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EDIBLE VACCINES Guru Nanak Institute Of Pharmaceutical Science & Technology 157/F, Nilgunj Road, Panihati, Kolakata- 700114 Author- Anurag Chanda 1.Introduction 1,2 - Plants offer enormous potential as production platform for vaccines. Stable integration of a gene into the plant nuclear or chloroplast genome can transform plants like tobacco, potato, tomato, and banana into bioreactors for the production of subunit vaccines. These plant derived vaccines present an alternative to conventional vaccines by facilitating safe and effective oral delivery through the consumption of edible plant tissue. Owing to its low cost, it would suitable for developing countries like India. Today’s development of novel vaccines stresses the need for edible vaccines that are inexpensive and easily administered. 3.Plant species 2,3 - To date many plant species have been used for vaccine production. Early studies used tobacco, potato but now tomato, banana, corn, lupine, lettuce and others are being used for this purpose. The choice of plant species (and tissue in which the protein accumulates) is important and is usually determined how the vaccine is to be determined in the future. For example an edible palatable plant is necessary if the vaccine is planned for raw consumption. 5.A unique opportunity against the threat of bio- weapons 4,5 - •A number of infectious diseases, including smallpox, anthrax and plague have recently raised concern for their possible use in actions of bio- terrorism. •Nations at risk are now faced with the need to be ready to vaccinate part or all of their population within limited periods of time. •This means that millions of vaccine doses have to be prepared, stored and renewed at intervals of time. •The economic and technical benefits offered by plant-derived vaccines propose these vaccines as ideal substitutes for traditional vaccines. •Research on plants that produce antigens against major pathogens feared in case of bio-terrorism is already under way. 6.Dosage 7 - •To explain the concept of oral therapeutic protein delivery, hepatitis B surface antigen (HBsAg) was used for oral immunisation. •No primary immune response was detected after two 300μg doses of yeast derived HBsAg. •However a primary response began after two servings of transgenic potatoes containing, 85-300μg of HBsAg. 7.Side effects 4 - • A research conducted by National Institute of Allergy & Infectious Diseases (NIAID), National Institutes of Health (NIH) and University of Maryland School Of Medicine on human volunteers showed no significant side effects. 8.Limitations 5,6 - •Development of immune tolerance to vaccine peptide or protein. •Consistency of dosage form fruit to fruit, plant to plant, and from generation to generation is not similar. •Stability of vaccine in fruit is not known. •Selection of best plant is difficult. •Certain foods like potato are not eaten raw, and cooking the food might weaken the medicine present in it. References- [1.] William H. R. Langridge. Edible Vaccines. Scientific American (2000). Page 66-71 [2.] Neeraj Mishra, Prem N Gupta, Kapil Khatri, Amit K Goyal, Suresh P Vyas. Edible Vaccines: A new approach to oral immunization. Indian Journal of Biotechnology. Vol 7 (2008). Page 283-294. [3.]Francesco Sala, M. Manuela Rigano, Alessandra Barbante, Barbara Basso, Amanda M. Walmsley, Stefano Castiglione. Vaccine antigen production in transgenic plants: Strategies, gene constructs and perspectives. Vaccine. Vol 21 (2003). Page 803-808. [4.]Mahendra G. Pawar, Komal R. Nikam, Mr.Rakesh D.Amrutkar. Edible Vaccines: A great boon in medicinal science. Pharma Tutor. Vol 2 (2006). Page 34-41 [5.]Ian Auch, Kevin M. Smith. Incredible Edible Vaccines.Boyce Thompson Institute of Staff Research. Vol 58 (2001). Page 90-91 [6.]Kathleen L. Hefferon. Plant-Made Vaccines. Journal of Vaccines and Vaccination. Vol 3 Issue 4. (2012). Page 3-8 [7.]Henry Daniell, Olga Carmona-Sanchez, Britanny E. Burns. Chloroplast derived vaccine antigens. Molecular Farming: Plant made pharmaceuticals and technical proteins. Page 123-124. 4.Oral delivery, mucosal and systemic antibody responses 3,4 - •Plant-derived vaccines have demonstrated the ability to induce both systemic and mucosal immune responses. •The major obstacle to oral vaccination is the digestion of the antigenic protein in the stomach. •Vaccines derived and delivered by plant cells have been shown to overcome this problem through the protective effect of the plant cell wall. 2.Advantages 2 - Potential advantages of plant based vaccines are- •Edible means of administration. •Reduced need for medical personnel and sterile injection conditions. •Economical in mass production and transportation. •Therapeutic proteins are free from pathogens and toxins. •Storage near the site of use. •Heat stable, eliminating the need for cold chain. •Subunit vaccine (not attenuated pathogens) means improved safety. •Delivery of multiple antigens. •Ease of use as raw food or as dry powder.
