Clare Mills

Transcriptome analysis of grain development in hexaploid wheat

BackgroundHexaploid wheat is one of the most important cereal crops for human nutrition. Molecular understanding of the biology of the developing grain will assist the improvement of yield and quality traits for different environments. High quality transcriptomics is a powerful method to increase this understanding.ResultsThe transcriptome of developing caryopses from hexaploid wheat (Triticum aestivum, cv. Hereward) was determined using Affymetrix wheat GeneChip® oligonucleotide arrays which have probes for 55,052 transcripts. Of these, 14,550 showed significant differential regulation in the period between 6 and 42 days after anthesis (daa). Large changes in transcript abundance were observed which were categorised into distinct phases of differentiation (6–10 daa), grain fill (12–21 daa) and desiccation/maturation (28–42 daa) and were associated with specific tissues and processes. A similar experiment on developing caryopses grown with dry and/or hot environmental treatments was also analysed, using the profiles established in the first experiment to show that most environmental treatment effects on transcription were due to acceleration of development, but that a few transcripts were specifically affected. Transcript abundance profiles in both experiments for nine selected known and putative wheat transcription factors were independently confirmed by real time RT-PCR. These expression profiles confirm or extend our knowledge of the roles of the known transcription factors and suggest roles for the unknown ones.ConclusionThis transcriptome data will provide a valuable resource for molecular studies on wheat grain. It has been demonstrated how it can be used to distinguish general developmental shifts from specific effects of treatments on gene expression and to diagnose the probable tissue specificity and role of transcription factors.

In vitro digestion methods for assessing the effect of food structure on allergen breakdown

This article reviews the in vitro digestion models developed to assess the stability of food allergens during digestion. It is hypothesised that food allergens must exhibit sufficient gastro-intestinal stability to reach the intestinal mucosa where absorption and sensitisation (development of atopy) can occur. The investigation of stability of proteins within the gastrointestinal tract may provide prospective testing for allergenicity and could be a significant and valid parameter that distinguishes food allergens from nonallergens. Systematic evaluation of the stability of food allergens that are active via the gastrointestinal tract is currently tested in traditional pepsin digestibility models. The human gastrointestinal tract however is very complex and this article points out the importance of using physiologically relevant in vitro digestion systems for evaluating digestibility of allergens. This would involve the simulation of the stomach/small intestine environment (multi-phase models) with sequential addition of digestive enzymes, surfactants such as phospholipids and bile salts under physiological conditions, as well as the consideration of the effect of the food matrices on the allergen digestion.

Consensus Communication on Early Peanut Introduction and the Prevention of Peanut Allergy in High-risk Infants

The purpose of this brief communication is to highlight emerging evidence to existing guidelines regarding potential benefits of supporting early, rather than delayed, peanut introduction during the period of complementary food introduction in infants. This document should be considered as interim guidance based on consensus among the following organizations: American Academy of Allergy, Asthma & Immunology; American Academy of Pediatrics; American College of Allergy, Asthma & Immunology; Australasian Society of Clinical Immunology and Allergy; Canadian Society of Allergy and Clinical Immunology; European Academy of Allergy and Clinical Immunology; Israel Association of Allergy and Clinical Immunology; Japanese Society for Allergology; Society for Pediatric Dermatology; and World Allergy Organization. More formal guidelines regarding early-life, complementary feeding practices and the risk of allergy development will follow in the next year from the National Institute of Allergy and Infectious Diseases – sponsored Working Group and the European Academy of Allergy and Clinical Immunology.

Food processing increases casein resistance to simulated infant digestion.

The objective of this study was to determine whether processing could modify the resistance of casein (CN) to digestion in infants. A range of different dairy matrices was manufactured from raw milk in a pilot plant and subjected to in vitro digestion using an infant gut model. Digestion products were identified using MS and immunochemical techniques. Results obtained showed that CNs were able to resist digestion, particularly κ- and αs(2)-CN. Resistant areas were identified and corresponded to fragments hydrophobic at pH 3.0 (gastric conditions) and/or carrying post-translational modifications (phosphorylation and glycosylation). Milk processing led to differences in peptide patterns and heat treatment of milk tended to increase the number of peptides found in digested samples. This highlights the likely impact of milk processing on the allergenic potential of CNs.

A framework for measuring the social impact of food allergy across Europe: a Europrevall state of the art paper

This state of the art paper has been developed through EuroPrevall, a European multicentre research project funded by the European Union which aims to improve quality of life for food allergic individuals. Food allergy (whether clinically diagnosed or self‐perceived) represents a major health issue in Western societies and may have a considerably greater impact on society than was previously believed. However, the social impact of food allergy has never been systematically investigated using validated instruments. Combining the information from studies on health‐related quality of life (HRQoL) with epidemiological data on prevalence will ultimately give some indication of the magnitude of the social impact of food allergy in Europe. HRQoL can be assessed with disease‐specific questionnaires, which are being developed in EuroPrevall. These instruments will be used to identify HRQoL problems associated with food allergy, and to assess the effectiveness of interventions and to guide the development of regulatory policies.

Effect of Heating and Glycation on the Allergenicity of 2S Albumins (Ara h 2/6) from Peanut

Background Peanut allergy is one of the most common and severe food allergies, and processing is known to influence the allergenicity of peanut proteins. We aimed to establish the effect of heating and glycation on the IgE-binding properties and biological activity of 2S albumins (Ara h 2/6) from peanut. Methodology/Principal Findings Native Ara h 2/6 was purified from raw peanuts and heated in solution (15 min, 110°C) in the presence or absence of glucose. Ara h 2 and 6 were also purified from roasted peanut. Using PBMC and sera from peanut-allergic patients, the cellular proliferative potency and IgE reactivity (reverse EAST inhibition) and functionality (basophil degranulation capacity) of allergens were assessed. Heating Ara h 2/6 at 110°C resulted in extensive denaturation, hydrolysis and aggregation of the protein, whilst Ara h 2 and 6 isolated from roasted peanut retained its native conformation. Allergen stimulation of PBMC induced proliferation and Th2 cytokine secretion which was unaffected by thermal processing. Conversely, IgE reactivity and functionality of Ara h 2/6 was decreased by heating. Whilst heating-glycation further reduced the IgE binding capacity of the proteins, it moderated their loss of histamine releasing capacity. Ara h 2 and 6 purified from roasted peanut demonstrated the same IgE reactivity as unheated, native Ara h 2/6. Conclusions/Significance Although no effect of processing on T-cell reactivity was observed, heat induced denaturation reduced the IgE reactivity and subsequent functionality of Ara h 2/6. Conversely, Ara h 2 and 6 purified from roasted peanut retained the structure and IgE reactivity/functionality of the native protein which may explain the allergenic potency of this protein. Through detailed molecular study and allergenicity assessment approaches, this work then gives new insights into the effect of thermal processing on structure/allergenicity of peanut proteins.

A framework for measuring costs to society of IgE‐mediated food allergy

Both immunoglobulin E (IgE)‐mediated food allergy and food intolerance can lead to many changes in personal behaviour and health care resource use which have important economic consequences. These costs will impact directly, indirectly and intangibly on both individuals and society in general. It is important to measure the cost of illness (COI) of food allergy as a first step in developing and evaluating measures to reduce and control the burden of illness. This paper outlines a framework for assessing COI of food allergy from different viewpoints. It offers a structure for identifying the different cost impacts on allergic and nonallergic consumers, food producers and society as a whole, and for scoping, measurement and valuation of relevant costs. Within this structure, the existing literature is reviewed. This review illustrates the lack of information and clear methodology for assessing costs of food allergy. The paper concludes that there is a need for a more structured research programme to generate data essential for future evaluations of procedures and technologies for the diagnosis, treatment and management of food allergy.

Nonspecific lipid-transfer proteins in plant foods and pollens: an important allergen class

Purpose of reviewHere we focus our attention on the structural stability and physicochemical properties of plant nonspecific lipid-transfer proteins (nsLTPs) as keys to their allergenicity. We further present the current opinions on the route of sensitization and include the latest additions to the nsLTP allergen family. Recent findingsPlant nsLTPs are small cysteine-rich lipid-binding proteins that play a key role in plant resistance to biotic and abiotic stress. Besides their relevance for plant–pathogen interactions, nsLTPs have attracted interest as true food allergens which are of high importance to atopics in Mediterranean countries. It is now becoming clear that their molecular properties such as the remarkable stability to proteolysis and thermal denaturation are intrinsically linked to their allergenicity. These properties also facilitate sensitization via the gastrointestinal tract which allows these molecules to act as allergens independently of prior exposure to pollen. In addition, a group of allergenic pollen nsLTPs exists which seem to be only partially linked to the food nsLTPs by cross-reactivity. SummaryResearch into the family of nsLTPs will continue to provide insights about the particular molecular properties that make an nsLTP an allergen and how primary sensitization occurs.

Kiwifruit allergy across Europe: Clinical manifestation and IgE recognition patterns to kiwifruit allergens

BACKGROUND Kiwifruit is a common cause of food allergy. Symptoms range from mild to anaphylactic reactions. OBJECTIVE We sought to elucidate geographic differences across Europe regarding clinical patterns and sensitization to kiwifruit allergens. Factors associated with the severity of kiwifruit allergy were identified, and the diagnostic performance of specific kiwifruit allergens was investigated. METHODS This study was part of EuroPrevall, a multicenter European study investigating several aspects of food allergy. Three hundred eleven patients with kiwifruit allergy from 12 countries representing 4 climatic regions were included. Specific IgE to 6 allergens (Act d 1, Act d 2, Act d 5, Act d 8, Act d 9, and Act d 10) and kiwifruit extract were tested by using ImmunoCAP. RESULTS Patients from Iceland were mainly sensitized to Act d 1 (32%), those from western/central and eastern Europe were mainly sensitized to Act d 8 (pathogenesis-related class 10 protein, 58% and 44%, respectively), and those from southern Europe were mainly sensitized to Act d 9 (profilin, 31%) and Act d 10 (nonspecific lipid transfer protein, 22%). Sensitization to Act d 1 and living in Iceland were independently and significantly associated with severe kiwifruit allergy (odds ratio, 3.98 [P = .003] and 5.60 [P < .001], respectively). Using a panel of 6 kiwifruit allergens in ImmunoCAP increased the diagnostic sensitivity to 65% compared with 20% for skin prick tests and 46% ImmunoCAP using kiwi extract. CONCLUSION Kiwifruit allergen sensitization patterns differ across Europe. The use of specific kiwifruit allergens improved the diagnostic performance compared with kiwifruit extract. Sensitization to Act d 1 and living in Iceland are strong risk factors for severe kiwifruit allergy.

Fast: Towards safe and effective subcutaneous immunotherapy of persistent life-threatening food allergies

The FAST project (Food Allergy Specific Immunotherapy) aims at the development of safe and effective treatment of food allergies, targeting prevalent, persistent and severe allergy to fish and peach. Classical allergen-specific immunotherapy (SIT), using subcutaneous injections with aqueous food extracts may be effective but has proven to be accompanied by too many anaphylactic side-effects. FAST aims to develop a safe alternative by replacing food extracts with hypoallergenic recombinant major allergens as the active ingredients of SIT. Both severe fish and peach allergy are caused by a single major allergen, parvalbumin (Cyp c 1) and lipid transfer protein (Pru p 3), respectively. Two approaches are being evaluated for achieving hypoallergenicity, i.e. site-directed mutagenesis and chemical modification. The most promising hypoallergens will be produced under GMP conditions. After pre-clinical testing (toxicology testing and efficacy in mouse models), SCIT with alum-absorbed hypoallergens will be evaluated in phase I/IIa and IIb randomized double-blind placebo-controlled (DBPC) clinical trials, with the DBPC food challenge as primary read-out. To understand the underlying immune mechanisms in depth serological and cellular immune analyses will be performed, allowing identification of novel biomarkers for monitoring treatment efficacy. FAST aims at improving the quality of life of food allergic patients by providing a safe and effective treatment that will significantly lower their threshold for fish or peach intake, thereby decreasing their anxiety and dependence on rescue medication.