Role of the polypeptide backbone and post-translational modifications in cross-reactivity of Art v 1, the major mugwort pollen allergen

The Role of Defensins as Pollen and Food Allergens

PURPOSE OF REVIEW

Defensin-polyproline-linked proteins are relevant allergens in Asteraceae pollen. Depending on their prevalence and amount in the pollen source, they are potent allergens, as shown for the major mugwort pollen allergen Art v 1. Only a few allergenic defensins have been identified in plant foods, such as peanut and celery. This review provides an overview of structural and immunological features, IgE cross-reactivity, and diagnostic and therapeutic options regarding allergenic defensins.

RECENT FINDINGS

We present and critically review the allergenic relevance of pollen and food defensins. The recently identified Api g 7 from celeriac and other allergens potentially involved in Artemisia pollen-related food allergies are discussed and related to clinical severity and allergen stability. To specify Artemisia pollen-related food allergies, we propose the term "defensin-related food allergies" to account for defensin-polyproline-linked protein-associated food syndromes. There is increasing evidence that defensins are the causative molecules in several mugwort pollen-associated food allergies. A small number of studies have shown IgE cross-reactivity of Art v 1 with celeriac, horse chestnut, mango, and sunflower seed defensins, while the underlying allergenic molecule remains unknown in other mugwort pollen-associated food allergies. As these food allergies can cause severe allergic reactions, identification of allergenic food defensins and further clinical studies with larger patient cohorts are required. This will allow molecule-based allergy diagnosis and a better understanding of defensin-related food allergies to raise awareness of potentially severe food allergies due to primary sensitization to Artemisia pollen.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Similar Allergenicity to Different Artemisia Species Is a Consequence of Highly Cross-Reactive Art v 1-Like Molecules

Background and objectives: Pollens of weeds are relevant elicitors of type I allergies. While many Artemisia species occur worldwide, allergy research so far has only focused on Artemisia vulgaris. We aimed to characterize other prevalent Artemisia species regarding their allergen profiles. Materials and Methods: Aqueous extracts of pollen from seven Artemisia species were characterized by gel electrophoresis and ELISA using sera from mugwort pollen-allergic patients (n = 11). The cDNA sequences of defensin–proline-linked proteins (DPLPs) were obtained, and purified proteins were tested in a competition ELISA, in rat basophil mediator release assays, and for activation of Jurkat T cells transduced with an Art v 1-specific TCR. IgE cross-reactivity to other allergens was evaluated using ImmunoCAP and ISAC. Results: The protein patterns of Artemisia spp. pollen extracts were similar in gel electrophoresis, with a major band at 24 kDa corresponding to DPLPs, like the previously identified Art v 1. Natural Art v 1 potently inhibited IgE binding to immobilized pollen extracts. Six novel Art v 1 homologs with high sequence identity and equivalent IgE reactivity were identified and termed Art ab 1, Art an 1, Art c 1, Art f 1, Art l 1, and Art t 1. All proteins triggered mediator release and cross-reacted at the T cell level. The Artemisia extracts contained additional IgE cross-reactive molecules from the nonspecific lipid transfer protein, pectate lyase, profilin, and polcalcin family. Conclusions: Our findings demonstrate that DPLPs in various Artemisia species have high allergenic potential. Therefore, related Artemisia species need to be considered to be allergen elicitors, especially due to the consideration of potential geographic expansion due to climatic changes.

Prevention of allergy by virus-like nanoparticles (VNP) delivering shielded versions of major allergens in a humanized murine allergy model

Background

In high‐risk populations, allergen‐specific prophylaxis could protect from sensitization and subsequent development of allergic disease. However, such treatment might itself induce sensitization and allergies, thus requiring hypoallergenic vaccine formulations. We here characterized the preventive potential of virus‐like nanoparticles (VNP) expressing surface‐exposed or shielded allergens.

Methods

Full‐length major mugwort pollen allergen Art v 1 was selectively targeted either to the surface or to the inner side of the lipid bilayer envelope of VNP. Upon biochemical and immunological analysis, their preventive potential was determined in a humanized mouse model of mugwort pollen allergy.

Results

Virus‐like nanoparticles expressing shielded version of Art v 1, in contrast to those expressing surface‐exposed Art v 1, were hypoallergenic as they hardly induced degranulation of rat basophil leukemia cells sensitized with Art v 1‐specific mouse or human IgE. Both VNP versions induced proliferation and cytokine production of allergen‐specific T cells in vitro. Upon intranasal application in mice, VNP expressing surface‐exposed but not shielded allergen induced allergen‐specific antibodies, including IgE. Notably, preventive treatment with VNP expressing shielded allergen‐protected mice from subsequent sensitization with mugwort pollen extract. Protection was associated with a Th1/Treg‐dominated cytokine response, increased Foxp3⁺ Treg numbers in lungs, and reduced lung resistance when compared to mice treated with empty particles.

Conclusion

Virus‐like nanoparticles represent a novel and versatile platform for the in vivo delivery of allergens to selectively target T cells and prevent allergies without inducing allergic reactions or allergic sensitization.

Mugwort Pollen-Related Food Allergy: Lipid Transfer Protein Sensitization and Correlation With the Severity of Allergic Reactions in a Chinese Population

PURPOSE

Little is known about the importance of lipid transfer protein (LTP) sensitization in China. In this study, we investigated the relationship between LTP sensitization and the severity of clinical symptoms in a population of patients with mugwort pollen-related food allergy.

METHODS

Food-induced symptoms were evaluated in 148 patients with mugwort pollen allergy by a standardized questionnaire. Specific immunoglobulin E (IgE) to Art v 1, Art v 3, Pru p 3, Ara h 9 and Cor a 8 were quantified by ImmunoCAP. Immunoblotting of peach extracts were performed with sera from peach-allergic patients.

RESULTS

In total, 72% (107/148) of the study population experienced food allergy. Forty-eight percent (51/107) of patients with mugwort pollen-related food allergy experienced at least 1 episode of food-induced anaphylaxis. Food allergy correlated with IgE reactivity to Art v 3, but not to Art v 1. Sensitization to Pru p 3, Ara h 9 or Cor a 8 was prevalent (80%, 69 or 63%, respectively) among individuals with food allergy. Food allergic patients with systemic reactions (SR) had higher values for Pru p 3, Ara h 9 and Cor a 8 than patients with oral allergy syndrome (OAS). Furthermore, the strong IgE reactivity detected in immunoblots of peach extracts indicated that Pru p 3 was the major allergen and was more prevalent in patients with SR than in patients with OAS (100% vs. 55%).

CONCLUSIONS

LTPs are major food allergens for mugwort pollen-related food allergy in China, and may contribute to SR.

Anaphylactic reaction in patient allergic to mango

Background

An allergy to mango is extremely rare. The antigenic composition of the fruit is not fully known. Profilin from mango has a structure similar to birch tree profiling: it is responsible for cross-reactions between mango and pear, apple, and peach. A panallergen with a structure similar to mugwort defensin (Art v 1) which cross-reacts with celery, carrot, peanuts, pepper, aniseed, and caraway has been previously described.

Case study

A female patient, 30 years old, was admitted in February 2017 because of recurrent allergic reactions following consumption of various foods. The most severe allergic reaction in the patient’s life occurred after eating a mango fruit. Within several minutes the patient developed a generalised urticaria, followed by facial oedema, strong stomach pain and watery diarrhoea. The diagnostics involved skin tests with a set of inhalatory and food allergens, including native skin tests. The patient also experienced symptoms of recurrent, generalized urticaria in connection with consumption of various types of food, especially complex dishes containing many different ingredients. Additionally, an interview revealed that the patient was experiencing symptoms of the oral allergy syndrome after ingesting various fruit and vegetables, especially during late summer and fall. Diagnostics was extended by determining the levels of IgE specific for allergen components, using the ImmunoCap ISAC method. In order to confirm the occurence of a cross-reaction between mugwort and mango allergens, we performed the inhibition test of IgE specific for mugwort using a mango allergen extract and ImmunoCap matrix.

Results

Skin prick tests (SPT) were positive for allergens of grass 7 mm; weeds 8 mm; cat’s fur 5 mm; mugwort 6 mm. SPT were also positive for mango. The level of specific IgE was increased for allergens of mugwort, grass, celery, pepper, carrot, mango, banana, peach, and apple. The ImmunoCap ISAC test demonstrated a high level of specific IgE rPhl p 1 (timothy grass) and Art v 1 (mugwort). We also performed the IgE inhibition test using both mango extract and ImmunoCap matrix and confirmed a cross-reaction with Art v 1 in the pathogenesis of symptoms observed in the patient.

Conclusions

An anaphylactic reaction to consumed mango, resulting from cross-allergy with mugwort Art v 1 was diagnosed in the patient. Acute urticarial in this case is a manifestation of IgE-mediated food allergy. During in vitro diagnostic procedures we found an elevated concentration of IgE specific to several food allergens (including celery, peppers, carrot, banana, peach, apple, shrimp). The elimination diet removing allergens the patient was allergic to was recommended. Considering the anaphylactic reaction the patient was instructed to carry a rescue set composed of an adrenaline autosyringe, steroids, and antihistamines.

The Gut Microbiome Feelings of the Brain: A Perspective for Non-Microbiologists

Objectives: To comprehensively review the scientific knowledge on the gut-brain axis. Methods: Various publications on the gut-brain axis, until 31 July 2017, were screened using the Medline, Google, and Cochrane Library databases. The search was performed using the following keywords: "gut-brain axis", "gut-microbiota-brain axis", "nutrition microbiome/microbiota", "enteric nervous system", "enteric glial cells/network", "gut-brain pathways", "microbiome immune system", "microbiome neuroendocrine system" and "intestinal/gut/enteric neuropeptides". Relevant articles were selected and reviewed. Results: Tremendous progress has been made in exploring the interactions between nutrients, the microbiome, and the intestinal, epithelium-enteric nervous, endocrine and immune systems and the brain. The basis of the gut-brain axis comprises of an array of multichannel sensing and trafficking pathways that are suggested to convey the enteric signals to the brain. These are mediated by neuroanatomy (represented by the vagal and spinal afferent neurons), the neuroendocrine-hypothalamic-pituitary-adrenal (HPA) axis (represented by the gut hormones), immune routes (represented by multiple cytokines), microbially-derived neurotransmitters, and finally the gate keepers of the intestinal and brain barriers. Their mutual and harmonious but intricate interaction is essential for human life and brain performance. However, a failure in the interaction leads to a number of inflammatory-, autoimmune-, neurodegenerative-, metabolic-, mood-, behavioral-, cognitive-, autism-spectrum-, stress- and pain-related disorders. The limited availability of information on the mechanisms, pathways and cause-and-effect relationships hinders us from translating and implementing the knowledge from the bench to the clinic. Implications: Further understanding of this intricate field might potentially shed light on novel preventive and therapeutic strategies to combat these disorders. Nutritional approaches, microbiome manipulations, enteric and brain barrier reinforcement and sensing and trafficking modulation might improve physical and mental health outcomes.

Sunflower seed allergy

Sunflower seeds are a rare source of allergy, but several cases of occupational allergies to sunflowers have been described. Sunflower allergens on the whole, however, still await precise and systematic description. We present an interesting case of a 40-year-old male patient, admitted to hospital due to shortness of breath and urticaria, both of which appeared shortly after the patient ingested sunflower seeds. Our laryngological examination revealed swelling of the pharynx with retention of saliva and swelling of the mouth and tongue. During diagnostics, 2 months later, we found that skin prick tests were positive to mugwort pollen (12/9 mm), oranges (6/6 mm), egg protein (3/3 mm), and hazelnuts (3/3 mm). A native prick by prick test with sunflower seeds was strongly positive (8/5 mm). Elevated concentrations of specific IgE against weed mix (inc. lenscale, mugwort, ragweed) allergens (1.04 IU/mL), Artemisia vulgaris (1.36 IU/mL), and Artemisia absinthium (0.49 IU/mL) were found. An ImmunoCap ISAC test found an average level of specific IgE against mugwort pollen allergen component Art v 1 - 5,7 ISU-E, indicating an allergy to mugwort pollen and low to medium levels of specific IgE against lipid transfer proteins (LTP) found in walnuts, peanuts, mugwort pollen, and hazelnuts. Through the ISAC inhibition test we proved that sunflower seed allergen extracts contain proteins cross-reactive with patients' IgE specific to Art v 1, Art v 3, and Jug r 3. Based on our results and the clinical pattern of the disease we confirmed that the patient is allergic to mugwort pollen and that he had an anaphylactic reaction as a result of ingesting sunflower seeds. We suspected that hypersensitivity to sunflower LTP and defensin-like proteins, both cross-reactive with mugwort pollen allergens, were the main cause of the patient's anaphylactic reaction.

EAACI Molecular Allergology User's Guide

The availability of allergen molecules ('components') from several protein families has advanced our understanding of immunoglobulin E (IgE)-mediated responses and enabled 'component-resolved diagnosis' (CRD). The European Academy of Allergy and Clinical Immunology (EAACI) Molecular Allergology User's Guide (MAUG) provides comprehensive information on important allergens and describes the diagnostic options using CRD. Part A of the EAACI MAUG introduces allergen molecules, families, composition of extracts, databases, and diagnostic IgE, skin, and basophil tests. Singleplex and multiplex IgE assays with components improve both sensitivity for low-abundance allergens and analytical specificity; IgE to individual allergens can yield information on clinical risks and distinguish cross-reactivity from true primary sensitization. Part B discusses the clinical and molecular aspects of IgE-mediated allergies to foods (including nuts, seeds, legumes, fruits, vegetables, cereal grains, milk, egg, meat, fish, and shellfish), inhalants (pollen, mold spores, mites, and animal dander), and Hymenoptera venom. Diagnostic algorithms and short case histories provide useful information for the clinical workup of allergic individuals targeted for CRD. Part C covers protein families containing ubiquitous, highly cross-reactive panallergens from plant (lipid transfer proteins, polcalcins, PR-10, profilins) and animal sources (lipocalins, parvalbumins, serum albumins, tropomyosins) and explains their diagnostic and clinical utility. Part D lists 100 important allergen molecules. In conclusion, IgE-mediated reactions and allergic diseases, including allergic rhinoconjunctivitis, asthma, food reactions, and insect sting reactions, are discussed from a novel molecular perspective. The EAACI MAUG documents the rapid progression of molecular allergology from basic research to its integration into clinical practice, a quantum leap in the management of allergic patients.

A Cross-Reactive Human Single-Chain Antibody for Detection of Major Fish Allergens, Parvalbumins, and Identification of a Major IgE-Binding Epitope

Fish allergy is associated with moderate to severe IgE-mediated reactions to the calcium binding parvalbumins present in fish muscle. Allergy to multiple fish species is caused by parvalbumin-specific cross-reactive IgE recognizing conserved epitopes. In this study, we aimed to produce cross-reactive single chain variable fragment (scFv) antibodies for the detection of parvalbumins in fish extracts and the identification of IgE epitopes. Parvalbumin-specific phage clones were isolated from the human ETH-2 phage display library by three rounds of biopanning either against cod parvalbumin or by sequential biopanning against cod (Gad m 1), carp (Cyp c 1) and rainbow trout (Onc m 1) parvalbumins. While biopanning against Gad m 1 resulted in the selection of clones specific exclusively for Gad m 1, the second approach resulted in the selection of clones cross-reacting with all three parvalbumins. Two clones, scFv-gco9 recognizing all three parvalbumins, and scFv-goo8 recognizing only Gad m 1 were expressed in the E. coli non-suppressor strain HB2151 and purified from the periplasm. scFv-gco9 showed highly selective binding to parvalbumins in processed fish products such as breaded cod sticks, fried carp and smoked trout in Western blots. In addition, the scFv-gco9-AP produced as alkaline phosphatase fusion protein, allowed a single-step detection of the parvalbumins. In competitive ELISA, scFv-gco9 was able to inhibit binding of IgE from fish allergic patients’ sera to all three β-parvalbumins by up to 80%, whereas inhibition by scFv-goo8 was up to 20%. ¹H/¹⁵N HSQC NMR analysis of the rGad m 1:scFv-gco9 complex showed participation of amino acid residues conserved among these three parvalbumins explaining their cross-reactivity on a molecular level. In this study, we have demonstrated an approach for the selection of cross-reactive parvalbumin-specific antibodies that can be used for allergen detection and for mapping of conserved epitopes.

Position paper of the EAACI: food allergy due to immunological cross-reactions with common inhalant allergens

In older children, adolescents, and adults, a substantial part of all IgE-mediated food allergies is caused by cross-reacting allergenic structures shared by inhalants and foods. IgE stimulated by a cross-reactive inhalant allergen can result in diverse patterns of allergic reactions to various foods. Local, mild, or severe systemic reactions may occur already after the first consumption of a food containing a cross-reactive allergen. In clinical practice, clinically relevant sensitizations are elucidated by skin prick testing or by the determination of specific IgE in vitro. Component-resolved diagnosis may help to reach a diagnosis and may predict the risk of a systemic reaction. Allergy needs to be confirmed in cases of unclear history by oral challenge tests. The therapeutic potential of allergen immunotherapy with inhalant allergens in pollen-related food allergy is not clear, and more placebo-controlled studies are needed. As we are facing an increasing incidence of pollen allergies, a shift in sensitization patterns and changes in nutritional habits, and the occurrence of new, so far unknown allergies due to cross-reactions are expected.

Cross-reactivity between aeroallergens and food allergens

In patients with respiratory allergy, cross-reactivity between aeroallergens and foods may induce food allergy, symptoms ranging from oral allergy syndrome to severe anaphylaxis. Clinical entities due to IgE sensitization to cross-reactive aeroallergen and food allergen components are described for many sources of plant origin (pollen-food syndromes and associations, such as birch-apple, cypress-peach and celery-mugwort-spice syndromes, and mugwort-peach, mugwort-chamomile, mugwort-mustard, ragweed-melon-banana, goosefoot-melon associations), fungal origin (Alternaria-spinach syndrome), and invertebrate, mammalian or avian origin (mite-shrimp, cat-pork, and bird-egg syndromes). Clinical cases of allergic reactions to ingestion of food products containing pollen grains of specific plants, in patients with respiratory allergy to Asteraceae pollen, especially mugwort and ragweed, are also mentioned, for honey, royal jelly and bee polen dietary supplements, along with allergic reactions to foods contaminated with mites or fungi in patients with respiratory allergy to these aeroallergens. Medical history and diagnosis approach may be guided by the knowledge about the diverse cross-reacting allergens involved, and by the understanding of these clinical entities which may vary significantly or may be overlapping. The association between primary IgE sensitization with respiratory symptoms to inhaled allergens and food allergy due to cross-reactive allergen components is important to assess in allergy practice. The use of molecular-based diagnosis improves the understanding of clinically relevant IgE sensitization to cross-reactive allergen components from aeroallergen sources and foods.

Marker allergens of weed pollen - basic considerations and diagnostic benefits in the clinical routine: Part 16 of the Series Molecular Allergology

The term weed is referring to plants used as culinary herbs and medicinal plants as well as ecologically adaptive and invasive segetal plants. In Europe, pollen of ragweed, mugwort, English plantain and pellitory are the main elicitors of weed pollen allergies. Presently, 35 weed pollen allergens have been identified. The most relevant belong to the protein families of pectate lyases, defensin-like proteins, non-specific lipid transfer proteins, and Ole e 1-like proteins. The sensitization frequency depends on geographic regions and might affect more than 50 % of pollen allergic patients in distinct regions. Due to overlapping flowering seasons, similar habitats, polysensitizations and cross-reactive (pan)-allergens, it is difficult to diagnose genuine weed pollen sensitization using pollen extracts. Marker allergens for component-resolved diagnostics are available for the important weed pollen. These are Amb a 1 (ragweed), Art v 1 (mugwort), Pla l 1 (English plantain) and Par j 2 (pellitory). Molecule-based approaches can be used to identify the primary sensitizer and thus enable selection of the appropriate weed pollen extracts for allergen immunotherapy.

Food allergies resulting from immunological cross-reactivity with inhalant allergens: Guidelines from the German Society for Allergology and Clinical Immunology (DGAKI), the German Dermatology Society (DDG), the Association of German Allergologists (AeDA) and the Society for Pediatric Allergology and Environmental Medicine (GPA)

A large proportion of immunoglobulin E (IgE)-mediated food allergies in older children, adolescents and adults are caused by cross-reactive allergenic structures. Primary sensitization is most commonly to inhalant allergens (e.g. Bet v 1, the major birch pollen allergen). IgE can be activated by various cross-reactive allergens and lead to a variety of clinical manifestations. In general, local and mild — in rare cases also severe and systemic — reactions occur directly after consumption of the food containing the cross-reactive allergen (e. g. plant-derived foods containing proteins of the Bet v 1 family). In clinical practice, sensitization to the primary responsible inhalant and/or food allergen can be detected by skin prick tests and/or in vitro detection of specific IgE. Component-based diagnostic methods can support clinical diagnosis. For individual allergens, these methods may be helpful to estimate the risk of systemic reactions. Confirmation of sensitization by oral provocation testing is important particulary in the case of unclear case history. New, as yet unrecognized allergens can also cause cross-reactions.

The therapeutic potential of specific immunotherapy (SIT) with inhalant allergens and their effect on pollen-associated food allergies is currently unclear: results vary and placebo-controlled trials will be necessary in the future. Pollen allergies are very common. Altogether allergic sensitization to pollen and cross-reactive food allergens are very common in our latitudes. The actual relevance has to be assessed on an individual basis using the clinical information.

Cite this as Worm M, Jappe U, Kleine-Tebbe J, Schäfer C, Reese I, Saloga J, Treudler R, Zuberbier T, Wassmann A, Fuchs T, Dölle S, Raithel M, Ballmer-Weber B, Niggemann B, Werfel T. Food allergies resulting from immunological cross-reactivity with inhalant allergens. Allergo J Int 2014; 23: 1–16 DOI 10.1007/s40629-014-0004-6

Allergens of weed pollen: an overview on recombinant and natural molecules

Weeds represent a botanically unrelated group of plants that usually lack commercial or aesthetical value. Pollen of allergenic weeds are able to trigger type I reactions in allergic patients and can be found in the plant families of Asteraceae, Amaranthaceae, Plantaginaceae, Urticaceae, and Euphorbiaceae. To date, 34 weed pollen allergens are listed in the IUIS allergen nomenclature database, which were physicochemically and immunologically characterized to varying degrees. Relevant allergens of weeds belong to the pectate lyase family, defensin-like family, Ole e 1-like family, non-specific lipid transfer protein 1 family and the pan-allergens profilin and polcalcins. This review provides an overview on weed pollen allergens primarily focusing on the molecular level. In particular, the characteristics and properties of purified recombinant allergens and hypoallergenic derivatives are described and their potential use in diagnosis and therapy of weed pollen allergy is discussed.

Expression of the major mugwort pollen allergen Art v 1 in tobacco plants and cell cultures: problems and perspectives for allergen production in plants

An economic and cheap production of large amounts of recombinant allergenic proteins might become a prerequisite for the common use of microarray-based diagnostic allergy assays which allow a component-specific diagnosis. A molecular pharming strategy was applied to express the major allergen of Artemisia vulgaris pollen, Art v 1, in tobacco plants and tobacco cell cultures. The original Art v 1 with its endogenous signal peptide which directs Art v 1 to the secretory pathway, was expressed in transiently transformed tobacco leaves but was lost in stable transformed tobacco plants during the alternation of generations. Using a light-regulated promoter and "hiding" the recombinant Art v 1 in the ER succeeded in expression of Art v 1 over three generations of tobacco plants and in cell cultures generated from stable transformed plants. However, the amounts of the recombinant allergen were sufficient for analysis but not high enough to allow an economic production. Although molecular pharming has been shown to work well for the production of non-plant therapeutic proteins, it might be less efficient for closely related plant proteins.

Proteomic analysis in the identification of allergenic molecules

Conventional and innovative strategies can be exploited to identify and characterize new allergenic proteins. With the aim of obtaining suggestions for future improvements, this article describes our attempt to understand and describe some of the advantages and pitfalls of the methodologies and procedures often used in this field. The analysis includes the protein extract preparation, starting from the allergenic source, the separation of the proteins contained in a mixture and the detection, identification and characterization of IgE-binding molecules. Classic and emerging proteomic technologies, including mass spectrometry-based methodologies, Edman degradation procedure, microarray-based techniques and bioinformatics search strategies, have been explored. A comparative analysis of biochemistry-based proteomics and molecular biology strategies has also been given.

Bee pollen: a dangerous food for allergic children. Identification of responsible allergens

BACKGROUND

Bee pollen has been proposed as a food supplement, but it can be a dangerous food for people with allergy. We study an allergic reaction after ingestion of bee pollen in a 4-year-old boy who had developed rhinitis in the last spring and autumn.

METHODS

We performed a prick-by-prick test with bee pollen and skin prick tests with the most important local pollens, house dust mites, common fungi, and animal danders. The levels of serum tryptase, serum total IgE and specific IgE against bee venom and local pollen extracts were determined. The composition of the bee pollen was analysed and SDS-PAGE immunoblotting and blotting-inhibition were carried out.

RESULTS

Prick tests were positive to bee pollen and all local pollens extracts and negative to any other allergen sources. The bee pollen sample contained pollens from Quercus genus, and Asteraceae (Compositae) and Rosaceae families. Total IgE was 435 kU/l. Serum specific IgE to bee pollen was 6 kU/l and greater than 0.35 kU/L against pollens from Artemisia vulgaris, Taraxacum officinalis, Cupressus arizonica, Olea europaea, Platanus acerifolia and Lolium perenne as well as to n Art v 1 and other pollen marker allergens. Tryptase level was 3.5 mcg/mL. SDS-PAGE immunoblotting-inhibition points to Asteraceae pollen as the possible cause of the allergic reaction.

CONCLUSION

Foods derived from bees can be dangerous to people with allergy to pollen.