No abstract

Hemagglutinin (HA) is the major immunogen on the envelope of avian influenza virus (AIV). Therefore we constructed two recombinant baculoviruses: Bac-HA, expressing histidine-tagged HA with the cytoplasmic domain (CTD) derived from HA, and Bac-HA64, expressing histidine-tagged HA with the CTD derived from baculovirus envelope protein gp64. After infection, HA with either CTD was expressed and anchored on the plasma membrane of Sf-9 cells, as revealed by confocal microscopy. Immunogold electron microscopy demonstrated that both Bac-HA and Bac-HA64 displayed HA on the viral surface. However, analyses of purified viruses revealed that significantly more 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 polymerase chain reaction and flow cytometry. Bac-HA64 elicited significantly higher hemagglutination inhibition titers in mouse models than Bac-HA and the negative controls. These data collectively confirmed that the gp64 CTD, in comparison with HA CTD, resulted in more efficient HA incorporation into baculovirus, more efficient transgene delivery and expression, and elevated immunogenicity. This is the first report demonstrating the potential of HA-pseudotyped baculovirus as an avian influenza vaccine and that the choice of CTD tremendously affects baculovirus properties and vaccine efficacy.

Our data, for the first time, suggest that in insect cells EV71 structural proteins adopt a processing and assembly pathway similar to poliovirus assembly. The preservation of particle morphology and composition suggest that the VLP may be a valuable vaccine candidate to prevent EV71 epidemics.

No abstract

These findings implicate the potential applications of baculovirus as an alternative vector to genetically modify MSCs for ex vivo gene therapy.