The findings are
presented in a new academic dissertation at the university.
To produce drugs
with the help of plants is a rapidly growing research field that
offers new potential to combat diseases. At Örebro University
researchers have the goal of developing inexpensive and safe
protection against HIV, in the form of plants that contain a
vaccine against the virus and can be cultivated all over the world.
If they succeed, it will be difficult to exaggerate the
significance of this for millions of people around the world, not
least in the poorest countries.
“A major problem
with the HIV virus is that it mutates rapidly and therefore exists
in several different variants. In other words, it’s not possible to
create an effective vaccine that is based on the entire virus.
Moreover, this would be far too risky. Instead, we have selected a
protein, p24, that exists in all HIV viruses and looks roughly the
same in the various virus lines,” says Ingrid Lindh, author of the
dissertation.
To get plants to
produce the p24 protein, the gene that underlies the process must
be a part of their own genetic make-up, but since it’s impossible
to transfer the gene directly from the virus to the plant, the
researchers had to take a detour. This was done by first placing
the gene into a bacterium that could then transmit it to the
plants. The attempt succeeded; the plants produced p24 and also
passed on this ability to their offspring.
In the next phase,
mice were fed with the p24 plants, and these trials also proved to
be successful. The mice’s immune defense reacted just as the
researchers had hoped, producing antibodies against the protein. In
other words, this functioned as a vaccine. This raises hopes that a
similar reaction in humans would make them immune to HIV.
“It is highly
probable that the human immune system will respond in the same
manner, but this is not to say that this would be sufficient to
provide complete protection.”
To increase the
potency of the vaccine, these scientists are therefore going to add
more HIV proteins together with other compounds that reinforce the
body’s reaction to HIV-specific proteins. In parallel with this,
they will work to select a suitable vegetable that is easy to
cultivate in different climates and is readily accepted in
different cultures. Thus far, thale cress (Arabidopsis
thaliana) has been used as an experimental plant, a common wild
plant that is related to mustard and cabbage and has the great
advantage of being well mapped genetically.
“The carrot is a
good candidate for producing an edible vaccine, not least because
it can be eaten raw, which reduces the risk of the proteins being
destroyed by heating. What’s more, it’s a biennial, which means
that it doesn’t go to seed the first year, making it easier to
ensure that it doesn’t spread its genes to other plants close by,”
explains Ingrid Lindh.