Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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The cashew allergens : a molecular and serological characterization
Reitsma, Marit - \ 2017
Wageningen University. Promotor(en): Harry Wichers; Huub Savelkoul, co-promotor(en): N.W. De Jong. - Wageningen : Wageningen University - ISBN 9789463430784 - 186
anacardium occidentale - allergens - serological surveys - protein transport - molecular detection - small intestine - pichia pastoris - in vivo experimentation - sds-page - western blotting - electrophoresis - allergenen - serologische overzichten - eiwittransport - moleculaire detectie - dunne darm - in vivo experimenten - elektroforese

Cashew nut allergy can be a severe food allergy of which the prevalence appears to be increasing. The aim of this thesis was a comprehensive molecular and serological characterisation of the cashew nut allergens Ana o 1, 2 and 3 for improved diagnosis and characterisation of patient populations.

Chapter 1 in this thesis provides background information on cashew nuts, allergy, the allergens Ana o 1, 2 and 3, the effect of heat treatments on cashew nut proteins, the digestibility of cashew nut proteins, cross-reactivity between cashew nut proteins and other tree nuts, and the detection of cashew nut in food products. Subsequently, in Chapter 2, a review is presented on the topic of epithelial protein and allergen transport. This review describes multiple pathways of intestinal protein transport, sums up existing experimental data concerning protein and peptide transport, and presents different methods to study this. Interestingly, the pathway of (allergenic) protein transport can differ between sensitized and non-sensitized persons. In sensitized persons, protein transport occurs transcellularly via enterocytes, and paracellularly with the involvement of mast cells, while in non-sensitized persons microfold cells and enterocytes are considered most important.

In the next three chapters, cashew nut allergens were studied. Cashew nut allergy and cashew nut allergens were chosen because of a high number of undiagnosed cashew nut allergic children reported at the children’s hospital “Kinderhaven”, in Rotterdam, an outpatient clinic that is involved in this study. Chapter 3 describes a protocol for the purification of Ana o 1, 2 and 3 from cashew nuts. Ana o 1 and 3 were purified by protein extraction, salt precipitation and filtering over a 30kDa molecular weight membrane. Ana o 2 was purified by protein extraction followed by gel filtration chromatography. These purified proteins were characterised by SDS-PAGE, western blot, glycoprotein stain, and protein identification. In this chapter also more in-depth analysis was performed on the N- and C-termini of the large and small subunits of Ana o 3. These N- and C-termini of Ana o 3, as well as the SDS-PAGE protein profiles were compared between cashew nuts of different origins in Chapter 4. In this chapter also the effects of different heat treatments on the electrophoretic behaviour of cashew nut allergens from various origins were studied, using both 1D and 2D electrophoresis. In these data no significant differences were detected between the electrophoresis patterns of Ana o 1, 2 or 3 in the various origins of cashew nuts. Some small but significant differences in Ana o 1, 2 and 3 content, however, were detected between the differently heated cashew nuts. No major differences in N- and C-terminal micro-heterogeneity were detected between cashew nuts of different origins.

Next, in Chapter 5, the cashew nut allergens Ana o 1, 2 and 3 were produced as recombinant proteins using a yeast (P. pastoris) production system. This procedure was used as recombinant allergens often produce higher yields of higher purity compared to native purified allergens. The recombinant proteins were compared to the native cashew nut proteins for their glycosylation pattern, IgE binding capacity, and 2D electrophoresis profile. In Chapter 6, the major findings of this thesis are discussed. An overview of the protein characteristics (e.g. 1D and 2D electrophoresis profile, glycosylation, IgE binding, pepsin-digestibility) was provided, as well as a discussion on the clinical benefits that can be derived from the results obtained in this thesis. Also some additional results are presented, studying the serologic cross-reactivity between cashew nuts and other tree nuts and Anacardiaceae nuts and fruits.

This thesis provides an in-depth study regarding the protein characteristics of the cashew nut allergens Ana o 1, 2 and 3. Using the allergens that were purified in this thesis project, the serum IgE levels of Ana o 1, 2 and 3 could be measured in cashew nut-allergic children. The allergens were also recombinantly produced to obtain higher quantity of allergens for regular use in diagnostics of cashew nut allergy. The results from this thesis can potentially expand clinical patient characterisation with measurements of IgE levels to purified and recombinantly produced major cashew nut allergens. These results might have applications for other food allergens or patient populations.

Extensive dry heating-induced changes in physicochemical and immunological properties of whey proteins
Liu, Fahui - \ 2016
Wageningen University. Promotor(en): Tiny van Boekel; Jan Wichers, co-promotor(en): Kasper Hettinga; Gosia Teodorowicz. - Wageningen : Wageningen University - ISBN 9789463430012 - 146
whey protein - heating - physicochemical properties - immune tolerance - antibodies - allergens - wei-eiwit - verwarming - fysicochemische eigenschappen - immunotolerantie - antilichamen - allergenen

Baked milk products, e.g. milk-protein containing muffins or baked cheese, can be tolerated by most cow’s milk allergic subjects. These products were also reported to contribute to the development of immune tolerance in allergic subjects. The main objective of this thesis was to investigate the effects of heating under dry conditions on the physicochemical and immunological properties of whey proteins. A simplified heating model, consisting of whey proteins and lactose, was used to reproduce baking conditions. Most of the Maillard reaction sites were found to be located in the reported conformational epitopes on whey proteins. Therefore, the structural changes subsequently resulted in a decreased IgG-binding capacity. The binding of glycation products to the receptor of AGE (RAGE) increased with heating time. Next, the formation of AGEs was further studied. Formation of sRAGE-binding ligands depended on the aggregation, “pH”, and aw of the samples. Moreover, the sRAGE-binding activity of the samples after digestion was changed and correlated with the digestibility of samples. Based on these results, a correlation between the formation of AGEs and their immunogenicity was hypothesized. Thus, the macrophage immunogenicity of glycated BLG was furtherly studied. The IgE-binding capacity of glycated samples and their influence on the polarization and gene expression of macrophages were studied in vitro. Glycation of BLG was found to reduce the expression of pro-inflammatory TNF-α, and increase the expression of anti-inflammatory TGF-β in M1 and M2 macrophages. The immunomodulatory potential of glycated BLG was further studied, as described. The uptake of glycated BLG by dendritic cells (DCs) was studied. Results showed that glycated BLG inhibited the degranulation of basophils in a dose-dependent manner. Glycation of BLG enhanced its uptake by DCs. However, the degradation of glycated BLG was faster than unheated BLG, indicating a retarded allergen-presentation efficiency of glycated BLG by DCs.

In conclusion, this thesis showed that extensive dry heating induces profound and specific effects on the physicochemical and immunological properties of whey proteins. Conditions during heating, such as aw and “pH”, affect the consequences of heating on whey proteins and their subsequent functions in interacting with immune cells. Compared to unheated and nonglycated samples, glycated BLG can be more efficiently taken up and degraded by DCs. In addition, glycation confers immunomodulatory properties on whey proteins, as tested in macrophages. These results might have consequences for preparing extensively dry heated allergens that can be used in oral immunotherapy. The data in this thesis also provided a better understanding on the mechanism underlying the observation that the development of immune tolerance can be accelerated by baked milk.

Proficiency test for allergens in food 2014
Bremer, M.G.E.G. ; Alamenou, P. ; Elbers, I.J.W. - \ 2015
Wageningen : RIKILT Wageningen UR (RIKILT report 2015.002) - 38
graansoorten - zuigelingenvoedsel - allergenen - voedselallergieën - laboratoriumproeven - tests - cereals - infant foods - allergens - food allergies - laboratory tests
In the autumn of 2014 a proficiency test for allergens in baby cereal was organized by RIKILT, Wageningen UR. This PT-test enabled laboratories to evaluate their competence for the analysis of allergens in baby cereal. Both quantitative and qualitative methods were accepted. The proficiency test was carried out according to ISO/IEC 17043, however this specific test is not part of the accreditation.
Surface functionalization and analysis thereof by ambient mass spectrometry
Manova, R.K. - \ 2014
Wageningen University. Promotor(en): Han Zuilhof, co-promotor(en): Teris van Beek. - Wageningen : Wageningen University - ISBN 9789462571570 - 214
biosensoren - detectie - biomarkers - allergenen - oppervlaktechemie - analytische methoden - synthese - unimoleculaire films - biosensors - detection - allergens - surface chemistry - analytical methods - synthesis - unimolecular films

A challenge in the global healthcare is the lack of suitable diagnostic tools for early disease detection. One possible solution is the use of biosensors in diagnostic tests. By definition, a biosensor is a bioanalytical device that detects the presence of a compound (analyte) in the sample. The detection relies on the specific interactions between the ligands that are attached onto the biosensor surface and the analytes in the sample.

This PhD dissertation is focused on developing an optimal protocol for attachment of ligands onto the biosensing surface. A step-wise approach was established for the versatile and reproducible modification and functionalization of a silicon nitride-based biosensor. This approach included the application of bioorthogonal copper-free reactions as a useful tool for oriented attachment of biomolecules. Additionally, a novel surface sensitive analytical method was developed for the identification of covalently bound molecules in monolayers. The method, which is fast and easy to apply, uses DART ionization coupled to a high-resolution mass spectrometer. The nm-thin layers were analysed, and interpretation rules for the obtained mass spectra were formulated. The method was applied in the identification of commercially available nm-thin coatings and biochips.

Culicoides obsoletus allergens for diagnosis of insect bite hypersensitivity in horses
Meide, N.M.A. van der - \ 2013
Wageningen University. Promotor(en): Huub Savelkoul, co-promotor(en): Edwin Tijhaar. - S.l. : s.n. - ISBN 9789461736697 - 228
paarden - equus - culicoides obsoletus - insectenbeten - allergenen - overgevoeligheid - allergieën - cytokinen - diagnose - elisa - vectoren, ziekten - immunologie - horses - insect bites - allergens - hypersensitivity - allergies - cytokines - diagnosis - disease vectors - immunology

AInsect Bite Hypersensitivity (IBH) is the most common skin allergy in horses and involves a Type I (IgE mediated) hypersensitivity reaction against bites of insects, mainly of the Culicoides species. Welfare of affected horses is seriously reduced and no fully curative treatment is yet available. Furthermore, current diagnostic tests are unreliable because of their low sensitivity and specificity. Aim of our research was to increase the understanding of immunological aspects of IBH, with special attention to improving diagnosis by the characterization and production of recombinant allergens.

Whole body extracts (WBE) of three Culicoides species: C. obsoletus C. nubeculosus and C. sonorensis were evaluated for their applicability for diagnosis of IBH in horses in The Netherlands. They were tested for IgE binding by ELISA and Western blotting and for their capacity to degranulate basophils in a histamine release test. For all tests, best results were obtained with C. obsoletus. The ELISA was further evaluated using C. obsoletus extract on approximately 200 IBH affected and healthy horses, which demonstrated high test sensitivity and specificity. C. obsoletus-specific IgE serum levels were found to be the same in the IBH season and off season, suggesting that the test can be used to diagnose horses in winter when clincial symptoms are absent.

Since C. obsoletus was found to be the most important species for diagnosis of IBH in The Netherlands, mRNA of this Culicoides species was sequenced and assembled to create a transcriptome. Using the sequences from in literature described allergens from C. nubeculosus and C. sonorensis, similarity searches were performed on this transcriptome,. This resulted in the identification of seven allergens from C. obsoletus. These allergens were cloned and expressed as recombinant proteins in E. coli and named Cul o 1 – Cul o 7. The frequency of positive test results by ELISA within IBH affected horses ranged from 38 % to 67 %. The capability of the allergens to induce Type I hypersensitivity reaction in IBH affected horses was demonstrated by an intradermal test.

The applicability of the 7 C. obsoletus derived recombinant allergens was further evaluated and compared with C. obsoletus WBE in an IgE ELISA using a large number of horses.The highest test accuracy was obtained with WBE, followed by Cul o 2, 3 and 5. Two ELISA’s with a combination of recombinant allergens, combi-1 (Cul o 3, 5 and 7) and combi-2 (Cul o 1, 2, 5 and 7) were additionally performed and both resulted in high test accuracies close to that obtained with WBE. Both combi-1 and combi-2 resulted in a lower test sensitivity with samples collected in winter compared to samples collected in IBH season, but most IBH affected horses could still also be correctly diagnosed in winter.

The association between several factors and IgE levels against C. obsoletus whole body extract and the 7 recombinant allergens was quantified. Furthermore, the relation between IgE levels and severity of symptoms was examined. Severity of symptoms and IgE levels against several C. obsoletus allergens were found to be related. Factors that were found to be associated with IgE levels were: breed, age, month of scoring, interaction between IBH status and month of scoring, degree of itchiness and number of seasons horses were affected with IBH.

The general discussion discussed the prospects to use the produced recombinant allergens for immunotherapy treatment of IBH affected horses. The panel of all 7 recombinant allergens allows to determine for which exact components of C. obsoletus the IBH horses are allergic (“component resolved diagnosis”). This will enable a tailor made composition of (recombinant) allergens for use in immunotherapy.

Protein analysis in food by mass spectrometr: an overview
Nessen, M.A. ; Hooijerink, H. ; Bremer, M.G.E.G. ; Manti, V. ; Voorhuijzen, M.M. ; Dijk, J.P. van; Wubs, K.L. ; Blokland, M.H. ; Sterk, S.S. - \ 2012
eiwitanalyse - massaspectrometrie - allergenen - eiwitten - protein analysis - mass spectrometry - allergens - proteins
Poster met informatie over eiwitanalyse in voedsel door middel van massaspectrometrie.
Multidisciplinary Approaches to Allergies
Gao Zhongshan, ; Shen, Hua-Hao ; Zheng, M. ; Frewer, L.J. ; Gilissen, L.J.W.J. - \ 2012
Berlin : Springer (Advanced topics in science and technology in China ) - ISBN 9783642316081 - 480
allergieën - allergenen - diagnose - therapie - preventie - etiologie - allergies - allergens - diagnosis - therapy - prevention - aetiology
Allergy is an immunological disease caused by multiple factors and characterized by variability, specificity and complexity. "Multidisciplinary Approaches to Allergies" covers diverse aspects ranging from basic molecular mechanisms to societal issues within the framework of multidisciplinary approaches to allergies. It contains 29 chapters in 6 parts: General Allergy; Allergenic Sources and Allergens; Diagnosis; Therapies and Pharmacy; Hypoallergenic Products; Environment, Hygiene and Societal Issues.
Nanoweegschaal voor gluten
Beek, T.A. van - \ 2011
Kennis Online 8 (2011)dec. - p. 8 - 8.
voedseltechnologie - nanotechnologie - gluten - tests - gezondheid - allergenen - food technology - nanotechnology - health - allergens
Wageningse chemici werken aan de ontwikkeling van een minuscule weegschaal op een chip. Mocht hij de verwachtingen waarmaken, dan kan de nanoweegschaal kleine hoeveelheden allergenen in voedsel meten, en misschien ook stoffen in het bloed die in een vroeg stadium auto-immuunziektes verraden.
De meeste vragen gaan over E-nummers en voedselallergie
Hartemink, R. - \ 2010
Over gevoelig heden : kwartaalblad van de Stichting Voedselallergie 26 (2010)1. - ISSN 0928-9127 - p. 16 - 17.
voedselallergieën - allergenen - vragenlijsten - voeding en gezondheid - etiketteren van voedingsmiddelen - voedingsinformatie - food allergies - allergens - questionnaires - nutrition and health - nutrition labeling - nutrition information
De informatiesite begon heel bescheiden in 1999 als een simpele vraag-antwoordlijst met circa dertig vragen over voeding op de server van de Wageningse universiteit. Inmiddels is het een uitgebreide site in 27 talen, die meer dan 300 duizend bezoekers per maand trekt. De website geeft informatie over de productiewijze van voeding, ingrediënten en additieven (E-nummers), voedselveiligheid en allergenen. Een blik achter de schermen.
Chemical and Biological Properties of Food Allergens
Jedrychowski, L. ; Wichers, H.J. - \ 2009
Boca Raton : CRC Press (Chemical and functional properties of food components ) - ISBN 9781420058550 - 447
voedselallergieën - allergenen - voedsel - overgevoeligheid - food allergies - allergens - food - hypersensitivity
This book provides epidemiological data on food allergens and information on the incidence of food allergies. It discusses the link between hypersensitivity and immune system health and covers methods used for assays on allergenic components, animal models for allergen analysis, and clinical methods for diagnosis. Furthermore, it highlights future trends in applying recombinant food allergens.
Stability of the Bet v 1 cross-reactive allergens Api g 1 and Dau c 1 : a biophysical approach
Bollen, M.A. - \ 2009
Wageningen University. Promotor(en): Tiny van Boekel; Huub Savelkoul; Harry Wichers, co-promotor(en): Hans Helsper. - [S.l.] : S.n. - ISBN 9789085853763 - 160
allergenen - voedselallergieën - kruisreactie - betula - daucus carota - penen - selderij - apium graveolens - hooikoorts - allergens - food allergies - cross reaction - carrots - celery - pollen allergy
The allergen Bet v 1 is known as the primary sensitizer for birch pollen-related food allergy and is responsible for IgE cross-reactivity to pathogenesis-related 10 (PR-10) proteins from, in particular, fruits from the Rosaceae and vegetables from the Apiaceae families. The allergenic potential of PR-10 proteins is mainly characterized for specific recombinantly produced isoforms, which are used for research and diagnostic purposes. However, in natural food sources these allergens are often present as isoform mixtures. The first aim of this research was to purify and characterize PR-10 allergens as natural isoform mixtures to determine whether differences could be observed between natural and recombinant allergens and between plant families. The second aim was to find a relationship between the physico-chemical stability of PR-10 proteins and structural characteristics to explain differences in IgE binding potential and cross-reactivity. The PR-10 allergens Bet v 1 from birch, Api g 1 from celery, and Dau c 1 from carrot were purified under mild conditions following a standardized protocol. Different allergen isoforms were determined and circular dichorism (CD) analyses of the allergen mixtures showed a similar secondary structure composition as observed for other PR-10 proteins. The allergen mixtures and recombinant allergens were characterized by stability studies to pH, temperature and denaturant where CD was used to detect structural changes. Minor differences were observed in stability between natural isoform mixtures and between the recombinant isoforms, although recombinant Dau c 1 was likely destabilized by its attached His-tag. A general trend was observed for allergen stability, structural differences and their relationship to the IgE binding capacity in aqueous solutions. The allergenic potential decreases in the following order: Bet v 1, the primary allergen of birch pollen-related allergies, Mal d 1, Api g 1 and Dau c 1, in accordance with their amino acid sequence identity. Bet v 1 cross-reactive IgE antibodies preferably bind to the charged and polar residues of Mal d 1 for which the positive charge can be increased by the physiological pH of fruit. Api g 1 appears to be more stable than Dau c 1 as the result of a tighter hydrophobic packing. However, the thermodynamic stability of Api g 1 is similar to that of Bet v 1, but the higher proportion of hydrophobic residues and the reduced proportion of charged residues are responsible for the lower IgE binding capacity. Furthermore, the IgE binding capacity is not severely affected, as long as the protein is able to refold. The implications of these findings are discussed in the context of the development of allergic symptoms upon exposure to these PR-10 proteins.

Allergische consument is tevreden met Santana
Maas, M.P. van der; Schenk, M.F. - \ 2008
Over gevoelig heden : kwartaalblad van de Stichting Voedselallergie 24 (2008)4. - ISSN 0928-9127 - p. 9 - 11.
voedselallergieën - allergenen - appels - veredelde rassen - voedselintolerantie - stoornissen samenhangend met voedsel - voeding en gezondheid - consumenten - food allergies - allergens - apples - improved varieties - food intolerance - food-related disorders - nutrition and health - consumers
Nederland had twee jaar geleden de primeur: Santana, een hyperallergeen appelras voor mensen met appelallergie. Wageningen UR heeft de ervaringen van de consumenten over 2006 en 2007 onderzocht. De vermindering van de allergische reactie is ongeveer volgens verwachting en de tevredenheid blijkt hoog te zijn
Klant wil duidelijker etiket : Onderzoek naar voorkeur voedselallergische consument voor etikettering
Voordouw, J. ; Cornelisse-Vermaat, J.R. - \ 2008
Over gevoelig heden : kwartaalblad van de Stichting Voedselallergie 24 (2008)1. - ISSN 0928-9127 - p. 4 - 6.
voedselallergieën - consumenten - etiketteren van voedingsmiddelen - voeding en gezondheid - stoornissen samenhangend met voedsel - allergenen - food allergies - consumers - nutrition labeling - nutrition and health - food-related disorders - allergens
De voedselallergische consument is niet tevreden over de informatie op het etiket en wenst een zo volledig mogelijke ingrediëntenlijst. Dat blijkt uit een studie van de Wageningse onderzoekers Judith Cornelisse- Vermaat en Jantine Voordouw in samenwerking met Griekse collega's. Dit artikel is een bewerking van de lezing van Judith Cornelisse tijdens de Nationale Voedselallergiedag november 2010.
Birch pollen allergy: molecular characterization and hypoallergenic products
Schenk, M.F. - \ 2008
Wageningen University. Promotor(en): Evert Jacobsen; Lynn Frewer, co-promotor(en): Rene Smulders; Luud Gilissen. - [S.l.] : S.n. - ISBN 9789085048732 - 192
betula - allergieën - allergenen - appels - voedselallergieën - diëten - transgene planten - houding van consumenten - cultivars - plantenveredeling - selectie - ige - dna-sequencing - genetische variatie - hooikoorts - moleculaire veredeling - allergies - allergens - apples - food allergies - diets - transgenic plants - consumer attitudes - plant breeding - selection - dna sequencing - genetic variation - pollen allergy - molecular breeding
Allergic diseases, such as hay fever and food allergy, affect a substantial part of the population in westernized countries. Pollen of the European white birch (Betula pendula) is a considerable cause of hay fever (seasonal allergic rhinitis) in northern and central Europe. The major birch pollen allergen is Bet ν 1, which is the conventional allergen name for the birch pollen proteins of a large group of proteins otherwise known as PR-10 proteins. Individuals that suffer from birch pollen allergy are particularly prone to develop Oral Allergy Syndrome (OAS) due to the occurrence of an IgE-mediated cross-reaction between Bet ν 1 and PR-10 proteins in various plant foods. The high prevalence of apple allergy among hay fever sufferers is a good example of OAS. Allergic diseases can be severe for patients and have considerable medical and economical costs as well. Consequently, prevention of birch pollen allergy and OAS would contribute to an improvement of the quality of life of many patients. This thesis examines the feasibility of strategies that are directed towards development of hypoallergenic (= having a reduced allergenicity) birch trees or plant foods in order to alleviate Bet ν 1 [PR-10]- associated complaints.
When the development of hypoallergenic products involves application of genetic modification (GM), societal concerns about this technology should be taken into account. The attitude towards hypoallergenic products developed by GM was examined in the survey that is described in Chapter 2. This study differentiated between patients and non-patients. Attitude towards GM was measured for two applications directed against hay fever (hypoallergenic birch and grass) and one application directed against food allergy (hypoallergenic apple). Attitude was described in terms of two constructs that were labelled as 'benefits' and 'rejection factors'. Hay fever sufferers perceived greater 'benefits' associated with application of GM to develop hypoallergenic birch trees as compared to non-sufferers. The perceived 'benefits' increased with a higher self-reported impact of hay fever on quality of life. No attitudinal differences were observed between sufferers and non-sufferers for the attitudinal construct 'rejection factors'. Furthermore, the impact of perceived 'benefits' on acceptance of GM was larger than the impact of 'rejection factors'.
The perceptions of 'benefits' were further explored in Chapter 3. Here, the attitude towards hypoallergenic apples was examined in a survey in which consumers rate a set of apple profiles that varied in the breeding method that was applied during development (GM vs. traditional breeding), in pesticide usage, and in the degree of allergenicity. Acceptance of hypoallergenic apples was high among all consumers, also when GM was involved in their development. Acceptance of hypoallergenic products was higher among consumers with an apple allergy, presumably because they find a personal 'benefit' associated with these products. Novel GM products that are recognised as beneficial by some consumers may consequently experience an increased acceptance. However, both Chapter 2 and 3 indicated a clear consumer preference for
traditional breeding over breeding by GM for the development of hypoallergenic birch trees or food products. Approaches which focus on traditional breeding should thus be explored first.
Chapter 3 also evaluated appreciation of the hypoallergenic apple cultivar Santana, which was introduced in shops in a large-scale sales pilot labelled as 'suitable for individuals suffering from mild apple allergy' in 2006. A survey among consumers that bought the Santana measured the self-reported response to this apple. Almost half (42%) of the apple allergic consumers had no allergic reaction at all after eating the Santana. Most (96%) consumers who did experience an allergic reaction reported the symptoms as minor. The self-reported severity of the apple allergy, the occurrence of other fruit allergies, and age were associated with the occurrence of an allergic reaction to the Santana. Overall, the Santana was valued positively by the majority of apple allergic consumers, regardless of whether these consumers could eat the apple without experiencing an allergic reaction. Development of hypoallergenic foods such as Santana may therefore contribute to food allergy management, although variation among individual consumers in the allergic response to hypoallergenic products should be taken into account when developing and marketing such products.
A prerequisite for designing strategies for selection and breeding of hypoallergenic birch trees is knowledge on diversity of Bet ν 1 genes and on allergenicity of the protein variants (=isoforms) that are encoded by these genes. Chapter 4 describes a study on the variation of Bet ν 1 isoforms in .the most common birch species in Europe, Betula pendula. PR-10 sequences from three B. pendula cultivars were amplified, cloned and sequenced. Forty-four unique PR-10 sequences were recovered from B. pendula and these were assigned to thirteen putative genes based on sequence identity and intron length. Information on gene transcription was inferred from a comparison with existing mRNA sequences and suggested that seven of these genes are transcribed in pollen. Bet ν 1 isoforms are known to vary in IgE-reactivity. The study in Chapter 4 showed that isoforms with high and low IgE-reactivity are encoded by different genes. Thus, one birch pollen grain has the genetic background to produce a mixture of isoforms with varying IgE-reactivity. The sequence of one of the isoforms with a high IgE-reactivity was present in all examined B. pendula trees. The search for hypoallergenic birch trees was, therefore, expanded to other Betula species.
The selection of a representative set of species which cover variation among Betula species requires knowledge on phylogenetic relationships within the genus Betula. Chapter 5 describes a study on the reconstruction of the phylogeny of this genus using multilocus data from AFLP markers. The taxonomy of the genus Betula is complicated by the occurrence of parallel evolution of morphological traits, of polyploidisation events, and of extensive hybridisation among species. A large number of polymorphic AFLP markers (321 variable bands) were produced in 107 Betula accessions from 23 species and 11 hybrids. The analysis identified four distinct groups within the
genus. These groups are partly in disagreement with the traditional, but disputed, division of the genus. The majority of the species and all hybrids fell within subgenus Betula and are thus closely related to B. pendula. Subgenus Chamaebetula and part of the Neurobetula species should be merged with subgenus Betula. Apart from subgenus Betula, the subgenera Betulenta, Betulaster, and the remaining part of Neurobetula formed distinct and well-supported groups and should thus be maintained. The results from the AFLP study are to a large extent congruent with results from previous studies that made use of molecular (sequence) data.
The allergenic potency of Betula species other than B. pendula is described in Chapter 6 in which the PR-10 genes from eight birch species are cloned and sequenced. These species represent the various groups that were previously identified in the genus Betula. In total, 134 unique PR-10 sequences were recovered, including both sequences with a full open reading frame and pseudogenes. Sequences were attributed to putative genes, which could, in turn, be subdivided into seven subfamilies. Five subfamilies were common to all birch species. Q-TOF LC-MSE was applied to detect peptide fragments of Bet ν 1 that are unique for particular isoforms, in order to identify which PR-10 genes are expressed in pollen. The relative abundance of individual isoforms in the pollen proteome was also determined by Q-TOF LC-MSE. Each of the five examined birch species expressed a mixture of isoforms with at least 4-5 different isoforms. Both isoforms with a high and low IgE-reactivity were abundant in the Bet ν 1 mixture of B. pendula. The other birch species lacked Bet ν 1 isoforms that are similar to known isoforms with a low IgE-reactivity, but isoforms that are similar to known isoforms with a high IgE-reactivity were abundant in all species except B. lenta.
In Chapter 7, the antigenic and allergenic profiles of pollen extracts from twenty-four different birch trees were determined by SDS-PAGE and Western blotting. Fifteen different Betula species were examined, covering all previously identified subgenera/groups in the genus Betula. The major birch allergen Bet ν 1 was an abundant protein in all examined pollen extracts. Immune-reactivity of the extracts was tested using a pool of sera that were obtained from birch pollen allergic patients. A strong 17 kDa band, representing Bet ν 1, was recognized by the serum pool in all pollen extracts. The degree of immune-reactivity correlated well with the total amount of Bet ν 1 in the extract, which varied from 44% to 61% of the total protein content. Pollen extracts from different birch trees varied in the total protein content, presumably the result of variation in pollen quality due to pollen rupture and varying hydration during the extraction. Bet ν 1 isoforms in the pollen of eleven Betula species were subsequently digested with trypsin and the resulting fragments were analyzed and quantified by Q-TOF LC-MSE. Peptides that contained amino acid residues that are associated with high IgE-reactivity were detected in all examined species, and were abundant as well. Differences between Betula species in the relative presence of these amino acid residues were small. As a consequence, differences in allergenicity between birch trees
are probably far too small to have clinical relevance, implying that all examined Betula species will be highly allergenic.
The research presented here did not identify any birch trees in which Bet ν 1 variants with a high IgE-reactivity are reduced in abundance or are absent. Development of hypoallergenic birch trees thus must rely on other approaches, such as selection or introduction of male sterility (trees that do not produce male catkins were observed during the study), or the application of RNAi to silence the Bet ν 1 genes in pollen. Also, the conducted research showed that acceptance of hypoallergenic GM products is quite high, particularly for allergic sufferers who were allergic to the product being modified. This supports the hypothesis that consumer attitude towards GM is partly driven by recognition of specific and personally relevant benefits. The hypoallergenic apple cultivar Santana, which was developed by selection and not by GM, was well received by allergic consumers, indicating that there is a market for hypoallergenic products.

Succes- en faalfactoren voor vermarkten van biologische allergeenvrije producten : deelonderzoek 1 van het project 'Verwaarding productkwaliteit betreffende gezondheid en allergie'
Jukema, N.J. ; Leeuwen, M.A.E. van - \ 2008
Lelystad : PPO AGV (Rapport /PPO-AGV 3250090400) - 38
biologische landbouw - biologische voedingsmiddelen - allergenen - gluten - glutenvrije diëten - appels - consumentengedrag - marketing van voedingsmiddelen - landbouwplantenteelt - akkerbouw - voeding en gezondheid - keuzegedrag - eragrostis tef - organic farming - organic foods - allergens - gluten free diets - apples - consumer behaviour - food marketing - crop husbandry - arable farming - nutrition and health - choice behaviour
In dit onderzoek is achterhaald wat de perspectieven voor de biologische sector zijn om in te spelen op de markt van allergeenvrije producten. Het doel van het onderzoek is het bepalen van succes- en faalfactoren van het vermarkten van biologische allergeenvrije dieetproducten op basis van een gezondheidsvoordeel. Het onderzoek is tot stand gekomen op basis van de bevindingen van literatuuronderzoek over de bruikbaarheid van claims rond de positieve effecten van gezondheidsbevorderende inhoudstoffen van biologische producten als marketingtool. Door telefonische interviews zijn in samenwerking met de sector voorbeelden van marktintroducties van allergeenvrije producten verder uitgediept. In dit onderzoek zijn twee praktijkvoorbeelden nader onder de loep genomen: de (biologische) allergeenvrije Santana-appel en de glutenvrije Teff. Aan de hand van deze praktijkvoorbeelden en de theorie over keuzegedrag van consumenten rondom voeding, zijn de belangrijkste geleerde lessen met betrekking tot de afzet en marketing van biologische dieetvoeding richting consument gedestilleerd.
Allergie voor dieren : inventarisatie over het voorkomen van allergische reacties bij de mens als gevolg blootstelling aan dierlijke allergenen
Terreehorst, I. ; Willemse, T. ; Heederik, D.J.J. ; Zee, J.S. van der; Groot, H. de; Savelkoul, H.F.J. ; Kerkhoffs, M. ; Wolf, I.D. de - \ 2007
Den Haag : Raad voor Dierenaangelegenheden - 76
dierhouderij - gezelschapsdieren - insecten - allergieën - allergenen - overgevoeligheid - literatuuroverzichten - hobbydieren - mens-dier relaties - animal husbandry - pets - insects - allergies - allergens - hypersensitivity - literature reviews - hobby animals - human-animal relationships
Op grond van een literatuuronderzoek is een top-10 van allergieën voor dieren in Nederland opgesteld
Proefverkoop hypoallergene Santana bij Albert Heijn
Maas, M.P. van der - \ 2007
voedselallergieën - appels - allergenen - veredelde rassen - marketing voor de detailhandel - marketing - food allergies - apples - allergens - improved varieties - retail marketing
PPO Fruit heeft samen met de Stichting Voedselallergie een protocol ontwikkeld om Santana als hypoallergeen product juridisch, medisch en ketentechnisch verantwoord op de markt te brengen.
Protein quaternary structure and aggregation in relation to allergenicity
Boxtel, E.L. van - \ 2007
Wageningen University. Promotor(en): Harry Gruppen, co-promotor(en): Ben van den Broek; S.J. Koppelman. - [S.l.] : S.n. - ISBN 9789085047827 - 152
allergenen - eiwitten - denaturatie - chemische structuur - voedselallergieën - sojaeiwit - aardnoteneiwit - paranoten - eiwitvertering - allergens - proteins - denaturation - chemical structure - food allergies - soya protein - groundnut protein - Brazil nuts - protein digestion
In order to induce systemic food allergic reactions in humans, proteins after digestion in the human gastro-intestinal tract should still be able to bind IgE. The aim of the work presented in this thesis was to determine the effects of heating on the structure and digestibility of cupin and prolamin food allergens from peanuts, Brazil nuts and soybeans and to determine the effects of digestion on the IgE binding capacity of these allergens. Representative allergen preparations were purified prior to the investigations. To this end, a large-scale purification method was developed for the purification of Brazil nut allergen Ber e 1, comprising its complete isoform pool. The denaturation temperature of the latter allergen at the common pH values of foods (5-7) appeared to be very high. As a result, this protein is assumed not to be denatured during common food processing and to be digested (mainly) in its native form. The native form of Ber e 1 is known to have a high stability towards peptic digestion, which likely explains the allergenicity of this protein. The representative quaternary structure of vicilin allergen Ara h 1 from peanuts appeared to be an oligomeric structure, in which the protein is assumed to interact with proanthocyanidins via a specific distribution of proline residues on its surface. Heat-induced aggregation prior to peptic hydrolysis under in vitro conditions did not affect the digestibility of Ara h 1, whereas heat-induced aggregation of legumin allergens Ara h 3 from peanuts and glycinin from soybeans (slightly) decreased the digestion rates. Regardless of pre-heating, the IgE binding capacity of the latter allergens diminished fast during pepsin digestion. As a result, in terms of systemic food allergic reactions, legumin allergens from peanuts and soybeans might not be very important allergens. Vicilin allergen Ara h 1 could still bind IgE after prolonged peptic digestion. Two pepsin-resistant epitopes were deduced and indications for four additional pepsin-resistant epitopes are presented. These epitopes are all situated on the unique N-terminal part of the allergen, which might explain why allergic reactions to peanuts are often severe, compared to other legume allergies.
Managing allergens in food
Mills, C. ; Wichers, H.J. ; Hoffmann-Sommergruber, K. - \ 2007
Cambridge : Woodhead (Woodhead Publishing in food science, technology and nutrition ) - ISBN 9781845690281 - 336
allergenen - allergieën - voedsel - voedselverwerking - allergens - allergies - food - food processing
Controlling allergens in food is a matter of increasing importance for the food industry, especially in light of recent legislation. Effective handling of allergens depends on identifying allergenic ingredients, creating separate production lines for allergen-free products, and effective labelling to inform consumers about which products are safe to eat. Recent attention has also focused on novel methods to manage allergens in food, for example by reducing allergenicity through the prudent selection of raw food materials and improved processing techniques. Part 1 discusses the diagnosis of offending foods and how allergens can affect the quality of life. Expanding on these fundamentals, Part 2 reviews the effect of different methods of food processing on allergens and novel technologies which can reduce the potency of allergens or remove them altogether from foods. The final part of the book covers the key area of risk assessment and allergen management to achieve more uniform standards within the industry. Practical strategies to improve consumer acceptance of GM foods are also discussed.
Vergroot traceerbaarheid het vertrouwen?
Rijswijk, W. van; Cornelisse-Vermaat, J.R. ; Frewer, L.J. - \ 2006
Voedingsmiddelentechnologie 39 (2006)4. - ISSN 0042-7934 - p. 14 - 16.
houding van consumenten - consumenten - voedselveiligheid - voedselallergieën - EU regelingen - voedingsmiddelenwetgeving - etiketteren van voedingsmiddelen - informatietechnologie - allergenen - consumer attitudes - consumers - food safety - food allergies - EU regulations - food legislation - nutrition labeling - information technology - allergens
Vergroot traceerbaarheid het vertrouwen? Informatie moet bruikbaar zijn voor allergische consumenten EU-regelingen proberen het vertrouwen van consumenten in de kwaliteit en veiligheid van producten te verhogen. Bedrijven worden verplicht informatie over de herkomst van producten op het etiket te vermelden. Vooral consumenten met voedselallergieën zullen daarvan profiteren.
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