Display of foreign surface antigens on baculovirus as pseudotyped viruses for immunological studies and applications

Display of foreign surface antigens on baculovirus as pseudotyped viruses for immunological studies and applicationsBaculovirus is an insect virus, and has long been used as a safe microbial agent for high level vaccine production and gene delivery into mammalian cells with high efficiency. Baculovirus has a major surface protein named GP64, which is a trimeric protein that functions for receptor recognition allowing baculovirus to enter the host cells. We found that the domain underneath this protein called cytosolic terminal domain (CTD) is crucial for the anchoring of any membrane protein targeting to the envelope of the baculovirus. By adding the CTD of GP64 to the spike protein of SARS virus, we have successfully anchored this protein onto baculovirus, and this functional pseudovirus allowed us to prove that spike protein is responsible for the induction of cytokine storm, and in turn induces illness of the patients. In further experiments, we found that this technology can be applied to display the surface proteins of influenza viruses. We have fused CTD from GP64 to the C-terminal of hemagglutinin, a trimeric major surface protein of influenza virus, and generated baculovirus-based pseudovirus. This pseudovirus was used to inject mice for antibody production. After three antigen shots, the mouse was sacrificed and analyzed the generated monoclonal antibodies. We found both neutralizing and non-neutralizing antibodies were induced. We also presented the neuraminidase (NA) protein of the flu virus onto the envelope of baculovirus and showed that NA, a tetrameric protein, can be functional on baculovirus for enzymatic assays. Therefore, surface display of foreign proteins on baculovirus with the assists of GP64 CTD is a useful technology to apply or study those major surface antigens of detrimental viruses