Dataset Information

Current challenges in detecting food allergens by shotgun and targeted proteomic approaches: a case study on traces of peanut allergens in baked cookies.

ABSTRACT: There is a need for selective and sensitive methods to detect the presence of food allergens at trace levels in highly processed food products. In this work, a combination of non-targeted and targeted proteomics approaches are used to illustrate the difficulties encountered in the detection of the major peanut allergens Ara h 1, Ara h 2 and Ara h 3 from a representative processed food matrix. Shotgun proteomics was employed for selection of the proteotypic peptides for targeted approaches via selective reaction monitoring. Peanut presence through detection of the proteotypic Ara h 3/4 peptides AHVQVVDSNGNR (m/z 432.5, 3+) and SPDIYNPQAGSLK (m/z 695.4, 2+) was confirmed and the developed method was able to detect peanut presence at trace levels (?10 ?g peanut g(-1) matrix) in baked cookies.

SUBMITTER: Pedreschi R

PROVIDER: S-EPMC3296995 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Current challenges in detecting food allergens by shotgun and targeted proteomic approaches: a case study on traces of peanut allergens in baked cookies.

Pedreschi Romina R Nørgaard Jørgen J Maquet Alain A

Nutrients 20120221 2

There is a need for selective and sensitive methods to detect the presence of food allergens at trace levels in highly processed food products. In this work, a combination of non-targeted and targeted proteomics approaches are used to illustrate the difficulties encountered in the detection of the major peanut allergens Ara h 1, Ara h 2 and Ara h 3 from a representative processed food matrix. Shotgun proteomics was employed for selection of the proteotypic peptides for targeted approaches via se ...[more]

PMID: 22413066

Similar Datasets

Project description:BACKGROUND:Most children with detectable peanut-specific IgE (P-sIgE) are not allergic to peanut. We addressed 2 non-mutually exclusive hypotheses for the discrepancy between allergy and sensitization: (1) differences in P-sIgE levels between children with peanut allergy (PA) and peanut-sensitized but tolerant (PS) children and (2) the presence of an IgE inhibitor, such as peanut-specific IgG4 (P-sIgG4), in PS patients. METHODS:Two hundred twenty-eight children (108 patients with PA, 77 PS patients, and 43 nonsensitized nonallergic subjects) were studied. Levels of specific IgE and IgG4 to peanut and its components were determined. IgE-stripped basophils or a mast cell line were used in passive sensitization activation and inhibition assays. Plasma of PS subjects and patients submitted to peanut oral immunotherapy (POIT) were depleted of IgG4 and retested in inhibition assays. RESULTS:Basophils and mast cells sensitized with plasma from patients with PA but not PS patients showed dose-dependent activation in response to peanut. Levels of sIgE to peanut and its components could only partially explain differences in clinical reactivity between patients with PA and PS patients. P-sIgG4 levels (P = .023) and P-sIgG4/P-sIgE (P < .001), Ara h 1-sIgG4/Ara h 1-sIgE (P = .050), Ara h 2-sIgG4/Ara h 2-sIgE (P = .004), and Ara h 3-sIgG4/Ara h 3-sIgE (P = .016) ratios were greater in PS children compared with those in children with PA. Peanut-induced activation was inhibited in the presence of plasma from PS children with detectable P-sIgG4 levels and POIT but not from nonsensitized nonallergic children. Depletion of IgG4 from plasma of children with PS (and POIT) sensitized to Ara h 1 to Ara h 3 partially restored peanut-induced mast cell activation (P = .007). CONCLUSIONS:Differences in sIgE levels and allergen specificity could not justify the clinical phenotype in all children with PA and PS children. Blocking IgG4 antibodies provide an additional explanation for the absence of clinical reactivity in PS patients sensitized to major peanut allergens.

Project description:BackgroundThe prevalence of sensitization to ragweed has risen in North America and across Europe. Although the pectate lyase Amb a 1, the major allergen of ragweed, was identified as long ago as the 1960s, little is known about the allergenicity of the 5 Amb a 1 isoallergens and other allergens present in ragweed pollen. Ragweed extracts and purified Amb a 1 isoallergens have now been characterized for their allergenic potential to determine whether a single Amb a 1 isoallergen, several isoallergens or a combination with other allergens should be included in a recombinant SIT vaccine.MethodsExtracts from North American short ragweed (Ambrosia artemisiifolia) pollen were investigated by mass spectrometry (MS), 2D-PAGE and immunoblotting. Furthermore, Amb a 1 isoallergens were purified and IgE reactivity determined by immunoblotting and IgE inhibition.Results2D-PAGE and MS of ragweed extract proved the presence of all 5 known Amb a 1 isoallergens, of which Amb a 1.01 represents the dominant form. Additionally all other ragweed allergens known by sequence (Amb a 3, Amb a 4, Amb a 5, Amb a 6, Amb a 8, Amb a 9, Amb a 10) were identified. The highest IgE reactivity by immunoblotting was observed for Amb a 1.01 followed by Amb a 1.03; other Amb a 1 isoallergens as well as other detected ragweed allergens showed only weak IgE reactivity. All isoallergens with the exception of Amb a 1.04, which is only of low abundance in ragweed extract, were purified. Similar to the immunoblot analysis with crude extract, the purified isoallergens Amb a 1.02 and Amb a 1.05 showed weak IgE binding, whereas Amb a 1.01 and Amb a 1.03 had high IgE reactivity. First IgE inhibition experiments suggest that Amb a 1.01 contains all relevant IgE epitopes.ConclusionsAmb a 1.01 is the most abundant Amb a 1 isoallergen, and presumably the most important ragweed allergen. However, a larger panel of ragweed-allergic subjects has to be analyzed with regard to IgE and T cell reactivities, to be able to choose a candidate for a recombinant vaccine for specific immunotherapy of ragweed allergy.

Dataset Information

Current challenges in detecting food allergens by shotgun and targeted proteomic approaches: a case study on traces of peanut allergens in baked cookies.

Publications

Current challenges in detecting food allergens by shotgun and targeted proteomic approaches: a case study on traces of peanut allergens in baked cookies.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets