Enhanced Oral Vaccine Delivery Vehicle

DESCRIPTION (provided by applicant): The goal of this research proposal is to develop a potent oral vaccine platform that is reusable for different pathogens and can be manufactured more rapidly and at lower cost than currently available technology. Rapid production time and ease of distribution of a vaccine in tablet form will provide for an effective countermeasure against influenza and other potential pandemic viruses. An effective gene-based technology must overcome the major obstacles of pre-existing and vaccine-induced immunity to the vector if it is to be used as a general platform for multiple antigens or boosting. The oral vaccine route is more likely to effectively circumvent vaccine induced immunity problems that occur with parenteral vector vaccines because long-term mucosal immunity in the intestine is notoriously difficult to achieve. However, the performance of oral vaccine vectors has not matched that of injected vectors. Using West Coast Biological's patent pending technology, preliminary studies in this proposal demonstrate that Toll Receptor 3 ligand, given in conjunction with antigen expressed from a non-replicating adenovirus vector significantly augments the adaptive immune response to oral vaccination. The proposed Aims test two forms of the adjuvant: an exogenously added TLR3 ligand and expressed double stranded RNA ligands encoded by the recombinant adenoviral vector. Aim 1 of this proposal strives to generate oral vaccine performance equal to or better than that of muscle injected recombinant adenovirus by optimizing the relative amounts of exogenously added TLR3 ligand and recombinant adenovirus. Aim 2 affirms selection of an expressed version of TLR-3 ligand by evaluating the ability of the expressed ligands to mature primary dendritic cell cultures and induce pro-inflammatory cytokines. Aim 3 investigates the in vivo performance of the expressed TLR3 ligand constructs with recombinant adenovirus and compares this to use of exogenous TLR3 ligand with recombinant adenovirus for induction of antibody responses and CTL responses. Aim 4 tests the ability of our oral vaccine vector to be reused without loss of activity by assessing vaccine efficacy following induction of substantial anti-vector neutralizing titers in plasma, and by examining the duration of the mucosal immune response following oral vaccination. For all of these aims, we will measure antibody and T-cell responses in mice using ELISA and tetramer based assays. Together, these aims will map the development plan to commercialize the oral vaccine vector technology.