: Bac-HA expressing chimeric HA with the CTD derived from HA, and Bac-HA64 expressing chimeric HA with the CTD derived from baculovirus envelope protein gp64. After infection with Bac-HA or Bac-HA64, HA with either CTD was anchored on the plasma membrane of Sf9 cells as revealed by confocal microscopy. Immunogold electron microscopy demonstrated that both Bac-HA and Bac-HA64 displayed HA on the viral surface. However, SDS-PAGE and Western blot analyses of purified viruses unraveled that a significantly higher amount of HA was incorporated into Bac-HA64 than into Bac-HA. In comparison with Bac-HA, Bac-HA64 significantly improved the gene delivery and transgene expression in mammalian cells as determined by quantitative real-time PCR and flow cytometry. Immunization of BALB/c mice with Bac-HA64 elicited significantly higher hemagglutination inhibition titers than Bac-HA and the negative controls. These data collectively confirmed that gp64 CTD, in comparison with HA CTD, endowed more efficient HA incorporation into baculovirus, more efficient transgene delivery and expression, as well as elevated immunogenicity. In conclusion, this is the first report demonstrating that the choice of CTD has a tremendous impact on baculovirus property and vaccine efficacy. The baculovirus-based vaccine may hold great promise as a novel platform to prevent avian flu epidemic and be envisaged as an alternative option in the priming-boosting vaccination scheme.