GPI-GM-CSF protein transferred onto H5 influenza VLPs remains stably expressed and functionally active (P6168)

Abstract

Abstract Pathogenic H5N1, a lipid-enveloped influenza virus, is a pandemic threat. The use of virus-like particles (VLPs) as an alternative to current influenza vaccines is highly promising. VLPs are similar in structure to their live viral counterparts but do not contain viral genome that is required for replication; hence VLPs provide for a safe and immunogenic vaccine. Although the particulate nature of VLPs allows them to be highly immunogenic, the need for protection against heterotypic viruses still remains. Therefore, inclusion of immunostimulatory molecules (ISMs) onto the VLP surface can help to induce cross-protection against strains and provide for stronger immunity. We were able to show that GPI-anchored-GM-CSF can incorporate stably onto H5 influenza VLP surfaces after a simple and quick protein transfer method. This method allows for the incorporation of the GPI-anchor onto the surface of lipid-bilayered VLPs within a matter of hours and allows for the incorporation of multiple GPI-ISMs in a concentration-dependent manner. Furthermore, protein transferred VLPs were functional in leading to bone marrow derived cell proliferation compared to unmodified VLPs, and incorporated GM-CSF was as functional as equal concentrations of commercially available recombinant soluble GM-CSF. Therefore, VLPs expressing GPI-GM-CSF could lead to enhanced immunogenicity and antiviral immune responses compared to unmodified VLPs.