Relevance of IgE binding to short peptides for the allergenic activity of food allergens.
BACKGROUND
Analysis of IgE antibody binding to epitopes provides information for food allergy diagnosis and management and construction of hypoallergenic candidate vaccines, but the contribution of sequential epitopes to functionally relevant IgE binding is not fully understood.


OBJECTIVE
We sought to study the impact of IgE-binding peptides described as major sequence epitopes in the literature on IgE-binding capacity of 2 selected food allergens.


METHODS
IgE-binding peptides of the food allergens Ara h 2 (peanut) and Pen a 1 (shrimp) were identified. Synthetic soluble peptides representing the identified sequences were assessed for their capacity to inhibit IgE binding to the parent allergens by means of ELISA and in mediator release assay. The IgE-binding capacity of unfolded recombinant (r) Ara h 2 was analyzed. A hybrid tropomyosin carrying the IgE-binding regions of Pen a 1 grafted into the structural context of the nonallergenic mouse tropomyosin was applied in ELISA inhibition experiments and ImmunoCAP analysis.


RESULTS
Although IgE-binding peptides representing sections of the allergen sequences were detected, no relevant capacity to inhibit the IgE binding to the parent allergen in ELISA or basophil activation test was observed. Unfolded rAra h 2 showed reduced IgE-binding capacity compared with folded rAra h 2 and failed to elicit mediator release. Hybrid tropomyosin bound less IgE than rPen a 1 in ImmunoCAP analysis and revealed marginal inhibitory capacity.


CONCLUSIONS
Peptides identified as major sequence epitopes on Pen a 1 and Ara h 2 show little contribution to the IgE binding of the allergens studied.
Albrecht
Melanie
M
Division of Allergology, Paul-Ehrlich-Institut, Langen, Germany.
Kühne
Yvonne
Y
Ballmer-Weber
Barbara K
BK
Becker
Wolf-Meinhard
WM
Holzhauser
Thomas
T
Lauer
Iris
I
Reuter
Andreas
A
Randow
Stefanie
S
Falk
Sabine
S
Wangorsch
Andrea
A
Lidholm
Jonas
J
Reese
Gerald
G
Vieths
Stefan
S
D055516:2S Albumins, Plant / Q000276:immunology*; D000485:Allergens / Q000276:immunology*; D000818:Animals; D052179:Antigens, Plant; D018604:Epitope Mapping; D000939:Epitopes / Q000276:immunology; D005512:Food Hypersensitivity / Q000276:immunology*; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D051379:Mice; D010446:Peptide Fragments / Q000276:immunology; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000276:immunology; D014335:Tropomyosin / Q000276:immunology / Q000378:metabolism; D014612:Vaccines / Q000276:immunology
D055516:2S Albumins, Plant; D000485:Allergens; D052179:Antigens, Plant; C500890:Ara h 2 allergen, Arachis hypogaea; D000939:Epitopes; D006023:Glycoproteins; C513564:Pen a 1 allergen, Penaeus aztecus; D010446:Peptide Fragments; D011994:Recombinant Proteins; D014335:Tropomyosin; D014612:Vaccines; D007073:Immunoglobulin E