Oral Vaccination Against Anthrax Using a Transgenic Plant Expressing Protective Antigen

Vaccines have significantly improved the health of animals and humans during the past century. However, there are still problems associated with cost, distribution and safety in administration of the vaccines, e.g., needle-stick injuries. Anthrax caused by Bacillus anthracis is a world-wide problem affecting both animals and humans. Although current anthrax vaccines for humans and animals have proven effective, recurring problems related to safety, cost, and drug delivery suggest the need for new approaches. The goal of this proposal is to develop transgenic plants for the production of oral (food-based) delivery of a new recombinant vaccine based on isolated DNA sequences coding for the highly immunogenic B. Anthracis protective antigen (PA). Specific objectives of Phase I are to 1) generate plant transformation/expression vectors encoding PA and a fusion protein of PA and CTB (the B subunit of cholera toxin which would facilitate PA transfer across o he gut mucosa), 2) introduce the PA and PA:CTB antigen genes into tobacco via Agrobacterium-mediated transformation, and 3) affinity-purify PA protein from transgenic tobacco tissue and assess its immunogenicity. Successful conclusion of Phase I objectives will provide a strong basis for scaled up recombinant vaccine production and testing planned for Phase II.