Low molecular weight glutenins in wheat-dependant, exercise-induced anaphylaxis: allergenicity and antigenic relationships with omega 5-gliadins.
BACKGROUND
Adults suffering from wheat-dependant, exercise-induced anaphylaxis (WDEIA) develop IgE directed against wheat omega5-gliadins (major allergens for this allergy) and against wheat low-molecular weight glutenin subunits (LMW-GS). However, the ability of LMW-GS to trigger an inflammatory response is still unknown. It also remains to be determined if IgE from these patients bind the same epitopes on LMW-GS and omega5-gliadins or if the epitopes are independent.


METHODS
WDEIA patients were selected and skin prick tests (SPTs) were performed on them using commercial gluten, wheat flour extracts, prolamin fractions and a purified natural LMW-GS P42. The IgE-binding ability of natural and recombinant wheat prolamins was verified by immunoblot experiments. Cross-reactivity between LMW-GS and omega5-gliadins was studied by immunoblot inhibition experiments, using purified natural omega5-gliadin as an inhibitor.


RESULTS
Patients developed positive SPTs with natural LMW-GS fractions and/or with the purified LMW-GS P42. Natural and recombinant LMW-GS were highly reactive with patient IgE in immunoblot experiments, as was omega5-gliadin. However, differences in reactivity were evident within the LMW-GS group. Except for one recombinant LMW-GS (P73), IgE cross-reactivity between LMW-GS and natural omega5-gliadin was only partial.


CONCLUSIONS
LMW-GS are able to promote local inflammation and they share common epitopes with omega5-gliadins. The nature of these epitopes is discussed. LMW-GS also carried specific epitopes, completely independent from the omega5-gliadin epitopes. Thus, LMW-GS behaved partly as independent allergens.
Bouchez-Mahiout
Isabelle
I
UMR 206 Chimie-Biologique, INRA-AgroParisTech, Thiverval-Grignon, France. bouchez@grignon.inra.fr
Snégaroff
Jacques
J
Tylichova
Martina
M
Pecquet
Catherine
C
Branlard
Gérard
G
Laurière
Michel
M
D000328:Adult; D000485:Allergens / Q000009:adverse effects / Q000276:immunology; D000595:Amino Acid Sequence; D000707:Anaphylaxis / Q000209:etiology / Q000276:immunology; D000941:Antigens / Q000276:immunology; D019086:Bridged Bicyclo Compounds, Heterocyclic; D003429:Cross Reactions; D015444:Exercise; D005903:Gliadin / Q000009:adverse effects / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D005983:Glutens / Q000009:adverse effects / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D008875:Middle Aged; D010880:Piperidines; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D012882:Skin Tests; D014908:Triticum / Q000276:immunology; D021182:Wheat Hypersensitivity / Q000276:immunology*; D055815:Young Adult
D000485:Allergens; D000941:Antigens; D019086:Bridged Bicyclo Compounds, Heterocyclic; C447822:MOL 6131; D010880:Piperidines; D011994:Recombinant Proteins; D007073:Immunoglobulin E; D005983:Glutens; D005903:Gliadin; C037302:glutenin