Plant vaccines

EDILE VACCINES; Plant based vaccines.

1. Plant expression system based vaccines BY NIKUNJ TYAGI 17-P-BT-06

2. PLANT BASED VACCINES/EDIBLE VACCINES Barta and colleagues were the first to transcribe a chimeric gene of nopaline synthase and human growth hormone in sunflower and tobacco plants using the Ti plasmid [Barta et al .1986 ] Definition: Plant expression system based vaccines are nothing but transgenic plant based production of or those that contain agents that trigger an animal’s immune response. These vaccines contain DNA fragments from the original pathogen. These fragments code for a protein that is usually a surface protein of the pathogen. This is responsible for eliciting the body’s immune response TOMATO PLANTS AND BANANA TREES growing at the Boyce Thompson Institute for Plant Research at Cornell University have been genetically engineered to produce vaccines in their fruit

3. Needle free Oral vaccines provide “mucosal immunity” at various sites by secreting antibodies. Do n ‟ t need t o w orry a bout r e - use, m is u se a n d l a c k of sterilization. Thus, low risk of infection. Cheap Estimated cost of $0.005 to grow antigen for one dose of hepatitis B vaccine in an unprocessed form . A d m i ni s t e r i n g o r al v ac c in e s woul d r eq u i r e l i t t l e o r no training at all.

4. s t o r a g e s a f e Most importantly, they trigger the immunity at the mucosal surfaces such as mouth which is the body’s first line of defense. Needs no purification . Edible vaccine activates both mucosal and systemic immunity Heat-stable; do not require cold-chain maintenance. If the local/native crop of a particular area is engineered to produce the vaccine, then the need for transportation and distribution can be eliminated.

5. Two ways …… In one case , the entire structural gene is inserted into plant transformation vector between 5‟ and 3‟ regulatory element ; this will allow the transcription and accumulation of encoding sequence in the plant. In the second case , epitope within the antigen are identified ,DNA fragment encoding these can be used to construct gene by fusion with a coat protein gene from plant virus e.g. TMV or CMV . D eveloping an Edible vaccine

6. Producing of edible vaccine antigen in plant tissue Mishra et al,2008

7. Methods for transformation of DNA/gene into plant Plasmid vector carrier system : Agrobacterium tumefaciens method. Micro projectile bombardment method. Electroporation method

8. Mechanism of Agrobacterium-mediated transformation in plants Shweta Mehrotra, Appl Biochem Biotechnol (2012)

9. Mechanism of Action Edible vaccine when taken orally undergoes the mastication process and the majority of plant cell degradation occur in the intestine as a result of action of digestive or bacterial enzyme on edible vaccine The breakdown of edible vaccine near PP , consisting of the 30-40 lymphoid nodules on the outer surface of intestine and contain follicles The antigen then comes in contact with M-cell . M cell passes the antigen to macrophages and B cell. These B cell activates the T cell to provide immune response In this way the immunity is activated by the edible vaccine .

10. Fig. Structure of gut MIS

11. SCIENTIFIC AMERICAN REPORTS,2006

12. Ling et al ., 2010

13. Newcastle disease NDV is highly infectious, affecting domestic poultry and wild birds. NDV transmission occurs through direct contact with secretions or discharge of infected birds, and contact with fomites. The world's first regulatory approval for a PMV was against NDV. The HN protein from NDV was expressed in a tobacco cell system and found to retain the size and immunoreactivity Lin et al 2010

14. Foot-and-mouth disease Foot-and-mouth disease (FMD) is one of the most contagious viral diseases of wild ruminant and domestic animals. The causative pathogen, FMD virus (FMDV). FMDV is a single-stranded, positive-sense RNA virus, possessing four capsid proteins VP1 , VP2 , VP3 and VP4 . The VP1 protein is the critical determinant for vaccination against FMD with the induction of VP1-neutralizing antibodies required for immunity. Studies have shown the potential of using VP1 capsid protein as a subunit PMV candidate, in potato, tobacco, and tomato . Lin et al 2010

15. N Takeyama, K Hiroshi et al,2015

16. N Takeyama, K Hiroshi et al,2015

17. N Takeyama, K Hiroshi et al,2015

18. Limitations Dosage required varies from generation to generation and, plant to plant, protein content, patient age , weight, ripeness of the fruit and quantity of the food eaten . Edible vaccine administration requires methods for standardization of plant material/product as low doses may produce lesser number of antibodies and high doses are responsible immune tolerance . Edible vaccines are dependent on plant stability as certain foods cannot be eaten raw (e.g. potato) and needs cooking that cause denaturation or weaken the protein present in it Edible vaccines are prone to get microbial infestation e.g. potatoes containing vaccine can last long if stored at 4°C while a tomato cannot last long . Proper demarcation line is necessary y between ‘vaccine fruit’ and ‘normal fruit’ to avoid misadministration of vaccine, which can lead to vaccine tolerance. Edible vaccine function can be hampered due to vast differences in the glycosylation pattern of plants and humans .

19. FUTURE Edible vaccine holds a great potential . It reduces the cost of transportation and refrigeration. It neglect the needle and complicated way of vaccine administration. Resistance towards GM foods presents a threat to the rising future of edible vaccines. Transgenic contamination is also a major concern which need to be addressed properly A final issue worth studying is whether food vaccines ingested by mothers can indirectly vaccinate their babies

20. PARENTERAL VACCINE EDIBLE VACCINE

21. References Edible Vaccines By William H. R. Langridge, SCIENTIFIC AMERICAN REPORTS, DECEMBER 2006 Plant-based vaccines for animals and humans: recent advances in technology and clinical trials by Natsumi Takeyama, Hiroshi Kiyono and Yoshikazu Yuk, Ther Adv Vaccines 2015 , Vol. 3(5-6) 139–154 Agrobacterium-Mediated Gene Transfer in Plants and Biosafety Considerations by Shweta Mehrotra & Vinod Goyal, Appl Biochem Biotechnol (2012 ) Current status of plant made vaccines for veterinary purposes. Ling H-Y , Pelosi A, Walmsley AM (2010) Expert Rev Vaccines 9 ,971–982 .

22. Takeyama et al ,2015