TAMIL NADU

University research on plant-based vaccine for Chikungunya

Cost-effective vaccine: R. Satishkumar, Assistant Professor, Department of Biotechnology, Bharathiar University (right) and Varghese P. Inchakalody, a Ph.D. scholar, taking a look at a tobacco plant expressing E1 and E2 proteins, at the plant tissue culture laboratory at the university in Coimbatore. - PHOTO: S. SIVA SARAVANAN

Cost-effective vaccine: R. Satishkumar, Assistant Professor, Department of Biotechnology, Bharathiar University (right) and Varghese P. Inchakalody, a Ph.D. scholar, taking a look at a tobacco plant expressing E1 and E2 proteins, at the plant tissue culture laboratory at the university in Coimbatore. - PHOTO: S. SIVA SARAVANAN  

The Plant Genetic Engineering Laboratory of the Department of Biotechnology in Bharathiar University is into a research on developing a plant-based vaccine against Chikungunya viral infection.

The work, which began in 2007 on “Production of Chikungunya Antigens from Transgenic Tobacco Plants”, has come to the stage of animal trials. At the end of the trials, the proof of concept would be established that the genetically modified tobacco plant, which is being used for the research, is an ideal vaccine candidate.

Proposed by R. Satishkumar, Assistant Professor of the Department, the project is being executed in collaboration with Julian Ma, professor at St. George's, University of London, with support from the UK-India Education and Research Initiative (UKIERI) of the British Council.

“The vaccine that has already been developed for Chikungunya in the United States is based on mammalian cell culture technology. But plants have proved to be cheap and convenient for large-scale production of various therapeutic proteins. They can be used to develop alternatives to the mammalian and bacterial culture,” says Mr. Satishkumar.

The surface of alphavirus that caused Chikungunya is covered by membrane glycoproteins E1 and E2. These are considered as potential vaccine candidates because they have more epitopes (antigenic determinant of the part of an antigen molecule to which an antibody attaches itself) compared to other structural and non-structural proteins.

Realising that tobacco was the ideal candidate for the expression of recombinant proteins, it was identified for the research.

Mr. Sathishkumar, assisted by a Ph.D. scholar of the department, Varghese P. Inchakalody, is involved in producing Chikungunya viral antigens (that induces an immune response in the body) in tobacco for use as a vaccine candidate with the goal of using plants as a platform to deliver a cost-effective recombinant vaccine against the viral infection. They have successfully expressed viral antigens in the tobacco plants, and the genetically modified plants are grown under laboratory conditions.

“Once the plant has grown for two months, the biomass – leaves – is collected. The crude protein from the plant is extracted. From this crude form, the E1 and E2 proteins are extracted through purification. The extracted recombinant protein can be used in the oral form or injected as vaccine,” says Mr. Varghese.

After the animal trials, the duo plan to patent the technology and transfer it.

According to Mr. Sathishkumar, once the technology is transferred, the London university, or any national institute, or manufacturer to whom the technology is transferred, can take it further for human clinical trials.

With permission from the Government, the large-scale cultivation of transgenic tobacco plants under controlled conditions will be possible for mass extraction of the protein to be used as vaccine.

“If this proves a success, other edibles like tomato can also be used as candidates. For example, transgenic tomato seeds can be used for cultivation of tomato plants. The harvested tomatoes, which will contain the recombinant E1 and E2 proteins, can be used as such. The best form will be to dry the tomatoes and powder them for preservation purposes. This can be used as an edible vaccine,” says Mr. Sathishkumar.

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