Development of a Plant-based Vaccine aganist HIV

DESCRIPTION (provided by applicant): Plant-based vaccines have now been proven to impart resistance to various viral and bacterial diseases in animals and in humans. These vaccines can be produced in a transgenic plant product such as corn flour. When ingested, the protein subunit induces a mucosal immune response. At the same time, some of the protein epitope induces a serum immune response. Plant-based vaccines, produces in grain, have several advantages including not needing a cold chain or needles. Any HIV immunogens will have excellent stability within the dry corn seed matrix allowing accurate dosing. Extremely inexpensive to produce, plant-based vaccines in corn seed make the ideal delivery system for protein subunit vaccines in areas of the world where a reliable cold chain, needle disposal and top quality medical personnel are issues of great importance. One plant-based vaccine has recently been shown to induce high antibody titers in the colostrums of postpartum female animals. Titers induced by the plant-based vaccine in corn was several-fold higher than using an existing injectable commercial vaccine. Thus, an HIV plant-based vaccine may have promise in controlling HIV transmission from an infected mother to infant through breast milk. We propose to put genes encoding three different HIV immunogens into individual corn lines. Seed material containing each HIV protein would be produced and analyzed for protein expression. High expressing lines will be selected for further development. Animal feeding studies would be conducted during a Phase II grant. Several new HIV gp120-related immunogens have been developed recently and these would make ideal candidates for an edible vaccine. We propose testing a gp120 subtype B strain, a gp140 version of that same strain, and a consensus env sequence recently published by Gaschen et al. (2002, Science 296:2354).