Protective immunity elicited by a pseudotyped baculovirus-mediated bivalent H5N1 influenza vaccine.

The development of novel H5N1 influenza vaccines to elicit a broad immune response is a priority in veterinary and human public health. In this report, a baculovirus vector was used to construct bivalent recombinant baculovirus vaccine encoding H5N1 influenza virus hemagglutinin proteins (BV-HAs) from clade 2.3.4 and clade 9 influenza viruses. Mice immunized with 5×10(7) IFU BV-HAs developed significantly high levels of H5-specific neutralizing antibodies and cellular immunity that conferred 100% protection against infection with H5N1 influenza viruses. This study suggests that baculovirus-delivered multi-hemagglutinin proteins might serve as a candidate vaccine for the prevention of pre-pandemic and pandemic H5N1 influenza viruses.