SINGLE-INJECTION, SELF-CONTAINED BOOSTER VACCINE

Vaccination is a particularly powerful weapon in the fight against wide-spread livestock disease. Commercially available vaccines, however, are often difficult and costly for livestock producers to use properly, leaving individual animals - and by extension the global food supply - at risk. More specifically, many vaccines on the market today require multiple injections spaced several weeks apart (i.e. primer dose; two (or more) week delay period; booster dose) to achieve a protective level of immunity in the host animal. These booster doses are often not administered for a variety of reasons, including: (1) the cost and logistical difficulty of rounding up livestock that graze over large areas of land and (2) the nature of the livestock supply chain (e.g. the animal receives the primer does, but is sold to a finishing lot before the booster dose is administered). Taken together, there is a critical need for new livestock vaccines that eliminate the necessity for booster injections.

Specific Aim 1: Perform in vitro release profile testing to screen potential delayed-burst microcapsule architectures and identify two lead formulations for use in in vivo testing. We will use Orbis's PPF technology to create microcapsules comprised of H1N1 swine influenza vaccine (antigen plus aluminum hydroxide adjuvant) cores and polymer shells. We will test the effect of shell material type and shell thicknesses on release. We will also characterize the in vitro release performance of each formulation to identify two formulations that have the greatest chance of eliciting the desired immunologic response in vivo. Critical success criterion will be the identification of a minimum of one formulation that is capable providing for an in vitro release profile characterized by two week delayed release (no more than 5% release) followed by a distinct pulse (80% release within 48 hours) release of the microencapsulated vaccine. Specific Aim 2: Characterize the ability of the delayed-burst microcapsules to achieve an immunological response in a porcine model. We will test the ability of our delayed-pulse, self-contained booster vaccines to elicit an adaptive immune response in a porcine model. H1N1-free swine will be subcutaneously injected with the two lead formulations - developed during Specific Aim 1 - and compared to the standard vaccination protocol (primer plus booster dose 21 days later). H1N1-specific antibodies titers will be measured and reported to provide direct evidence of the ability of our self-contained booster formulations to impart protective vaccination to the host.