Koning, F.

Smulders, M.J.M.

English

Wageningen Yield 

Gluten toxicity, how to get rid of it?
Frits Koning1, Rene Smulders 2
1 De part ment of Immunohematology and Blood Trans fu sion, 
Leiden Uni ver sity Med i cal Cen tre, Leiden, The Neth er lands
2 Plant Re search In ter na tional, Wageningen UR, The Neth er lands
In 1993 Lundin and colleagues first described the presence of gluten-specific T cells in
small intestinal biopsies of coeliac disease (CD) patients [1]. A large number of studies
have since established that such T cells can be specific for a large and diverse array of
peptides derived from the gliadins as well as the glutenins ([2-5], references in [6]).
Invariably, these peptides can trigger T-cell responses only when bound to the disease
predisposing HLA-DQ2 or HLA-DQ8 molecules. This provides an explanation for the
well established association between these HLA-molecules and disease development. It 
also became evident that many of these peptides require modification by the enzyme
tissue transglutaminase, a modification that introduces negative charges into gluten
peptides, thus enhancing the binding of these peptides to either HLA-DQ2 or HLA-
DQ8 [8]. Not only wheat is off-limits to CD patients: barley and rye are also known to
contain a variety of proteins that are just as harmful as the gluten proteins from wheat
[8, 9]. Oat seems an exception as it is tolerated by most patients, partly due to a low
content of gluten-like prolamin proteins [8-10]. 
Thus, CD patients usually have T cells specific for an array of gluten and gluten-like
peptides that originate from all types of gluten proteins and homologues in other cereals. 
At present the introduction of a gluten-free diet is the only but highly-effective treatment 
option. This diet, however, has several drawbacks. It is relatively cumbersome, difficult
to adhere to, expensive and is deficient in several nutrients and fibers. Many patients feel 
insecure, especially when eating out or while travelling. Thus, there is an unmet need for 
alternatives to the gluten-free diet. 
With the identification of the harmful sequences in gluten and gluten-like proteins it has
become possible to initiate studies aimed at reducing or eliminating the toxicity of such
proteins and/or wheat. Early studies indicated that substantial differences existed
between wheat varieties regarding their "toxicity profile" [11-13]. Some of those could
be attributed to differences in the genetic make-up of the three genomes that comprise
the complex hexaploid bread wheat, the A-, B- and D-genome [12, 13]. More recently
we embarked on a large-scale study to map the toxicity of the α-gliadins, based on the
observation that the α-gliadins are among the most immunogenic gluten proteins and
II. Cli ni cal re search re ports 63
contain four well-characterized peptides involved in CD [2, 4, 5]. We analyzed over
3,000 α-gliadin genes in the database to determine the full extent of the natural
variability that is present in these genes and in the known T-cell stimulatory peptides in
these proteins in particular [14]. The results indicated that many natural variants of these 
immunogenic α-gliadin peptides exist; an example is given in Fig. 1.
We could classify all identified variants as belonging to one of the three genomes
based on differences in the complete gene sequences. Moreover we synthesized all
variants of the four known T-cell peptides that we had identified, and tested these for
binding to HLA-DQ2 or HLA-DQ8 as well as for recognition by T cells derived from
small intestinal biopsies of CD patients ([14], Fig. 2). The results demonstrated that no 
α-gliadin proteins exist that lack all T-cell stimulatory epitopes ([14], Fig. 2). Based
on these results it can be concluded that it would be impossible to generate CD-safe
wheat through conventional breeding programs. Substantial differences, however,
were observed between the genes encoded by the three genomes: while the D-genome
α-gliadins are by far the most toxic, the B-genome encoded α-gliadins are the least
toxic and the A-genome encoded genes have an intermediate toxicity profile.
64 Gluten toxicity, how to get rid of it?
Sequence Oc cur rence in database
PFPQPQLPY 986
PFLQPQLPY 106
PFSQPQLPY 190
PFPHPQLPY 29
ETC
FIG. 1.  Many natural vairants of known immunogenic alphy-gliadin peptides
DQ2-α1 DQ2-α2 DQ2-α3 DQ8-α1
A + - + -
B - - - +
D + + + +
FIG. 2.  No al pha-glia din pro teins exist that lack all T cell sti mu la to ry epi to pes
Close examination of the results, however, indicated that there are natural variants of
all T-cell stimulatory epitopes that do not induce T-cell responses. For example, the
A-genome encodes a variant of the DQ2-α2 epitope that is not immunogenic: while
the sequence of this epitope on the D-genome is PQPQLPYPQ, the A-genome
encodes PQPQLPYSQ and this P to S substitution results in a peptide that does not
induce T-cell responses [14]. Similarly, natural variants of the other three T-cell
stimulatory peptides have been identified that lack T-cell stimulatory properties. 
These results allow a novel approach to eliminate gluten toxicity: while the D-genome
α-gliadin gene encodes four toxic epitopes, it is possible, , by combining the genetic
information of the A- and B-genome encoded α-gliadins, to generate a new gene that
encodes a  that is not toxic for CD patients ([14], Fig. 3). At the peptide level, we have
provided proof of principle for this approach and we envisage that similar approaches
can be taken to generate non-toxic variants for the other gliadin and glutenin proteins in
wheat gluten. In this respect the high molecular weight glutenins are of particular
interest as these, to a large extent, determine the baking properties of gluten. Genes
encoding such safe-gluten proteins could be introduced into safe cereals for production
of safe-gluten that could be used for the fabrication of gluten-free foods with markedly
enhanced quality in terms of nutritional value, taste and baking properties. 
Acknowledgement
This research was financed in part by the Celiac Disease Consortium, an Innovative
Cluster approved by the Dutch Genomics Initiative and partially funded by the Dutch
Government (BSIK03009). 
II. Cli ni cal re search re ports 65
D
A
B/S
New
FIG. 3.   New non-to xic glu ten gene
References
1. Lundin KE, Scott H, Hansen T, et al. Gliadin-spe cific, HLA-DQ(α1*0501,β1*0201)
re stricted T cells iso lated from the small in tes ti nal mu cosa of ce liac dis ease 
pa tients. J Exp Med 1993; 178: 187-196.
2. Van de Wal Y, Kooy Y, van Veelen P, et al. Small in tes ti nal cells of ce liac 
dis ease pa tients rec og nize a nat u ral pep sin frag ment of gliadin. Proc Natl Acad
 Sci USA 1998; 95: 10050-10054.
3. Van de Wal Y, Kooy YMC, van Veelen P, et al. Glutenin is in volved in the
 glu ten-driven mucosal T cell re sponse. Eur J Immunol 1999; 29: 3133-3139.
4. Arentz-Hansen H., Körner R., Molberg Ø, et al. The in tes ti nal T cell re sponse to  
 α-gliadin in adult ce liac dis ease is fo cused on a sin gle deamidated glutamine 
tar geted by tis sue transglutaminase. J Exp Med 200; 191: 603-612.
5. Vader W, Kooy Y, van Veelen P, et al. The glu ten re sponse in chil dren with
re cent on set ce liac dis ease. A highly di verse re sponse to wards mul ti ple gliadin
 and glutenin de rived pep tides. Gastroenterology 2002; 122: 1729-1737.
6. Stepniak D, Koning F. Ce liac Dis ease: sandwiched be tween in nate and adap tive
 im mu nity. Hum Immunol 2006; 67: 460-468.
7. Van de Wal Y, Kooy Y, van Veelen P, et al. Cut ting Edge: Se lec tive deamida-
 tion by tis sue transglutaminase strongly en hances gliadin-spe cific T cell
 re ac tiv ity. J Immunol 1998; 161: 1585-1588.
8. Vader W, de Ru A, van de Wal Y, et al. Spec i fic ity of tis sue transglutaminase
 ex plains ce real tox ic ity in ce liac dis ease. J Exp Med 2002; 195: 643-649.
9. Vader W, Stepniak D, Bunnik EM, et al. Char ac ter iza tion of ce real tox ic ity for
 ce liac dis ease pa tients based on pro tein homology in grains. Gastroenterology
 2003; 125:  1105-1113.
10. Arentz-Hansen H, Fleckenstein B, Molberg Ø, et al. The mo lec u lar ba sis for oat
 in tol er ance in pa tients with ce liac dis ease. PLoS Med i cine 2004; 1: 84-92.
11. Spaenij-Dekking L, Kooy-Winkelaar Y, van Veelen P, et al. Nat u ral vari a tion in
 tox ic ity of wheat ac ces sions for ce liac dis ease pa tients. Po ten tial for se lec tion and
 breed ing of non-toxic wheat va ri et ies. Gastroenterology 2005; 129: 797-806.
12. Molberg Ø, Uhlen AK, Jensen T, et al. Map ping of glu ten T-cell epitopes in the
 bread wheat an ces tors: im pli ca tions for ce liac dis ease. Gastroenterology 2005;
 128: 393-401.
66 Gluten toxicity, how to get rid of it?
13. Van Herpen TWJM, Goryunova SV, van der Schoot J, et al. Al pha-gliadin genes
 from the A, B, and D genomes of wheat con tain dif fer ent sets of ce liac dis ease
 epitopes. BMC Genomics 2006; 7: 1.Mitea C, Salentijn EMJ, van Veelen P, et al.
A uni ver sal ap proach to elim i nate an ti genic prop er ties of al pha-gliadin pep tides
 in ce liac dis ease. PLoS One 2010; 5: e15637. 
14. Mitea C, Salentijn EMJ, van Veelen P, et al. A uni ver sal ap proach to elim i nate
 an ti genic prop er ties of al pha-gliadin pep tides in ce liac dis ease. PLoS One 210; 5:
 e15637.
II. Cli ni cal re search re ports 67


A uni ver sal ap proach to elim i nate an ti genic prop er ties of al pha-gliadin pep tides in ce liac dis ease. PLoS One 210; 5: e15637. II. Cli ni cal re search re ports 67

Al pha-gliadin genes from the A, B, and D genomes of wheat con tain dif fer ent sets of ce liac dis ease epitopes. BMC Genomics 2006; 7: 1.Mitea

Ce liac Dis ease: sandwiched be tween in nate and adap tive im mu nity. Hum Immunol

Char ac ter iza tion of ce real tox ic ity for ce liac dis ease pa tients based on pro tein homology in grains. Gastroenterology

Cut ting Edge: Se lec tive deamidation by tis sue transglutaminase strongly en hances gliadin-spe cific T cell re ac tiv ity.

Gliadin-spe cific, HLA-DQ(α1*0501,β1*0201) re stricted T cells iso lated from the small in tes ti nal mu cosa of ce liac dis ease pa tients.

Glutenin is in volved in the glu ten-driven mucosal T cell re sponse.

Map ping of glu ten T-cell epitopes in the bread wheat an ces tors: im pli ca tions for ce liac dis ease. Gastroenterology 2005; 128: 393-401. 66 Gluten toxicity, how to get rid of it?

Nat u ral vari a tion in tox ic ity of wheat ac ces sions for ce liac dis ease pa tients. Po ten tial for se lec tion and breed ing of non-toxic wheat va ri et ies. Gastroenterology

Small in tes ti nal cells of ce liac dis ease pa tients rec og nize a nat u ral pep sin frag ment of gliadin.

Spec i fic ity of tis sue transglutaminase ex plains ce real tox ic ity in ce liac dis ease.

The glu ten re sponse in chil dren with re cent on set ce liac dis ease. A highly di verse re sponse to wards mul ti ple gliadin and glutenin de rived pep tides. Gastroenterology

The in tes ti nal T cell re sponse to α-gliadin in adult ce liac dis ease is fo cused on a sin gle deamidated glutamine tar geted by tis sue transglutaminase.

The mo lec u lar ba sis for oat in tol er ance in pa tients with ce liac dis ease. PLoS Med i cine

Gluten toxicity, how to get rid of it?

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Gluten toxicity, how to get rid of it?

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