www.czu.cz ; www.raupp.info

Russian scientists are currently creating a pleasant and harmless vaccine,
and edible one at that. So far, they managed to incorporate the protein
gene ? HIV antigen in tomatoes. The research is supported by International
Science and Technology Center, July 2004.

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!

[www.informnauka.ru]

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