By Stephen Daniells

Advances in the field of genetic engineering may produce plants with little
or no allergens, but there are limits to this approach, say Australian
researchers.
Genetic modification of plants and crops has long been touted as a means of
producing hypoallergenic foods, but real progress in this area is limited by
overcoming the "essential requirement for some of the major allergenic
proteins for normal plant function," wrote Mohan Singh and Prem Bhalla from
the University of Melbourne.

"It is very unlikely that plant foods can be engineered to be completely
free of allergens, but the removal of a few immunodominant allergens might
reduce the severity of allergic reactions, substantially improving the
safety of foods," they add in the journal Trends in Plant Science.

"It is hoped that, over time, hypoallergenic food products from genetically
engineered plants will reach market shelves."

Food allergy is an area of growing concern for the industry and the public.
According to the Food Allergy and Anaphylaxis Network, over 12 million
Americans have food allergies, equivalent to four percent of the population.

Allergies to milk, eggs, peanuts, tree nuts, soy, fish, shellfish, and
account for 90 percent of all food-allergic reactions in the US, says the
network.

In the new research focus, Singh and Bhalla from the Australian Research
Council Centre of Excellence for Integrative Legume Research at the
University of Melbourne review the potential of genetic engineering to
produce hypoallergenic plants.

Allergen-free peanuts

Significant research has focused on removing the allergens from peanuts, as
these can be deadly. The science has focused on three types of proteins: Ara
h1, h2, and h3.

"Of these three allergenic proteins, the Ara h 2 glycoprotein is the most
potent allergen, with nearly 50-fold greater potency than Ara h 1," wrote
Singh and Bhalla.

Using gene silencing techniques, researchers have reported the production of
peanut plants with virtually no Ara h2, said the reviewers.

Allergen-free tomatoes

Another plant that has received research attention is the humble tomato,
said the Melbourne-based scientists. In this case, the goal has been to
remove the ns-LTP protein from the fruit.

Despite advances in producing plants with ns-LTP suppression, other
allergens exist in tomatoes that have evaded modification. The allergenic
proteins, Lyc e 1, Lyc e 2 and Lyc c 3. Lyc e 1 are associated with
profilin, a ubiquitous protein found in all eukaryotic cells, and essential
for plant cell function. Attempts to modify the genes that produce these
proteins have been unsuccessful, said Singh and Bhalla.

"The transgenic plants exhibited severe growth retardation along with yield
reduction, however, and some transgenic lines did not bear any fruit.

"These results highlight the obstacles in removing certain plant allergenic
proteins that perform essential cellular housekeeping functions," they
added.

Improving the image of GM

"The availability of foods with enhanced safety profiles might help to
increase the consumer acceptability of genetic engineering," wrote Singh and
Bhalla.

"Genetically engineered hypoallergenic plants might one day be established
as a useful adjunct to allergen avoidance as a strategy for the management
of food allergy symptoms," they concluded.

All food allergies gone within a decade?

In 2006, Dutch Dutch researchers told the BA Festival of Science in England
that food allergies could be consigned to the history books within a decade
if the combination of biotechnology and vaccines work as planned.

Dr. Ronald van Ree from the University of Amsterdam told attendees in
Norwich that the key finding of the research presented was: A clever
combination of biotechnology (hypo-allergenic recombinant allergens) and
vaccine-development (novel adjuvants based on anti-inflammatory molecules
from pathogens) [to] provide new tools to treat food allergy.

Despite offering a potentially life-saving solution for millions around the
world, acceptance of GM peanuts is not guaranteed. The GM tag continues to
be one of the biggest challenges for consumer acceptance, particularly in
Europe and most notably in the UK.
www.checkbiotech.org