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Some days ago Gwynneth Thomas expressed her concern about possible
introduction of allergens by genetic engineering. The example she gave was
the introduction of genes from brazil nut to soybeans. The possible adverse
effects of this modifications was however detected in a very early state
and the production of this kind of  soy was suspended.

The topic of genetically modification is of great concern, especially in
Europe where many consumers react quite outrageous to the idea of having to
eat (without knowing) genetically modified food. That is why the European
Commission has made labelling of any genetically modified food or
ingredient compulsory.

Twere are two scenario's, the bad one and the good one!
The bad one first.
        Most genetic engineers are working on the improvement of the functional
properties of wheat, especially the breadmaking properties. Because this
property is strongly related to the amount and structure of high mol-weight
(HMW) glutenin, most work has been done with the aim to increase the level
of this HMW-glutenin fraction. Though celiac-toxicity is predominantly
attributed to the gliadin fraction of gluten (i.e. the alcohol soluble
wheat protein fraction) there is actually no proof that glutenin (which is
the fraction of the wheat proteins which is not soluble in water and
neither in salt solution, nor in alcohol) is harmless. In addition, it is
also not exactly known which fraction is causing IgE mediated intolerance
(i.e the true wheat allergy). Though it is generally believed that mainly
the albumin/globulin fractions of wheat are responsible, quite recently
some Japanese scientists discovered that glutenin (especially the low mol
weight fraction), as well as alpha gliadin and gamma gliadins are very
reactive with sera from known wheat allergic persons and they suspect
glutenin to be a strong allergen.
Though one might reason that increasing the amount of glutenin is harmless
because wheat allergic people are so sensitive to wheat that an increase of
glutenin would not make any difference, this might be too simple. If in the
future food industry will be forced to pay more attention to avoiding
contamination of foods with "edible extraneous" material like wheat, their
task will be more difficult if wheat is becoming more toxic than it is now.
By consequence there is a good reason for testing these genetically
engineered wheat cultivars  to get information about  a possible increase
in celiac-toxicity/allergenicity!

And the good one!
It might be possible to remove the toxic amino-acid motifs by genetic
engineering e.g. by silencing the genes expressing the proteins involved.
The big challenge is however to delete these proteins without affecting the
functional properties of the wheat. This perhaps could be an impossible
task as long it is not exactly known which peptide motifs are exacerbating
the toxic effect. But gliadins, probably the most toxic proteins for
celiacs are also most probably less "functional" as glutenins. So it might
be possible perhaps to silence gliadin expressing genes or to modify the
aminoacid sequence. But it could end also in adisillusion: to quote a
saying attributed to Donald Kasarda (heard from Dr Wieser): "genetically
modified wheat... we do have that already...we use to call it maize!". The
findings of Maruyama et al. are promising because in fact LMW glutenins are
not known as the most "functional"  proteins (anyway less functional than
high mol weight glutenins) so their silencing could result in less
allergenic but still functional wheat.  At the moment the only possibility
to prepare hypoallergenic wheat is to extensively hydrolyse the wheat
proteins. This inevitably destroys functional properties.
Whether the de-toxification scenario can be applied to celiac toxicity has
to be awaited.
There is a big chance that the German government will endorse (and will
make funds available)  to develop a genetically modified wheat with the
toxic amino-acid motifs removed. If this project succeeds it will be a big
step forward!

Lit:
1) Altpeter F., Vasil V., Srivasta V., Vasil I.K., Integration of and
expression or the high-molecular weight glutenin subunit 1Ax1 gene into
wheat. Nature Biotechnology 14 (1996) 1155-1159

2) Blechl A.E., Anderson O.D., Expression of a novel high molecular-weight
glutenin subunit gene in transgenic wheat. Nature Biotechnology 14 (1996)
 875-879

3) Barro F., Rooke L., Bekes F., Gras P., Tatham A.S., Fido R., Lazzeri
P.A., Shewry P.R., Barcelo P., Transformation of wheat with high molecular
weight subunit genes result in improved functional properties. Nature
Biotechnology 15 (1997) 1295-1299.

4) Maruyama N., Ichise K., Katsube T., Kishimoto T., Kawase S., Matsumura
Y, Takeuchi Y., Sawada T., Utsimi S., Identification of major wheat
allergens by means of the Escherichia coli expression system. Eur. J.,
Biochem. 255, 739-745 (1998)

Frederik Willem Janssen, Zutphen, The Netherlands