IgE-Reactivity Pattern of Tomato Seed and Peel Nonspecific Lipid-Transfer Proteins after in Vitro Gastrointestinal Digestion.

The influence of gastrointestinal digestion on the immunological properties of three different nonspecific lipid-transfer proteins (nsLTPs) described in tomato fruit has been assessed using an in vitro system mimicking the stomach and intestine digestion conditions. Tomato peel/pulp nsLTP, Sola l 3, was degraded after digestion, although the immunoglobulin E (IgE) recognition of intact protein and a 10 kDa band were still observed after 30 min of duodenal digestion in the presence of phosphatidylcholine. The tomato seed nsLTP, Sola l 7, showed a higher stability than the other seed allergen, Sola l 6, during digestion. Sola l 7 showed an IgE immunoreactive 6.5 kDa band in immunoblotting analysis, retaining up to 7% of its IgE-binding capacity in inhibition ELISA test after 60 min of duodenal digestion and keeping intact its ability to activate basophils after digestion. These results suggest that the tomato seed allergen Sola l 7 might be considered as an important allergen in the induction of allergic responses to tomato due to its high stability against gastrointestinal digestion.

[Allergy to vegetables belonging to the Solanaceae family]. / Alergia a vegetales pertenecientes a la familia de las solanáceas.

BACKGROUND: Although cross-reactivity with other plant-based foods and latex has been described, allergies to potatoes and tomatoes are uncommon. OBJECTIVE: To study the different sensitization patterns in patients who are allergic to potatoes and/or tomatoes. METHODS: Skin prick tests were carried out with fresh foods and extracts, specific IgE determination and allergen detection by SDS-PAGE and IgE-Immunoblotting with both raw and heated potato and tomato extracts. RESULTS: In 10 patients, two thermostable allergens to potato extract were detected; the first one with a molecular weight that is compatible with Sola t 1 (43 kDa, patatin) and the second one with a molecular weight of 14-22 kDa, which could correspond to the allergens Sola t 4 (16 kDa) and Sola t 2 and Sola t 3 (21 kDa); in two patients who are allergic to potatoes and two patients who are allergic to tomatoes, a thermostable allergen that is compatible to Sola I 2 (50 kDa) was detected. The patient had presented oral allergy syndrome with some types of potatoes and showed higher IgE reactivity to two thermostable potato allergens. CONCLUSIONS: The allergen sensitization patterns were similar in all the patients that had been studied, regardless of the symptoms. A new allergen involved in the allergy to solanaceae plants has been detected.

Antecedentes: Aunque se ha descrito reactividad cruzada con alimentos vegetales y látex, la alergia a la papa y al tomate es infrecuente. Objetivo: Estudiar los diferentes patrones de sensibilización en pacientes alérgicos a la patata o tomate. Métodos: Se realizaron pruebas de punción cutánea con extractos y alimentos frescos, determinación de IgE específica y detección de alérgenos mediante SDS-PAGE e IgE-Immunoblotting con extractos de patata y tomate crudos y calientes. Resultados: En 10 pacientes se detectaron alérgenos termoestables a extracto de patata, uno de peso molecular compatible con Sola t 1 (43 kDa, patatina) y otro de 14-22 kDa que podría corresponder a los alérgenos Sola t 4 (16 kDa), Sola t 2 y Sola t 3 (21 kDa); en dos pacientes alérgicos a la patata y dos alérgicos al tomate se detectó un alérgeno termoestable de aproximadamente 42 kDa. En un paciente alérgico al tomate se detectó un alérgeno termoestable compatible con Sola l 2 (50 kDa); había presentado síndrome de alergia oral con algunos tipos de patatas y mostró mayor reactividad IgE a dos alérgenos termoestables de la patata. Conclusiones: Los patrones de sensibilización a los alérgenos fueron similares en los pacientes, independientemente de los síntomas. Se ha detectado un nuevo alérgeno implicado en la alergia a las solanáceas.

Pollen food allergy syndrome to tomato in mountain cedar pollen hypersensitivity.

BACKGROUND: Mountain cedar pollen is recognized as a major cause of seasonal hypersensitivity in the US. We describe here that a subgroup of these patients also suffer from pollen food allergy syndrome (PFAS). OBJECTIVE: We performed this study to determine the frequency of PFAS among patients with mountain cedar hypersensitivity. METHODS: We performed mail-out/telephone surveys of 800 mountain cedar-sensitive patients in Austin, TX. The subjects for this survey were selected by telephone screening, and skin and serologic testing. We performed immunoblot inhibition assay and mass spectrometry (MS) to identify the allergens that cause PFAS. RESULTS: Of the 28 patients with suspected food allergies, 15 had clinical manifestations of PFAS. Eleven of them had positive skin tests to tomato, six to banana, and one to apple. The subjects with PFAS have stronger cutaneous and in vitro reactivity to cedar pollen. The intensities of the tomato and banana reactivity were correlated with the cedar reactivity. The results of the ImmunoCAP inhibition experiments demonstrated a strong cross-reactivity between IgE antibodies to cedar pollen and fruits. This suggested that their primary sensitization was to cedar pollen, since absorption with cedar pollen extract strongly inhibited reactivity to each of the fruits, while the absorption with tomato extract did not significantly inhibit IgE binding to cedar extract. We determined that polygalacturonase 2 A (PG2 A) in tomato is the cause of PFAS. CONCLUSION: This is the first report of a PFAS in patients with mountain cedar pollinosis. Sensitivity to tomato, banana, and apple should be considered in cedar-sensitive patients.

Two nonspecific lipid transfer proteins (nsLTPs) from tomato seeds are associated to severe symptoms of tomato-allergic patients.

SCOPE: Tomato has become one of the most consumed vegetables worldwide, but its intake is often accompanied by an increasing risk of inducing allergic symptoms. The aim of the work was the identification of new seed-specific allergens associated with severe symptoms in patients allergic to this edible vegetable. METHODS AND RESULTS: We used 22 sera from well-defined tomato-allergic patients. Tomato seed proteins were purified and analyzed for biochemical and immunological characterization. A mixture of two associated IgE-binding nsLTPs was purified from tomato seeds. Both allergens, Sola l 7 and Sola l 6, displayed primary structure differences with respect to their counterpart, Sola l 3, from tomato pulp/peel. They retained the ability to bind IgE from 71.4% of patients with severe symptoms. The purified proteins induced positive basophil activation test and skin prick test, and displayed cross-reactivity with homologous allergens from peanut and sunflower seeds, among others. CONCLUSION: We herein described two novel allergens from tomato seeds that belong to the nonspecific lipid transfer protein family classes 1 and 2, respectively. This is the first work associating IgE reactivity to these proteins with severe symptoms of certain tomato-allergic patients. Therefore, they are optimal candidates for clarifying the diagnosis of the tomato allergy.

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.

Identification of Sola l 4 as Bet v 1 homologous pathogenesis related-10 allergen in tomato fruits.

SCOPE: The aim was to investigate the potential contribution of a major birch pollen Bet v 1-homologous allergen to birch pollen-associated tomato fruit allergy. METHODS AND RESULTS: Two isoforms of a Bet v 1-homologous protein (designated Sola l 4) from tomato fruit were identified by cDNA-cloning and produced as recombinant proteins. Allergen-specific IgE levels to tomato, birch pollen, Bet v 1, and Sola l 4 were determined in birch pollen allergic patients with allergy or tolerance to tomato. Sola l 4 was recognized in 76% of birch/tomato allergic patients, while tomato- and Bet v 1-specific IgE was detectable in 64% and 81% of sera. Almost all patients sensitized to Bet v 1 reacted with Sola l 4. Both Sola l 4 isoforms displayed allergenic potency and IgE-cross-reactivity with Bet v 1 as investigated by competitive ELISA and in vitro mediator release assay. Nevertheless, the reactivity pattern of patients' sera was diverse. CONCLUSION: Sola l 4, a novel pathogenesis related-10 protein, qualifies as major allergen in tomato fruits. Data suggest Sola l 4 as class II allergen. IgE-testing using Sola l 4 showed low clinical specificity, but high sensitivity in tomato allergic patients and will further improve component-resolved allergy diagnosis.

Identification of putative new tomato allergens and differential interaction with IgEs of tomato allergic subjects.

BACKGROUND: Tomato became one of the world-wide most consumed vegetables, unfortunately accompanied by an increasing risk of tomato allergy affecting certain people. As tomato allergic subjects show highly variable reactions in clinical allergy tests, it is difficult to identify cultivars or differentially treated tomato plants where a significant reduction in the allergenic potential over all subjects of a cohort can be detected. OBJECTIVE: This study was carried out to test the hypothesis that individual variability is based on differential reactions of single subjects to particular allergens in tomato fruits of plants with certain genetic background or cultivated under distinct conditions. METHODS: Proteins were extracted from tomato fruits of the previously investigated genotypes 76R, its mycorrhizal mutant RMC, and the cultivar Counter, fertilized with different forms of nitrogen in deficit or excess. 2-D immunoblots were carried out with sera of nine tomato allergic subjects, beforehand analysed in skin prick tests. RESULTS: In total, ten putative tomato allergens were identified in these immunoblots. No correlation was detected between individual skin prick test results and the quantity of positive reactions to putative allergens. IgEs of each subject showed reactions to nearly every identified putative allergen, but reactions were dependent on genotype and growth conditions. Among the ten putative tomato allergens, five new candidates were identified as follows: an endo-ß-mannanase, a pectinacetylesterase, a pectinesterase inhibitor, an aspartyl protease family protein and a protein of unknown function. CONCLUSION AND CLINICAL RELEVANCE: The hypothesis that high interindividual differences in allergic reactions are based on the interactions between the IgEs of allergic subjects with particular allergens has to be rejected. However, five proteins with putative clinical relevance as tomato allergens could be newly identified.

Silencing ß1,2-xylosyltransferase in Transgenic Tomato Fruits Reveals xylose as Constitutive Component of Ige-Binding Epitopes.

Complex plant N-glycans containing ß1,2-xylose and core α1,3-fucose are regarded as the major class of the so-called "carbohydrate cross-reactive determinants" reactive with IgE antibodies in sera of many allergic patients, but their clinical relevance is still under debate. Plant glycosyltransferases, ß1,2-xylosyltransferase (XylT), and core α1,3-fucosyltransferase (FucT) are responsible for the transfer of ß1,2-linked xylose and core α1,3-linked fucose residues to N-glycans of glycoproteins, respectively. To test the clinical relevance of ß1,2-xylose-containing epitopes, expression of the tomato ß1,2-xylosyltransferase was down-regulated by RNA interference (RNAi) in transgenic plants. Fruits harvested from these transgenic plants were analyzed for accumulation of XylT mRNA, abundance of ß1,2-xylose epitopes and their allergenic potential. Based on quantitative real-time PCR analysis XylT mRNA levels were reduced up to 10-fold in independent transgenic lines as compared to untransformed control, whereas no xylosylated N-glycans could be revealed by MS analysis. Immunoblotting using anti-xylose-specific IgG antibodies revealed a strong reduction of ß1,2-xylose-containing epitopes. Incubating protein extracts from untransformed controls and XylT_RNAi plants with sera from tomato allergic patients showed a patient-specific reduction in IgE-binding, indicating a reduced allergenic potential of XylT_RNAi tomato fruits, in vitro. To elucidate the clinical relevance of ß1,2-xylose-containing complex N-glycans skin prick tests were performed demonstrating a reduced responsiveness of tomato allergic patients, in vivo. This study provides strong evidence for the clinical relevance of ß1,2-xylose-containing epitopes in vivo.