Vaccines are tools in intervention programs for health for humans and animals. They become more widely used - especially in developing countries - if their cost of production could be reduced and whether they could be distributed without refrigeration. Current research is dedicated to solving these limitations by finding ways to produce oral (edible) vaccines in transgenic plants.
Virus hepatitis B (HBV) infection is probably the most important cause of persistent viremia in humans. The disease is characterized by acute and chronic hepatitis, which can also engage in a hepatocellular carcinoma. The prevalence of this disease in developing countries justified initial efforts to express HBV vaccine candidates in plants.
Currently, two forms of hepatitis B vaccines are available, which are both injectable and costly: a purified serum of infected persons and other recombinant antigen expressed and purified yeast. We have transformed plants with the gene coding for hepatitis B surface antigen (HBsAg), which is the same antigen used in the yeast-derived vaccine. An antigenic spherical particles was recovered from these plants, which is similar to the recombinant hepatitis surface antigen (rHBsAg) derived from yeast. Parenteral immunization of mice with plant-derived material has demonstrated that he retains both B and T-cell epitopes, compared with the commercial vaccine.
The selection of a plant delivery system of edible vaccines for humans has been addressed. Recognizing the need to express the desired protein in a food that is consumed raw (to avoid distortion of the candidate vaccine proteins), a system to transform banana plants has been developed. The bananas are produced in most developing countries, and are fed uncooked for infants and adults. The expression of candidate vaccines in fruits bananas will depend identification of specific tissues promoters drive the desired gene expression. The search to find these elements of gene regulation is underway.
Research on edible vaccines is currently directed to human diseases, with special emphasis on the developing world. The technology will also have immediate value for vaccine production inexpensive as additives in feed for farm animals. Since various plant tissues in animal feed, other plants like alfalfa, corn and wheat could be useful to provide vaccines vehicles (and perhaps other pharmaceuticals) to improve Animal Health.
More abstracts about the Edible Vaccine