PRESENTED BY REKHA

M.SC. THIRD SEMESTER

BBAU LUCKNOW.

EDIBLE VACCINE

WHAT IS EDIBLE VACCINE ?

Edible Vaccine involves introduction of selected desired genes into plant and then

inducing these altered plants to manufacture the altered protein.

These types of vaccines are antigenic proteins that are genetically engineered into aconsumable crop. The strategy is that the plant food product haves the proteinwitch is obtained from some disease causing pathogen. People eat the plant food,the food is digested.

The genes encoding antigens of bacterial and viral pathogens can be expressed

in plants in a form in which they retain native immunogenic properties.

TRANSGENIC PLANTS

Recombinant protein origin plant application

Somatotrophin human tobacco growth hormone

Serum albumin human tobacco burns/fluid replacement

Protein C human tobacco anticoagulant

Hirudin hirudo canola anticoagulant

medicinalis

Lactoferrin human potato antimicrobial

Trichosanthin trichosanthis tobacco HIV therapy/cancer

kirilowii

Homotrimeric collagen human tobacco collagen

Adrian Slater,W.Scott,R.Fowler

Trichosanthin

Trichosanthin is a ribosome-inactivating

protein used in Chinese medicine may be

useful as a treatment for HIV/AIDS.

Relatively high levels of trichosanthin

accumulation in N.benthamiana Using a viral

RNA based transfection system.

GlucocerebrocidaseGaucher disease is an inherited disorder in

which glucocerebroside accumulate in

lysosomes due to deficiency in the

glucocerebrosidase a process to produce

glucocerebrosidase in tobacco.

Human serum albuminHSA,Treatment of burns and

liver cirrhosis HSA expressed in

tobacco and potato under the

control 35S promoter.

Adrian Slater,W.Scott,R.Fowler

TARGET PATHOGENS EXPRESSED IN, MODE OF ADMINESTRATION

Enterotoxigenic Ecoli (humans) Potato, tobacco Immunogenic and protective when

administered orally.

Vibrio cholera(humans) Potato Immunogenic and protective when

administered orally.

Hepatitis B virus

(humans)

Tobacco Extracted proteins is Immunogenic

when administered by injection

Hepatitis B virus

(humans)

Potato Immunogenic and protective when

administered orally.

Norwalk virus(humans) Potato Virus like particles form and

Immunogenic when administered orally.

Rabies virus (humans) Tomato Intact glycoproteins

Foot and mouth disease

(agricultural domestic

animals)

Arabidopsis Immunogenic and protective

when administered orally

Foot and mouth disease

(agricultural domestic

animals)

Alfalfa Immunogenic and protective

when administered by

injection or orally

Transmissible

gastroenteritis corona virus

Maize Protective when administered

oral

Organization Vaccines Current R & D Status

International Centre for Genetic

Engineering &

Biotechnology (ICGEB), New Delhi

Malaria Developed a malaria vaccine (p.

vivox and p falciparum) and

technology has been transferred

recently.

HIV/AIDs vaccine Basic R&D

DengueDeveloping a tetravalent dengue

vaccine candidate

Hepatitis E (VLP vaccine) R&D

HIV/AIDS (Recombinant vaccine) Phase-I, II clinical trial

National Institute of Immunology

(NII), New Delhi

Tuberculosis (TB) Developing r-DNA based vaccine

candidate molecule

Human Papilloma virus (HPV)Developing vaccine candidates

against HPV

: Vaccine R&D profile in India

ICGEB

NII

Vaccine and R&D map of India

William, 2000

Ling et al., 2010

ENTEROTOXIGENIC ESCHERICHIA COLI (ETEC)

ETEC is attached to specific receptors on the surface of enterocytes in the intestinal lumen by

fimbriae.

ETEC produces a heat-stable enterotoxin (ST) which consists of five B subunits and one A subunit.

B subunit binds to sugar residues of ganglioside Gm1 on the cells lining the villi of the small

intestine.

Insertion of the B subunit into the host cell membrane forms a hydrophilic transmembrane channel

through which the toxic A subunit can pass into the cytoplasm (Roy et al., 2010).

Raw transgenic potato expressing LT-B were fed to 11 volunteers, out of which 10(91%) developed

neutralizing antibodies and 6(55%) of individuals also showed mucosal response (Tacket et al.,

1998).

Synthetic heat-labile enterotoxin (LT-B) gene and their expression in plants such as potato, banana,

tobacco and tomato; and all were tested in mice (Mason et al., 1998).

VIBRIO CHOLERA

Enterotoxin heat-labile (LT) similar as cholera toxin (CT) was expressed in potato plant (Arakawa et

al., 1998). Nochi et al. (2007), showed oral immunization with transgenic rice encoding the cholera

toxin B subunit (CTB) which stimulates secretory Ig A, shows resistant to gastrointestinal digestion.

Karaman et al. (2012) introduced synthetic gene encoding for CT-B by the control of a γ-zein

promoter in maize seeds.

CT-B levels were checked via ganglioside dependent ELISA. AntiCTB IgG and anti-CTB IgA

were found in the sera and fecal samples of the orally immunized mice protected against holotoxin

challenge with CT

( Kumar1 et al, 23 July, 2013 )

Transgenic potato with CT-B gene of Vibrio cholerae was shown to be effective in mice.

Eating one potato a week for a month with periodic boosters was said to

provide immunity.

NORWALK VIRUS

Norwalk viruses are a major cause of food and water associated outbreaks of diarrhoea andvomiting, affecting individuals of all age groups.

A capsid protein of Norwalk virus was expressed in transgenic tobacco and potato plants. Potatotubers expressing Norwalk virus antigen were fed to mice, it developed serum IgG specificfor Norwalk virus (mason et al., 1996). According to tacket et al. (2000) volunteers fed withtransgenic potato expressing Norwalk virus antigen showed seroconversion ( kumar1 et al, 23 july,2013 )

Nineteen (95%) out of 20 people fed with

transgenic potato expressing

Norwalk virus antigen showed seroconversion .

Attempts are underway to engineer

bananas and powdered tomatoes

expressing Norwalk virus.

HEPATITIS B VIRUS

• HBs Ag was expressed in transgenic potato plant and tested in mice for production of

antibodies (Richter et al., 2000) pniewski et al. (2011) has shown the production of small

surface antigen for HBV (S-HBsAg) in genetically modified glufosinate-resistant lettuce.

• They orally immunised mice by using lyophilised form of plant material and showed the presence

of secretory IgA (S-IgA) and total serum antibodies. Li et al. (2011) also demonstrated the

transformation of HBsAg (hepatitis B surface antigen) gene in to tomato mediated by

Agrobacterium tumifaciens ( Kumar1 et al, 23 July, 2013 ).

• The amount of HBsAg needed for one dose could be achieved in a single potato.

When cloned into CaMv , plasmid HBsAg

subtype showed higher expression in roots

as compared to leaf tissue of the transgenic

potato.

MEASLES

Measles antigens expressed in plants oral immunization with plant based

measles virus haemagglutinin protein (Pickering et al., 2006).

Webster et al. (2002) confirmed that the transgenic tobacco plants-derived

MV-H protein vaccine, which when, modified to MV-H DNA vaccine, to prime-

boost vaccination strategy demonstrated the MV hemagglutinin protein(MV-H)

expression. Orally immunized mice with plant derived MV-H showed MV-

specific IgG.

Transgenic rice, lettuce and

baby food against measles are

also being developed. ( Kumar1 et al, 23 July, 2013 )

MECHANISM OF ACTION

The goal of oral vaccination is to stimulate the mucosal and systemic

immunity against pathogen.

Edible vaccine when taken orally undergoes the mastication process

and the majority of plant cell degradation occur in the intestine.

The breakdown of edible vaccine near PP , consisting of the

30-40 lymphoid nodules on the outer surface of intestine and

contain follicles.

.

These follicles act as the site from which antigen penetrates the intestinal

epithelium ,thereby accumulating antigen within organized lymphoid

structure .

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.

ADVANTAGE OF EDIBLE VACCINE

Edible means of administration.

Reduced need for medical personnel and sterile injection conditions.

Storage near the site of use.

Possible production of vaccines with low costs.

Economical in mass production and transportation.

Easy for separation and purification of vaccines from plant materials.

Heat stable, eliminating the need for refrigeration.

Antigen protection through bio encapsulation.

Enhanced compliance (especially in children).

Effective prevention of pathogenic contamination from animal cells.

DISADVANTAGE OF EDIBLE VACCINE

Development of immunotolerance to vaccine peptide or protein.

Consistency of dosage form fruit to fruit, plant-to-plant, and generation-to-

generation is not similar.

Stability of vaccine in fruit is not known.

Dosage of vaccines would be variable.

Selection of best plant is difficult.

Certain foods like potato are not eaten raw, and cooking the food might weakens the

medicine present in it.

Not convenient for infants.

References

3)P Lal et al, edible vaccines: current status and future, Indian journal of medical microbiology, (2007) 25

(2):93-102.

9)Mason HS, et al. (2002). Edible plant vaccines: applications for prophylactic and therapeutic molecular

medicine. Trends Mol. Med. 8:324-329.

10) Ruf S, et al. (2001). Stable genetic transformation of tomato plastids and expression of a foreign protein in

fruit. Nat. Biotechnol. 19:870-875.

11) Ongoing Project- Development of edible vaccine using transgenic plants (HIV antigen into Tomatoes)

funded by Agriculture research service of the U.S department of Agriculture which is ISTC partner project

#2176 http://www.istc.ru

12) Mason H. S. et al. (1992). Expression of Hepatitis B surface antigen in transgenic plants, Proct Natl Acad

Sci USA, pp- 11745-11749

13) Mason H. S. et al. (1996). Expression of Norwalk virus capsid protein in transgenic potato and tomato plants

and its oral immunogenicity in mice, Proct Natl Acad Sci USA, pp- 5335-5340

14) Yusibev V. et al.(2002) Expression implants and immunogenicity of plant virus based experimental rabies

vaccine, vaccine, 20, pp-3155-3164

THANK

YOU