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AIDS And Tomatoes

July 19, 2004

Scientists from Novosibirsk are currently creating a pleasant and harmless vaccine - an edible one. So far, they managed to incorporate the protein gene - HIV antigen in tomatoes. The research is supported by International Science and Technology Center (ISTC).

All patients would be overjoyed to get edible vaccines, contained in vegetables and fruit. Imagine, a patient eats a vaccine and this way gets protected from a dangerous infection. However, this is not a fantasy, the fact being confirmed by the research carried out by scientists all over the world. They are working hard to create an edible vaccine against HIV - a lethal virus. Russian researchers from 'Vector' State Scientific Center for Virology and Biotechnology jointly with the specialists from the Institute for Biological Chemistry and Fundamental Medicine in Novosibirsk, Siberian Institute for Plants Physiology and Biochemistry, Irkutsk, and the scientists from the Department for Agricultural Research, Maryland, USA are also working at this challenge. They are not at the stage of creating the vaccine yet, but the biologists have managed to incorporate the right gene into tomato plants and have proved that the protein required for the vaccine is not only contained in tomato leaves, but in tomato fruit. And this is a considerable achievement.

By the way, tomatoes have not been chosen by chance. The matter is that transgenic plants, which contain protein- HIV antigen, have already been cultivated, but these plants are either not edible, like tobacco, or must be thermally processed, like potatoes, and this way they practically lose their healing powers. To this end tomato serves ideally. The good thing is that this vegetable grows pretty well in Russia, compared to bananas, already used by Western scientists to produce vaccines.   

In order to introduce the right gene into tomatoes, the scientists have constructed the so-called agro-bacterial vector. In the agro bacteria culture the researchers have collected the hybrid plasmid (circular DNA), where they have inserted the artificial protein gene, comprising key sites of two HIP virus proteins. This protein should serve as an antigen in order to get the immune response, and the important point is, not just for one virus protein, but for several ones. It was also required to add the cauliflower mosaic virus gene to the combination, and it was used as a promoter, which controls the functioning of the targeted gene. This complex construction together with the bacteria culture was introduced into tomato germs with the help of an injection needle. Afterwards, the germs were cultivated on a special nutrient medium, and those plants which grew roots, were planted into the soil and cultivated in the hothouse till they matured and developed fruit. With the help of the polymerase chain reaction the researchers have proved that the gene is present in the plants, and with the help of other methods have tested that it works - the protein is present in the leaves and, even more important, in tomato plant fruit.

However, the scientists have gone further - they needed to test if the gene could be passed over to the next generations of plants. They took the seeds of the transgenic tomatoes, couched them and grew the second generation tomatoes, which also happened to be transgenic. The ante-gene protein was present in their fruit.

"The cultivated transgenic tomato plants are worth to be considered in terms of creating an edible vaccine against HIV/AIDS and hepatite B on their basis", this conclusion was made by the scientists. But how is this prospective edible vaccine supposed to work? Protein-antigen would interact with the mucous membrane of the gastrointestinal tract, activating the so-called mucous type of immune protection. As a result, the organism would synthesize antibodies against virus protein. The advantage of edible vaccines compared to injections is the absence of risk of passing over infections, edible vaccines are comparatively inexpensive and do not require any special facilities for storage and transportation. And finally, they are tasty!

Informnauka (Informscience) Agency