Influenza viruses remains a major health burden due to their abilities to change the epitopes of their major surface glycoprotein hemagglutinin. Although conserved influenza epitopes have been identified, there is a fundamental gap in understanding and correlating the disposition of conserved influenza epitopes on subunit vaccines and designed nanoparticles with immunogenicity. Lack of such information represents important problems and until they are addressed optimal display of conserved influenza epitopes cannot be understood in molecular details. In FY 2019, we characterized the glycoprotein and virion organizations of influenza B viruses and the disposition of viral glycoprotein antigens within commercial influenza subunit vaccines with antigens for typed A and B influenza viruses. Also, we have continued both designing and characterizing various nanoparticles displaying conserved epitopes from influenza antigens, such as hemagglutinin as well as structurally mapping and identifying a novel pan H1 HA epitope within the head region. In addition, we have established significant milestones in the design, purification, 3D structural analysis, and animal efficacy studies of nanoplatforms that have conserved epitopes from both group 1 and group 2 influenza A viruses. These results are significant and relevant to public health because it is expected to expand understanding of the structure and epitope disposition of influenza epitopes on nanoplatforms and HA. This will aid immunogen evaluation and design for more efficacious season vaccines and facilitate the development of universal influenza vaccines.
