Effect of Processing on Fish Protein Antigenicity and Allergenicity.
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ABSTRACT:
SUBMITTER: Jiang X
PROVIDER: S-EPMC8145695 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Worldwide peanuts are often thermally processed before consumption, which might alter its bioactive composition and toxicity. The presented work explores the effect of processing methods such as roasting, frying, and pressure cooking on the bioactive composition, polyphenol profiles, aflatoxin concentration and, allergenicity response of peanuts. Effect of processing methods was assessed by monitoring total polyphenol content (TPC), total flavonoid content (TFC), antioxidant activity by DPPH & ABTS radicals, sensory analysis and, indirect ELISA. Compared to raw peanuts, all processing methods caused significant differences in TPC, TFC, DPPH & ABTS radical scavenging activities. Comparison of polyphenol profiles of raw to processed peanuts by LC-ESI-Q-TOF-MS chromatograms revealed different effects on concentrations of individual bioactive polyphenols. Indirect ELISA showed a significant decrease in the assay response on pressure cooking as compared to other samples. Total aflatoxin concentration was significantly reduced after processing in roasted (97.7%) and fried (98.3%) peanuts. Optimum processing conditions based on bioactive concentration and sensory analysis were found to be, roasting: 150 °C for 10 min, frying: 170 °C for 2 min and, pressure cooking: 15 min. Polyphenol profiles and bioactive constituents of peanuts were influenced by processing and may alter health benefits associated with them hence, vital for research and food industry applications.
| S-EPMC8196134 | biostudies-literature
Project description:PurposeDiagnostic tests for allergen sensitization should reflect real exposure. We made 6 new bony fish extracts, which are consumed popularly in Korea, and evaluated their allergenicity and stability.MethodsWe manufactured fish extracts from codfish, mackerel, common eel, flounder, cutlass, and catfish. Protein and parvalbumin (PV) were evaluated by Bradford assay, 2-site enzyme-linked immunosorbent assay, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), and anti-PV immunoblotting. The immunoglobulin E (IgE) reactivities of the extracts were evaluated with ImmunoCAP and IgE immunoblotting using sera from 24 Korean fish allergy patients, 5 asymptomatic sensitizers, and 11 non-atopic subjects. Stability of the extracts stored in 4 different buffers were evaluated for up to a year.ResultsThe protein concentrations of commercial SPT fish extracts varied with up to a 7.5-fold difference. SDS-PAGE showed marked differences in the PV concentrations of commercial SPT reagents. Specific IgE measurements for the following investigatory fish extracts-iCodfish, iMackerel, and iEel-were concordant with that of their corresponding Phadia ImmunoCAP measurements. ImmunoCAP results showed marked IgE cross-reactivity among the fish species, and the overall sensitivity of ImmunoCAP with the investigatory fish extracts for identification of culprit fish species was 85.7%. The protein and PV concentrations in the investigatory extracts were highly stable in saline with 0.3% phenol-50% glycerol at 4°C for up to a year.ConclusionsThe commercial SPT fish extracts exhibited considerable variation in terms of allergenicity, which may impact on diagnostic accuracy. Our new fish extracts have sufficient allergenicity and stability and may be adequate to various clinical applications.
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Project description:Transcription infidelity (TI) is a mechanism that increases RNA and protein diversity. We found that single-base omissions (i.e., gaps) occurred at significantly higher rates in the RNA of highly allergenic legumes. Transcripts from peanut, soybean, sesame, and mite allergens contained a higher density of gaps than those of nonallergens. Allergen transcripts translate into proteins with a cationic carboxy terminus depleted in hydrophobic residues. In mice, recombinant TI variants of the peanut allergen Ara h 2, but not the canonical allergen itself, induced, without adjuvant, the production of anaphylactogenic specific IgE (sIgE), binding to linear epitopes on both canonical and TI segments of the TI variants. The removal of cationic proteins from bovine lactoserum markedly reduced its capacity to induce sIgE. In peanut-allergic children, the sIgE reactivity was directed toward both canonical and TI segments of Ara h 2 variants. We discovered 2 peanut allergens, which we believe to be previously unreported, because of their RNA-DNA divergence gap patterns and TI peptide amino acid composition. Finally, we showed that the sIgE of children with IgE-negative milk allergy targeted cationic proteins in lactoserum. We propose that it is not the canonical allergens, but their TI variants, that initiate sIgE isotype switching, while both canonical and TI variants elicit clinical allergic reactions.
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Project description:BACKGROUND:Clinical reactions to bony fish species are common in patients with allergy to fish and are caused by parvalbumins of the ?-lineage. Cartilaginous fish such as rays and sharks contain mainly ?-parvalbumins and their allergenicity is not well understood. OBJECTIVE:To investigate the allergenicity of cartilaginous fish and their ?-parvalbumins in individuals allergic to bony fish. METHODS:Sensitization to cod, salmon, and ray among patients allergic to cod, salmon, or both (n = 18) was explored by prick-to-prick testing. Clinical reactivity to ray was assessed in 11 patients by food challenges or clinical workup. IgE-binding to ?-parvalbumins (cod, carp, salmon, barramundi, tilapia) and ?-parvalbumins (ray, shark) was determined by IgE-ELISA. Basophil activation tests and skin prick tests were performed with ?-parvalbumins from cod, carp, and salmon and ?-parvalbumins from ray and shark. RESULTS:Tolerance of ray was observed in 10 of 11 patients. Prick-to-prick test reactions to ray were markedly lower than to bony fish (median wheal diameter 2 mm with ray vs 11 mm with cod and salmon). IgE to ?-parvalbumins was lower (median, 0.1 kU/L for ray and shark) than to ?-parvalbumins (median, ?1.65 kU/L). Furthermore, ?-parvalbumins demonstrated a significantly reduced basophil activation capacity compared with ?-parvalbumins (eg, ray vs cod, P < .001; n = 18). Skin prick test further demonstrated lower reactivity to ?-parvalbumins compared with ?-parvalbumins. CONCLUSIONS:Most patients allergic to bony fish tolerated ray, a cartilaginous fish, because of low allergenicity of its ?-parvalbumin. A careful clinical workup and in vitro IgE-testing for cartilaginous fish will improve patient management and may introduce an alternative to bony fish into patients' diet.
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Project description:MotivationDue to the risk of inducing an immediate Type I (IgE-mediated) allergic response, proteins intended for use in consumer products must be investigated for their allergenic potential before introduction into the marketplace. The FAO/WHO guidelines for computational assessment of allergenic potential of proteins based on short peptide hits and linear sequence window identity thresholds misclassify many proteins as allergens.ResultsWe developed AllerCatPro which predicts the allergenic potential of proteins based on similarity of their 3D protein structure as well as their amino acid sequence compared with a data set of known protein allergens comprising of 4180 unique allergenic protein sequences derived from the union of the major databases Food Allergy Research and Resource Program, Comprehensive Protein Allergen Resource, WHO/International Union of Immunological Societies, UniProtKB and Allergome. We extended the hexamer hit rule by removing peptides with high probability of random occurrence measured by sequence entropy as well as requiring 3 or more hexamer hits consistent with natural linear epitope patterns in known allergens. This is complemented with a Gluten-like repeat pattern detection. We also switched from a linear sequence window similarity to a B-cell epitope-like 3D surface similarity window which became possible through extensive 3D structure modeling covering the majority (74%) of allergens. In case no structure similarity is found, the decision workflow reverts to the old linear sequence window rule. The overall accuracy of AllerCatPro is 84% compared with other current methods which range from 51 to 73%. Both the FAO/WHO rules and AllerCatPro achieve highest sensitivity but AllerCatPro provides a 37-fold increase in specificity.Availability and implementationhttps://allercatpro.bii.a-star.edu.sg/.Supplementary informationSupplementary data are available at Bioinformatics online.
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Project description:Most fish-allergic patients have anti-β-parvalbumin (β-PV) immunoglobulin E (IgE), which cross-reacts among fish species with variable clinical effects. Although the β-PV load is considered a determinant for allergenicity, fish species express distinct β-PV isoforms with unknown pathogenic contributions. To identify the role various parameters play in allergenicity, we have taken Gadus morhua and Scomber japonicus models, determined their β-PV isoform composition and analyzed the interaction of the IgE from fish-allergic patient sera with these different conformations. We found that each fish species contains a major and a minor isoform, with the total PV content four times higher in Gadus morhua than in Scomber japonicus. The isoforms showing the best IgE recognition displayed protease-sensitive globular folds, and if forming amyloids, they were not immunoreactive. Of the isoforms displaying stable globular folds, one was not recognized by IgE under any of the conditions, and the other formed highly immunoreactive amyloids. The results showed that Gadus morhua muscles are equipped with an isoform combination and content that ensures the IgE recognition of all PV folds, whereas the allergenic load of Scomber japonicus is under the control of proteolysis. We conclude that the consideration of isoform properties and content may improve the explanation of fish species allergenicity differences.
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Project description:MotivationDiscovery of novel protective antigens is fundamental to the development of vaccines for existing and emerging pathogens. Most computational methods for predicting protein antigenicity rely directly on homology with previously characterized protective antigens; however, homology-based methods will fail to discover truly novel protective antigens. Thus, there is a significant need for homology-free methods capable of screening entire proteomes for the antigens most likely to generate a protective humoral immune response.ResultsHere we begin by curating two types of positive data: (i) antigens that elicit a strong antibody response in protected individuals but not in unprotected individuals, using human immunoglobulin reactivity data obtained from protein microarray analyses; and (ii) known protective antigens from the literature. The resulting datasets are used to train a sequence-based prediction model, ANTIGENpro, to predict the likelihood that a protein is a protective antigen. ANTIGENpro correctly classifies 82% of the known protective antigens when trained using only the protein microarray datasets. The accuracy on the combined dataset is estimated at 76% by cross-validation experiments. Finally, ANTIGENpro performs well when evaluated on an external pathogen proteome for which protein microarray data were obtained after the initial development of ANTIGENpro.AvailabilityANTIGENpro is integrated in the SCRATCH suite of predictors available at http://scratch.proteomics.ics.uci.edu.Contactpfbaldi@ics.uci.edu
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Project description:Proteins in food and personal care products can pose a risk for an immediate immunoglobulin E (IgE)-mediated allergic response. Bioinformatic tools can assist to predict and investigate the allergenic potential of proteins. Here we present AllerCatPro 2.0, a web server that can be used to predict protein allergenicity potential with better accuracy than other computational methods and new features that help assessors making informed decisions. AllerCatPro 2.0 predicts the similarity between input proteins using both their amino acid sequences and predicted 3D structures towards the most comprehensive datasets of reliable proteins associated with allergenicity. These datasets currently include 4979 protein allergens, 162 low allergenic proteins, and 165 autoimmune allergens with manual expert curation from the databases of WHO/International Union of Immunological Societies (IUIS), Comprehensive Protein Allergen Resource (COMPARE), Food Allergy Research and Resource Program (FARRP), UniProtKB and Allergome. Various examples of profilins, autoimmune allergens, low allergenic proteins, very large proteins, and nucleotide input sequences showcase the utility of AllerCatPro 2.0 for predicting protein allergenicity potential. The AllerCatPro 2.0 web server is freely accessible at https://allercatpro.bii.a-star.edu.sg.
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Project description:Despite a high similarity with homologous protein families, only few proteins trigger an allergic immune response with characteristic TH2 polarization. This puzzling observation is illustrated by the major birch pollen allergen Bet v 1a and its hypoallergenic protein isoforms, e.g., Bet v 1d. Given the key role of proteolytic processing in antigen presentation and T cell polarization, we investigated the recognition of Bet v 1 isoforms by the relevant protease cathepsin S. We found that at moderately acidic pH values Bet v 1a bound to cathepsin S with significantly lower affinity and was more slowly cleaved than its hypoallergenic isoform Bet v 1d. Only at pH values ≤ 4.5 the known proteolytic cleavage sites in Bet v 1a became accessible, resulting in a strong increase in affinity towards cathepsin S. Antigen processing and class II MHC loading occurs at moderately acidic compartments where processing of Bet v 1a and Bet v 1d differs distinctly. This difference translates into low and high density class II MHC loading and subsequently in TH2 and TH1 polarization, respectively.
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Project description:In this study, the differences in effects of (-)-epigallocatechin gallate (EGCG) and proanthocyanidins (PC) on the functionality and allergenicity of soybean protein isolate (SPI) were studied. SDS-PAGE demonstrated that SPI-PC conjugates exhibited more high-molecular-weight polymers (>180 kDa) than SPI-EGCG conjugates. Structural analysis showed that SPI-PC conjugates exhibited more disordered structures and protein-unfolding, improving the accessibility of PC to modify SPI, compared to SPI-EGCG conjugates. LC/MS-MS demonstrated that PC caused more modification of SPI and major soybean allergens than EGCG, resulting in a lower abundance of epitopes. The successful attachment of EGCG and PC to SPI significantly increased antioxidant capacity in conjugates. Furthermore, SPI-PC conjugates exhibited greater emulsifying activity and lower immunoglobulin E (IgE) binding capacity than SPI-EGCG conjugates, which was attributed to more disordered structure and protein-unfolding in SPI-PC conjugates. It is implied that proanthocyanidins may be promising compounds to interact with soybean proteins to produce functional and hypoallergenic foods.
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