An Overview on Edible Vaccines and Immunization

Review Article

Austin J Nutri Food Sci. 2016; 4(2): 1078.

An Overview on Edible Vaccines and Immunization

Naeema Jan¹, Fouzia Shafi¹, Omar bin Hameed¹, Khalid Muzaffar², Shuaib Mohammad Dar², Ishrat Majid² and Nayik GA²*

¹Division of Post Harvest Technology, SKUAST-Kashmir, India

²Department of Food Engineering & Technology, SLIET, Punjab, India

*Corresponding author: Nayik GA, Department of Food Engineering & Technology, SLIET, Punjab, India

Received: March 03, 2016; Accepted: June 01, 2016; Published: June 07, 2016


Edible vaccines offer cost-effective, easily administrable, storable and widely acceptable as bio friendly particularly in developing countries. Oral administration of edible vaccines proves to be promising agents for reducing the incidence of various diseases like hepatitis and diarrhea especially in the developing world, which face the problem of storing and administering vaccines. Edible vaccines are obtained by incorporating a particular gene of interest into the plant, which produces the desirable encoded protein. Edible vaccines are specific to provide mucosal activity along with systemic immunity. Various foods that are used as alternative agents for injectable vaccines include cereals (wheat, rice, corn) fruits (bananas) and vegetables (lettuce, potatoes, tomatoes). Thus, edible vaccines overcome all the problems associated with traditional vaccines and prove to be best substitutes to traditional vaccines.

Keywords: Edible vaccines; Transgenic plant; Traditional vaccines


Vaccines have proved to be boon for the prevention of infectious diseases. In spite of the global immunization programme for children against the six devastating diseases, 20% of infants still remain unimmunized which lead to approximately two million unnecessary deaths per annum, particularly in the far flung and poor parts of the world [1]. This is because of the limitations on vaccine production, distribution and delivery. This problem needs to resolve in order to prevent the spread of infections and epidemics by un-immunized populations in the immunized, safe areas [2]. Immunization for certain infectious diseases, either do not exist or they are unreliable or very expensive like; immunization via DNA vaccines is substitute but is an expensive method, along with some undesirable immune responses. Besides being expensive, these vaccines pose the problem of storage and transportation, as many of them require refrigeration. Hence, there is search for easily administrable, storable, fail-safe and widely acceptable bio friendly vaccines and their delivery systems especially in developing countries. Therefore, as substitutes have to be produced for traditional vaccines, it was envisaged that plants could be promising agents for efficient production system for vaccines, which in turn gave rise to the novel concept of edible vaccines.

Concept of Edible Vaccines

Development of edible vaccines involves the process of incorporating the selected desired genes into plants and then enabling these altered plants to produce the encoded proteins. This process is known as transformation, and the altered plants are known as transgenic plants. Edible vaccines like traditional subunit vaccines consist of antigenic proteins and are devoid of pathogenic genes. Despite this advantage, traditional subunit vaccines are unaffordable and technology-intensive, require purification, refrigeration and produce poor mucosal response. Unlikely, edible vaccines would eliminate the need for trained medical personnel required for oral administration particularly in children. Production of edible vaccines is effective process and can be easily scaled up. Edible vaccines offer numerous advantages like they posses good genetic and heat stability and do not need cold-chain maintenance. Edible vaccines can be stored at the site of use thus avoiding long-distance transportation. Syringes and needles are also not required, thus reduces the incidence of various infections [3]. Important advantage of edible vaccines is elimination of contamination with animal viruses-like the mad cow disease, which is a hazard in vaccines developed from cultured mammalian cells, as plant viruses cannot infect humans. Edible vaccines act by stimulating the mucosal as well as systemic immunity, as soon they meet the digestive tract lining. This dual mechanism of action of edible vaccines provide first-line defense against pathogens attacking via mucosa, like Mycobacterium tuberculosis and carriers causing diarrhea, pneumonia, STDs, HIV etc. [1]. Oral administration of edible vaccines to mothers might prove to be useful in immunizing the fetus-in-utero by transplacental movement of maternal antibodies or the infant through breast-feeding. Edible vaccines enable the process of seroconversion in the presence of maternal antibodies, thus playing a possible role in protecting children against diseases like group-B Streptococcus, respiratory syncytial virus (RSV), etc. At present edible vaccines are produced for various human and animal diseases (measles, cholera, foot and mouth disease and hepatitis B, C and E). They can also be used to prevent exceptional diseases like dengue, hookworm, rabies, etc. by combining with other vaccination programmes enabling multiple antigen delivery. Various foods under investigation for use in edible vaccines include banana, potato, tomato, lettuce, rice, etc. [4].

Developing an Edible Vaccine

The selected gene obtained from the microbes encoding specific antigen can be handled in two different ways:

Agrobacterium mediated gene transfer

In this method, the suitable gene (recombinant DNA) is incorporated into the T-region of a disarmed Ti plasmid of Agrobacterium; a plant pathogen, which is co-cultured with the plant cells, or tissues that needs to be transformed (Figure 1). This approach is slow with lower yield however; it showed satisfactory results in dicotelydenous plants like potato, tomato and tobacco. Researches in some fields have proven this approach good in expressing the desirable traits by selected genes in several experimental animals and plants [5,6].

Citation: Jan N, Shafi F, bin Hameed O, Muzaffar K, Dar SM, Majid I, et al. An Overview on Edible Vaccines and Immunization. Austin J Nutri Food Sci. 2016; 4(2): 1078.