Molecular and Immunological Identification of Low Allergenic Fruits among Old and New Apple Varieties

About 50–70% of patients allergic to birch pollen suffer from sensitization after apple ingestion. Apple allergenicity was established in only few varieties. Studies were performed on apple fruits of 21 traditional and nine modern varieties organically, intensively, or integratively produced. The aim of the study was to assess whether the factors like cultivation method, maturity stage, genotype, or type of tissue place an impact on the allergenic potential of apples. To answer these questions, we used semiquantitative real-time PCR, ELISA, and immunoblotting. Apple allergen genes present divergent expression across apple cultivars. Expression of the Mal d 1.06A correlates with the Mal d 1 level and is affected by the cultivation method and maturity of the fruit. The content of the main allergen Mal d 1 varied widely across cultivars. Interestingly, in our study, the Gala variety presented a low Mal d 1 concentration regardless of the cultivation method. Based on the Mal d 1.06A expression, the Mal d 1 protein content, and the immunoreactivity assay, the Kandil Sinap, Kosztela, Rumianka from Alma-Ata, Kantówka Gdańska, Reinette Coulon, and Gala cultivars emerged as potentially hypoallergenic apple cultivars. Our study allowed distinguishing between potentially low, medium, and highly allergenic varieties.     

DNA Methylation Levels in Mononuclear Leukocytes from the Mother and Her Child Are Associated with IgE Sensitization to Allergens in Early Life

DNA methylation changes may predispose becoming IgE-sensitized to allergens. We analyzed whether DNA methylation in peripheral blood mononuclear cells (PBMC) is associated with IgE sensitization at 5 years of age (5Y). DNA methylation was measured in 288 PBMC samples from 74 mother/child pairs from the birth cohort ALADDIN (Assessment of Lifestyle and Allergic Disease During INfancy) using the HumanMethylation450BeadChip (Illumina). PBMCs were obtained from the mothers during pregnancy and from their children in cord blood, at 2 years and 5Y. DNA methylation levels at each time point were compared between children with and without IgE sensitization to allergens at 5Y. For replication, CpG sites associated with IgE sensitization in ALADDIN were evaluated in whole blood DNA of 256 children, 4 years old, from the BAMSE (Swedish abbreviation for Children, Allergy, Milieu, Stockholm, Epidemiology) cohort. We found 34 differentially methylated regions (DMRs) associated with IgE sensitization to airborne allergens and 38 DMRs associated with sensitization to food allergens in children at 5Y (Sidak p ≤ 0.05). Genes associated with airborne sensitization were enriched in the pathway of endocytosis, while genes associated with food sensitization were enriched in focal adhesion, the bacterial invasion of epithelial cells, and leukocyte migration. Furthermore, 25 DMRs in maternal PBMCs were associated with IgE sensitization to airborne allergens in their children at 5Y, which were functionally annotated to the mTOR (mammalian Target of Rapamycin) signaling pathway. This study supports that DNA methylation is associated with IgE sensitization early in life and revealed new candidate genes for atopy. Moreover, our study provides evidence that maternal DNA methylation levels are associated with IgE sensitization in the child supporting early in utero effects on atopy predisposition.     

INACTIVATION OF PAPAIN PROTEOLYTIC ACTIVITY IN THE PRESENCE OF ASCORBIC ACID AND CU++ IONS

The simultaneous presence of ascorbic acid, Cu⁺⁺ ions and oxygen causes reversible inactivation of proteolytic activity of papain. Low concentrations of ascorbic acid and Cu⁺⁺ ions have no effect on their own. Ascorbic acid at concentrations higher than 2 × 10⁻⁴ m inactivates papain irreversibly in the presence of Cu⁺⁺ ions. Papain inactivation is not accompanied by the destruction of papain molecules. Irreversible papain inactivation does not occur in solutions free of oxygen and the intermediates of ascorbic acid oxidation, i.e. dehydroascorbic acid and hydrogen peroxide, do not cause papain inactivation. The irreversible inactivation of papain is most probably due to free radicals formed during ascorbic acid oxidation. Owing to the possible occurrence of both ascorbic acid and Cu⁺⁺ ions in beer, partial irreversible inactivation of papain can be expected even at very low oxygen concentrations.     

Tropomyosin Contains IgE‐Binding Epitopes Sensitive to Periodate but Not to Enzymatic Deglycosylation

Glycosylation has been reported to affect the epitopes of food allergens, however, there are few reports on its role in crab allergen. In the present study, the effect of glycosylation on the IgE‐binding activity of tropomyosin (TM), a major allergen in Scylla paramamosain, was investigated. The results showed that TM was a glycoprotein with a 0.2% carbohydrate moiety and contained O‐glycan. Moreover, enzymatic deglycosylation of TM by glycosidase had no effect on the IgE‐binding activity of TM. In contrast, treatment with periodate resulted in a significant reduction in its IgE‐binding activity.     

The clinical and immunomodulatory effects of green soybean extracts

The present study was performed to investigate the immune-modulating activities of extracts from green soybean (Glycine max) in a 2,4-toluene diisocyanate (TDI)-inducing guinea pig rhinitis model and a human trial study for allergic rhinitis. Hot water extracts of green soybean were chosen for animal experimentation on the basis of their ability to regulate the production of B cell-activating factor of the TNF family and a proliferation-inducing ligand in mouse spleen cells. Green soybean extracts significantly decreased the levels of ovalubumin (OVA)-specific IgE in mice and significantly suppressed the TDI-induced nasal mucosa secretion. An open-label human pilot study was performed on 16 subjects, using Japanese cedar pollinosis. The symptom scores for Japanese cedar pollinosis were better in the long-term green soybean extracts intake group than in the withdrawal short-term intake group. Green soybean extracts had great potential as an orally active immune modulator for the treatment of various allergic diseases.     

辐照对Pen a1抗原表位免疫原性的影响

辐照处理刀额新对虾中主要过敏原Pen a1,采用SDS-PAGE,MOLDI-TOF MS方法分析辐照处理对虾致敏蛋白Pen a1分子质量的影响,同时利用表位抗体进行免疫印迹及间接竞争ELISA法评估Pen a1中5种抗原表位免疫原性的变化情况。结果显示:与未处理相比,6.7 k Gy辐照处理能够破坏部分Pen a1蛋白结构,导致裂解和聚合现象的发生。5种抗原表位免疫原性均未降低,并有不同程度的增加,其中Epitope1,2,3,4的IC50值约为对照的4/5,Epitope5的IC50值变化不大,说明其对辐照处理较稳定。低剂量的辐照处理不能降低Pen a1抗原表位的免疫原性。     

Ferulic acid enhances IgE binding to peanut allergens in Western blots

Ferulic acid, a phenolic compound, is known to complex with proteins and peanut allergens. Preliminary studies indicated that ferulic acid could also complex with and inhibit IgE antibodies to peanut allergens in ELISA. However, results from Western blots were quite different. The objective of this study was to report the unexpected finding of IgE binding being enhanced rather than reduced by ferulic acid in Western blot. Ferulic acid, at various concentrations (0–10 mg/ml), was mixed with a pooled plasma (containing IgE antibodies) from peanut-allergic individuals before incubation with a peanut allergen-bound membrane and colorimetric detection of IgE. Results showed that an enhancement of allergen bands or IgE binding, compared to the control, was observed at a ferulic concentration of 10 mg/ml. Compounds with a similar structure, such as caffeic acid and chlorogenic acid, at the same concentration, did not have an enhancing effect on IgE binding. Tests with ferulic acid alone or soy proteins indicated that the enhanced IgE binding was due to the IgE–ferulic complexes and not ferulic acid itself. It was concluded that ferulic acid (10 mg/ml), in combination with IgE, enhanced IgE binding to peanut allergens in Western blots. The finding indicated that ferulic acid can help reduce the time for colour development of protein bands in Western blots.