Identification and quantification of tomato allergens: in vitro characterization of six different varieties

Effects of variety, maturity and storage conditions on the allergic potential of kiwifruit and its relationship with antioxidant activity

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Allergenicity of kiwifruit strongly associated with its physiological attributes.

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10-day storage of kiwifruit at 20 °C increased the Act d 2 content by 50 %.

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Act d 2 content in the seeds was 4-fold higher than that of peel.

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Act d 2 content showed a negative relationship with antioxidant activity.

This work aimed to study the influences of physiological characteristics (variety, maturity, and fruit components) and storage conditions on the allergenic potential of kiwifruit. The results found kiwifruit allergen (Act d 2) is only measured in the green kiwifruit rather than golden kiwifruit. The Act d 2 content of seed is 2-fold and 4-fold higher than that of pulp and peel, respectively. The highest Act d 2 allergen content was determined in ripe kiwifruit, followed by overripe fruit and unripe fruit. A 50 % of enhancement in Act d 2 content was observed after 10-day storage at 20 °C. Further, the Act d 2 content showed a negative relationship with the ascorbic acid content and total antioxidant activity at various conditions. Thus, antioxidants as important factors may involve the regulation of Act d 2 in kiwifruit. These findings could provide a deep understanding in the distribution of Act d 2.

Tomato Allergy: The Characterization of the Selected Allergens and Antioxidants of Tomato (Solanum lycopersicum)-A Review

Tomatoes are one of the most broadly produced and consumed crop plants. They are the source of health-promoting nutrients such as antioxidants, including ascorbic acid, polyphenols, or carotenoids. Despite the beneficial role of tomatoes in the daily diet, they have been confirmed as one of the most prevalent allergenic vegetables. Food allergies can cause many clinical symptoms, e.g., in the gastrointestinal tract, skin, and lungs, as well as anaphylactic shock. A huge amount of clinical research has been carried out to improve the understanding of the immunological mechanisms that lead to the lack of tolerance of food antigens, which can result in either immunoglobulin E (IgE)-mediated reactions or non-IgE-mediated reactions. Lifestyle and diet play an important role in triggering food allergies. Allergy to tomatoes is also linked to other allergies, such as grass pollen and latex allergy. Numerous attempts have been made to identify and characterize tomato allergens; however, the data available on the subject are not sufficient.

Update on dietary therapy for eosinophilic esophagitis in children and adults

Eosinophilic esophagitis (EoE) is a chronic inflammatory esophageal disease triggered predominantly, but not excusively, by food antigens. Elimination diet thus remains the only therapy targeting the cause of the disease. Importantly, EoE is a unique form of non-IgE mediated food allergy, largely dependant upon delayed, cell-mediated hypersensitivity. Areas covered: A comprehensive review of literature to summarize and update the most relevant advances on dietary therapy for pediatric and adult EoE patients is conducted. Expert commentary: None of the currently available food allergy tests adequately predict food triggers for EoE, especially in adults. Elemental diet (exclusive feeding with aminoacid-based formulas) and empiric six-food elimination diet, withdrawing cow´s milk, wheat, egg, soy, nuts and fish/seafood for 6 weeks, have consistently shown the best cure rates. However, their high level of restriction and need for multiple endoscopies (top-down approach) have been a deterrent for patients and physicians. Less restrictive empiric schemes, like a four-food (animal milk, gluten-containing cereals, egg, legumes) or a two-food (animal milk and gluten-containing cereals) elimination diet have lately shown encouraging results. Therefore, a novel step-up strategy (2-4-6) may enhance patient uptake and promptly identify most responders to empiric diets with few food triggers, besides saving unnecessary dietary restrictions and endoscopic procedures.

Standardization and Regulation of Allergen Products in the European Union

Product-specific standardization is of prime importance to ensure persistent quality, safety, and efficacy of allergen products. The regulatory framework in the EU has induced great advancements in the field in the last years although national implementation still remains heterogeneous. Scores of methods for quantification of individual allergen molecules are developed each year and also the challenging characterization of chemically modified allergen products is progressing. However, despite the unquestionable increase in knowledge and the subsequent improvements in control of quality parameters of allergen products, an important aim has not been reached yet, namely cross-product comparability. Still, comparison of allergen product potency, either based on total allergenic activity or individual allergen molecule content, is not possible due to a lack of standard reference preparations in conjunction with validated standard methods. This review aims at presenting the most recent developments in product-specific standardization as well as activities to facilitate cross-product comparability in the EU.

Impact of Wild Loci on the Allergenic Potential of Cultivated Tomato Fruits

Tomato (Solanum lycopersicum) is one of the most extensively consumed vegetables but, unfortunately, it is also able to induce allergic reactions. In the past, it has been shown that the choice of tomato cultivar significantly influenced the allergic reaction of tomato allergic subjects. In this study we investigated the allergenic potential of the cultivated tomato line M82 and of two selected lines carrying small chromosome regions from the wild species Solanum pennellii (i.e. IL7-3 and IL12-4). We evaluated the positive interactions of IgEs of allergic subjects in order to investigate the different allergenic potential of the lines under investigation. We used proteomic analyses in order to identify putative tomato allergens. In addition, bioinformatic and transcriptomic approaches were applied in order to analyse the structure and the expression profiles of the identified allergen-encoding genes. These analyses demonstrated that fruits harvested from the two selected introgression lines harbour a different allergenic potential as those from the cultivated genotype M82. The different allergenicity found within the three lines was mostly due to differences in the IgE recognition of a polygalacturonase enzyme (46 kDa), one of the major tomato allergens, and of a pectin methylesterase (34 kDa); both the proteins were more immunoreactive in IL7-3 compared to IL12-4 and M82. The observed differences in the allergenic potential were mostly due to line-dependent translational control or post-translational modifications of the allergens. We demonstrated, for the first time, that the introgression from a wild species (S. pennellii) in the genomic background of a cultivated tomato line influences the allergenic properties of the fruits. Our findings could support the isolation of favorable wild loci promoting low allergenic potential in tomato.

Allergenic Potential of Tomatoes Cultivated in Organic and Conventional Systems

Tomatoes (Lycopersicon esculentum Mill.) are a widely consumed vegetables and contain many health beneficial micronutrients. Unfortunately, they may also cause adverse allergic reactions in sensitized people. Many studies, conducted in recent years, indicate that organically produced vegetables have higher nutritional value, improved sensory quality and contain more health-enhancing bioactive compounds than vegetables grown under the conventional system. However, the relation between organic methods of cultivation and allergenic potential of tomatoes has received little scientific attention. This study analyzed samples of five tomato cultivars taken from organic and conventional systems over three consecutive years. The content of profilin, Bet v 1 and lipid transfer protein (LTP) analogues in tomato samples was determined using an indirect ELISA assay. Substantial quantities of these proteins were found in certain cultivars across all three years of cultivation. On the basis of these findings, organically grown tomatoes appear to offer little advantage over conventionally cultivated plants in terms of reduced allergenic potential.

Control Process for Manufacturing and Standardization of Allergenic Molecules

It is widely accepted that the success of the allergen immunotherapy (AIT), beyond clinical parameters such as dose, dosage regimen, or compliance, depends on the quality and composition of the final products used in the vaccines. Allergenic vaccines are pharmaceutical preparations derived from the natural sources which contain the allergenic components responsible for allergic sensitization. The selection of the appropriate allergenic sources must be a requirement. They suffer a dramatic transformation during the manufacturing process which renders a biologically standardized final product. The inclusion of the appropriate control analyses in the manufacturing process has demonstrated to be an efficient method to guarantee the quality and homogeneity of the final product as well as being a very useful tool for saving time and money. In this context, in the last years, the Regulatory Agencies have released specific guidelines to guarantee the manufacturing of the most appropriate products for the treatment of patients.

Profilin sensitisation in a Mediterranean population

BACKGROUND

Sensitisation to pan-allergens has become an interesting tool for the study of the allergenic profile of different populations. Profilins are one of the most common pan-allergens to be studied because they are responsible for a large number of sensitisations and are clearly related to cross-reactivity and co-sensitisation.

OBJECTIVES

The objective of this study was to investigate the profile of sensitisation to profilins and to correlate it with sensitisation to foods and pollens.

METHODS

Six hundred and fifty-four consecutive patients were skin-prick tested with a battery of common allergens including pollens, epithelia, mites and moulds and profilin and divided into three groups depending on their sensitisation profile (non-atopic, atopic with pollinosis and atopic without pollinosis). Patients with symptoms were challenged and diagnosed with the offending food extracts. Profilin sensitisation was identified and analysed in detail.

RESULTS

According to the classification of the population, the prevalence of profilin sensitisation was estimated at 2.9% in patients suffering respiratory allergy, 4.2% in atopic patients, and 5.9% in pollen-sensitised individuals. Positive association was observed between pollen (except Cupressus and olive) and profilin but not with moulds, mites or epithelia. With respect to foods, positive association was only observed between profilin and melon sensitisation. Lastly, in terms of symptoms, positive association was only observed between profilin sensitisation and OAS.

CONCLUSION

Profilin sensitisation seems to be a marker of pollen-related poly-sensitisation in our area. Pan-allergen diagnosis seems to be an essential tool for developing and improving selection of the correct treatment for allergic patients.

Maize IgE binding proteins: each plant a different profile?

Background

Allergies are nearly always triggered by protein molecules and the majority of individuals with documented immunologic reactions to foods exhibit IgE hypersensitivity reactions. In this study we aimed to understand if natural differences, at proteomic level, between maize populations, may induce different IgE binding proteins profiles among maize-allergic individuals. We also intended to deepen our knowledge on maize IgE binding proteins.

Results

In order to accomplish this goal we have used proteomic tools (SDS-PAGE and 2-D gel electrophoresis followed by western blot) and tested plasma IgE reactivity from four maize-allergic individuals against four different protein fractions (albumins, globulins, glutelins and prolamins) of three different maize cultivars. We have observed that maize cultivars have different proteomes that result in different IgE binding proteins profiles when tested against plasma from maize-allergic individuals. We could identify 19 different maize IgE binding proteins, 11 of which were unknown to date. Moreover, we found that most (89.5%) of the 19 identified potential maize allergens could be related to plant stress.

Conclusions

These results lead us to conclude that, within each species, plant allergenic potential varies with genotype. Moreover, considering the stress-related IgE binding proteins identified, we hypothesise that the environment, particularly stress conditions, may alter IgE binding protein profiles of plant components.