Identification of IgE Binding to Api g 1‐Derived Peptides

Abstract

Celery is a frequent cause of food allergy in pollen-sensitized patients and can induce severe allergic reactions. Clinical symptoms cannot be predicted by skin prick tests (SPTs) or by determining allergen-specific immunoglobulin E (IgE). Our aim was to identify specific IgE binding peptides by using an array technique. For our study, the sera of 21 patients with positive double-blind, placebo-controlled food challenge (DBPCFC) to celery, as well as the sera of 17 healthy patients were used. Additionally, all patients underwent skin tests along with determinations of specific IgE binding. The major allergen of celery Api g 1.0101 (Apium graveolens) was synthesized as an array of overlapping peptides and probed with the patients' sera. We developed an improved immunoassay protocol by investigating peptide lengths, peptide densities, incubation parameters, and readout systems, which could influence IgE binding. Sera of celery-allergic patients showed binding to three distinct regions of Api g 1.0101. The region including amino acids 100 to 126 of Api g 1.0101 is the most important region for IgE binding. This region caused a fivefold higher binding of IgE from the sera of celery-allergic patients compared to those of healthy individuals. In particular, one peptide (VLVPTADGGSIC) was recognized by all sera of celery-allergic patients. In contrast, no binding to this peptide was detected in sera of the healthy controls. Our improved assay strategy allows us to distinguish between celery-allergic and healthy individuals, but needs to be explored in a larger cohort of well-defined patients.

Allergenic activity of different tomato cultivars in tomato allergic subjects

“…If the differences were associated with the expression of allergen isoforms, a comparative protein profile (2D gel electrophoresis) would be necessary. Alternatively, if the reason was due to diversity of epitopes, a comparative epitope mapping technique like overlapping peptide scanning would be appropriate and should be considered in future investigations.…”

Guidelines on the management of IgE-mediated food allergies

“…Novel diagnostic options are emerging with the determination of specific IgE against overlapping synthetic linear peptides. Although this approach has been described to date for milk [ 147 , 148 , 149 ], peanut [ 150 , 151 ], egg [ 152 ], shrimp [ 153 , 154 ], and celery [ 155 ], there are currently no peptide-based tests available on the market that can currently be recommended for routine practice.…”

Molecular diagnosis of fruit and vegetable allergy

“…CRD approach did not facilitate discrimination between celeriac-sensitized but tolerant patients and celeriac allergic patients. Using overlapping peptides in a peptide-microarray sera of celeriac allergic patients showed in a recently published study [13] binding to three distinct regions of Api g 1.0101. These regions bound IgE of celeriac allergic patients at a higher rate compared with healthy controls.…”