Membrane-Bound Immunomodulators As Adjuvants In A Cell Culture-Based Avian Influenza Vaccine

MEMBRANE-BOUND IMMUNOMODULATORS AS ADJUVANTS IN A CELLCULTURE-BASED AVIAN INFLUENZA VACCINEbyDAVID D. FISCHERDecember 2012Advisor: Dr. Roy SundickMajor: Immunology & MicrobiologyDegree: Doctor of PhilosophyInactivated viral vaccines often generate suboptimal immune responses. Adjuvants areincorporated into vaccines to increase their immunogenicity, however currently availableadjuvants have shortcomings which have limited their use in human and veterinary medicine.This necessitates the development of new adjuvants and delivery systems. Cytokines have beenextensively tested as adjuvants in vaccines but challenges such as diffusion from antigen, shorthalf-lives and production costs have been encountered. To address this, we developed atechnology that efficiently produces inactivated, whole-virus influenza vaccine bearingmembrane-bound cytokines. Tethering the cytokine to the antigen of interest keeps theimmunomodulator in close contact with the antigen ensuring that immune cells recruited oractivated by the adjuvant react with the antigen as well. Influenza can be used to test this modelsince its surface proteins HA and NA contain conserved signal sequences that direct theseproteins to the infected cell surface where they are picked up by budding virions. Plasmidscontaining cytokines fused to these signal sequences are transfected into MDCK cell lines and,upon expression, the fusion proteins are directed to the lipid islands on the cell membrane.When the cells are infected with influenza, new virus assembles at the lipid islands andincorporates the fusion proteins into the viral envelope. Furthermore, this in vitro cell culture-