IgE-binding Capacity Research Articles

Molecular characterization, B-cell linear epitopes identification and key amino acids selection of the sesame allergen Ses i 5.

Ses i 5 is an important sesame allergen and no studies have been reported on the epitope identification of this allergen. Epitopes are the antigenic determinants on the surface of allergens, which are the basis of intensive study on protein antigenicity. In this paper, we analyzed the secondary structure, tertiary structure, hydrophilicity, antigenic index, flexibility, surface accessibility, and homology of the Ses i 5. In addition, we designed and synthesized overlapping peptides covering the entire amino acid sequence of Ses i 5, each overlapping peptide contains 15 amino acids with 5 amino acid repeats. The IgE binding capacity of each peptide was assessed by immune slot blot microarray. Ultimately, we identified seven B-cell linear epitopes of Ses i 5. Furthermore, the key amino acids of Ses i 5 were predicted and mutated to alanine, the changes in the IgE-binding capacity of the mutated peptides were assessed by indirect competition-ELISA (ic-ELISA). At last glycine 104 was identified as the key amino acid for IgE binding in Ses i 5. These studies will contribute to the deep study of molecular characterization and more information on epitopes of Ses i 5, which will benefit for the further understanding of the sesame allergen.

Effect of critical amino acids’ properties on potential allergenicity of Ara h 2 epitopes

ABSTRACT Peanuts are one of the most common allergenic foods in the world and can cause severe allergic reactions. Ara h 2 is the most allergenic components of peanut allergens. Although critical amino acids at the epitopes were identified, the effect of their physicochemical properties remained unclear. The critical amino acids in epitopes of Ara h 2 (epitope 1: 26ELQGDRRCQSQLER39 and epitope 2: 62RDPYSPSQDPYSPS75). The critical amino acids were substituted by amino acid with different physicochemical properties. Then, the potential allergenicity of those peptides was assessed by IgE binding and cell model. Changing the properties of amino acids by mutation affects potential sensitisation. The charge distribution and molecular weight of critical amino acids in the epitope affected the IgE binding capacity significantly. The conclusion based on peptide might be different from that on whole protein, and our study provided direction of amino acids mutation in desensitisation therapy.

Heat Treatment of Hazelnut Allergens Monitored by Polyclonal Sera and Epitope Fingerprinting.

Hazelnuts are frequently involved in IgE-mediated reactions and are the main cause of nut allergies in Europe. Most food products are processed before human consumption. Food processing can modify the structure, properties, and function of proteins, and as a result, the IgE-binding capacity of allergens can be affected. In this study, we aimed to investigate epitope changes caused by the roasting of hazelnuts using epitope fingerprinting. Rabbit sera were raised against hazelnut proteins, and their epitopes were characterized. Immunoassays using specific polyclonal antibodies from rabbits targeting the main allergens in hazelnuts revealed marked reductions in the levels of Cor a 1 (PR-10), Cor a 11 (7S globulin), and Cor a 14 (2S albumin). However, rabbit antibodies can recognize different epitopes. Using antibodies that are different and characterized could help establish reliable methods for estimating the effects of treatments on the allergenicity of foods. In this work, we provide the first practical application that could lead to sets of peptide epitopes to compare and standardize immune diagnostics, even for complex protein preparations.

Impact of Heat and Pressure Processing Treatments on the Digestibility of Peanut, Hazelnut, Pistachio and Cashew Allergens.

Food processing can alter protein biochemical properties, impacting immunoreactivity and allergenicity. A key feature of food allergens is their resistance to enzymatic digestion, particularly by pepsin and trypsin. This study compares the digestomes of raw and heat- and/or pressure-treated peanuts, hazelnuts, pistachios and cashews using the INFOGEST harmonized digestion protocol and analyzing their IgE-binding capacity through in vitro methods. Protein patterns from controls and digestomes were resolved by SDS-PAGE and tested with sera from allergic patients, confirmed by competitive ELISA for hazelnuts and peanuts. The results indicate that processing methods differently affect the gastrointestinal (GI) digestion of these allergens. Simulated GI digestion caused a significant destruction of protein structures, reducing but not eliminating IgE reactivity for all four nuts. Boiling for 60 min did not change the SDS-PAGE profiles, but it did stimulate enzymatic activity, decreasing IgE binding capacity. In contrast, applying heat and pressure led to a nearly complete inhibition of allergenic potential during simulated digestion. These findings suggest that employing intense food processing techniques and investigating the gastrointestinal effects of highly allergenic nuts could be crucial steps toward developing new hypoallergenic formulations.

Effect of pH-Shift Treatment on IgE-Binding Capacity and Conformational Structures of Peanut Protein.

Hypoallergenic processing is an area worthy of continued exploration. In the treatment of the peanut protein (PP), pH shift was applied by acidic (pH 1.0-4.0) and alkaline (pH 9.0-12.0) treatment, after which the pH was adjusted to 7.0. Following pH-shift treatment, PP showed a larger particle size than in neutral solutions. SDS-PAGE, CD analysis, intrinsic fluorescence, UV spectra, and surface hydrophobicity indicated the protein conformation was unfolded with the exposure of more buried hydrophobic residues. Additionally, the IgE-binding capacity of PP decreased after pH-shift treatment on both sides. Label-free LC-MS/MS results demonstrated that the pH-shift treatment induced the structural changes on allergens, which altered the abundance of peptides after tryptic digestion. Less linear IgE-binding epitopes were detected in PP with pH-shift treatment. Our results suggested the pH-shift treatment is a promising alternative approach in the peanut hypoallergenic processing. This study also provides a theoretical basis for the development of hypoallergenic food processing.

Development of Cashew and Pistachio Ladders through a Food-Processing Approach.

Following successful oral immunotherapy (OIT) for peanut allergy using boiled peanuts (BOPI trial), this study investigated the potential of wet-thermal-processing-induced allergen modification, specifically soaking and boiling (1-4 h) to reduce the allergenicity of cashew and pistachio allergens. In addition, this study provides a foundation of understanding for developing safer forms of cashew/pistachio administration for application in OIT by gradual exposure to increasing doses of modified allergens with reduced potency as an "allergen ladder". An SDS-PAGE analysis and an intrinsic-fluorescence spectroscopy revealed altered tertiary structures of the allergens, leading to their denaturation and even degradation. Notably, the reduction in both allergen-specific polyclonal IgG and human-specific IgE (sIgE) binding correlated with the treatment time, with the most significant decrease observed after 4 h of boiling. In contrast, shorter soaking treatments showed negligible effects on the IgE-binding capacity of these nuts, therefore indicating a further need for optimization. These findings indicate that extended boiling effectively reduced the amounts of the highly potent allergenic component Ana o 3 in cashew and Pis v 1 in pistachio, as confirmed by ELISA using polyclonal anti-Ana o 3 antibodies, and an immunoblot showed decreased IgE epitope binding in cashew and pistachio allergens, which further modified their allergenic profiles. This approach shows promise as a viable method for offering a safer therapeutic option for cashew/pistachio allergy.

Antigenicity elimination of ovalbumin by cold plasma-induced covalent binding with Gallic acid

The effect of cold plasma (CP) treatment in promoting the covalent grafting of ovalbumin (OVA) with gallic acid (GA) were investigated, along with identifying the binding sites in the OVA-GA complex and exploring its potential for reducing the antigenicity of OVA. The results showed that the GA content of 22.97 ± 1.27 mg/g in OVA-GA complex was obtained following 60 s of CP treatment. Using LC-MS/MS, four regions (T52-R59, V201-K207, I279-R285, and V281-K291) were identified, containing 12 GA binding sites in the OVA-GA complex. Additionally, a significant reduction in IgE binding capacity (70.83 ± 0.90 %) was observed, as confirmed by ELISA analysis. The masking/steric-hindrance effect on linear epitopes and the disruption of conformational epitopes of OVA as a result of GA grafting may be the key factors leading to the reduction in OVA antigenicity. This study highlights that promoting the grafting of polyphenols onto proteins using CP treatment is an effective strategy for reducing the antigenicity of protein allergens.

Effect of enzymatic hydrolysis and ultrasound pretreatment on allergenicity, functional properties and bioactivity of whey protein isolates

Whey protein isolate (WPI) is an important food ingredient and a major allergen in food. Enzymatic hydrolysis is an important method for WPI modification, but there is limited information on the effect of ultrasound pretreatment on WPI hydrolysates (WPH). The aim of this study was to analyze the effect of enzymatic hydrolysis and ultrasound pretreatment on the allergenicity, functional properties and bioactivity of WPH by multispectroscopy and peptidomics combined with bioinformatics. The results showed that ultrasound pretreatment contributed to the production of WPH with low allergenicity (IgE binding capacity is 55.59%) and good functional properties (emulsifying activity index is 27.02%, foaming characteristic is 50.00%) and bioactivity (total antioxidant capacity is 65.94%). This was attributed to the synergistic hydrolysis of WPI by endopeptidases and exopeptidases, and ultrasound pretreatment that altered the accessibility of WPI to proteases and the peptide profiles and main proteins of WPH, affecting the changes in their spatial and primary structure. This research will advance the application of WPI in hypoallergenic foods.

Modulating allergenicity of prawn tropomyosin (penaeus chinensis) via pulsed electric field-induced conformational changes

The effect of electric field intensities (EFIs, 5–20 kV/cm) and treatment times (0.5–2 h) on allergenicity and spatial conformation of prawn tropomyosin was evaluated. The results demonstrated that the IgG and IgE binding capacity of tropomyosin maximally increased by 24.34 % and 29.16 % respectively, followed by a subsequent decrease after 20 kV/cm treatment for 1 h. Interestingly, 5–10 kV/cm treatments significantly decreased the α-helix content (P < 0.05) and fluorescence intensity, while 20 kV/cm treatment promoted extensive spiralization, resulting in a tightly packed structure. The increased flexibility further exposed the hydrolysis sites and strengthened the gastrointestinal digestibility of tropomyosin. Additionally, molecular dynamic simulation indicated that extended EFIs increased structural flexibility and depolymerized the tropomyosin dimers through destroying intermolecular hydrogen bonds (formed within arginine and glutamate), which allowed tropomyosin to be easily recognized by IgG/IgE. Whereas, decrease of solvent-accessibility surface area (SASA), hydrophobic surface area induced conformation folded and caused epitopes masked.

Characterization, Epitope Confirmation, and Cross-Reactivity Analysis of Parvalbumin from Lateolabrax maculatus by Multiomics Technologies.

Spotted seabass (Lateolabrax maculatus) is the second largest maricultural fish species in China and is the main trigger of food-related allergic reactions. Nevertheless, studies on the allergens of L. maculatus are limited. This study aimed to characterize pan-allergen parvalbumin from L. maculatus. Two proteins of about 11 kDa were purified and confirmed as parvalbumins by mass spectrometry. The IgG- and IgE-binding activities were evaluated through an immunoblotting assay. The molecular characteristics of β-parvalbumin were investigated by combining proteomics, genomics, and immunoinformatics approaches. The results indicated that β-parvalbumin consists of 109 amino acids with a molecular weight of 11.5 kDa and is the major allergen displaying strong IgE-binding capacity. In silico analysis and a dot blotting assay confirmed seven linear B cell epitopes distributed mainly on α-helixes and the calcium-binding loops. In addition, the cross-reactivity among 26 commonly consumed fish species was analyzed. The in-house generated anti-L. maculatus parvalbumin polyclonal antibody recognized 100% of the 26 fish species, demonstrating cross-reactivity and better binding capacity than the anticod parvalbumin antibody. Together, this study provides an efficient protocol to characterize allergens with multiomics methods and supports parvalbumin from L. maculatus as a candidate for fish allergen determination and allergy diagnosis.

Pseudomonas aeruginosa exotoxin A as a novel allergen induced Non-TH2 inflammation in a murine model of steroid-insensitive asthma

BackgroundDespite the immediate in vivo occurrence of anaphylactic and allergic reactions following treatment with Pseudomonas aeruginosa exotoxin A (PEA)-based immunotoxins, the immunological role of PEA in asthma pathogenesis remains unclear. ObjectiveThis study investigated the allergenic potential of PEA and the specific type of asthma induced. MethodsRecombinant PEA (rPEA) lacking domain Ia (to eliminate non-specific cytotoxicity) was expressed, purified, and employed to detect serum PEA-specific IgE levels in asthmatic patients. Competitive ELISA assays were used to assess rPEA's IgE binding capacity and allergenicity. Additionally, rPEA-challenged C57BL/6 mice were subjected to inflammatory endotyping and therapeutic assays to characterize the allergic nature of PEA. ResultsPEA-specific IgE was identified in 17 (14.2 %) of 120 asthma patients. The rPEA-sensitized and challenged mice had increased PEA-specific immunoglobulins (such as IgE, IgG1 and IgG2a) and developed asthma-like phenotypes with airway hyperresponsiveness, severe airway inflammation, and airway remodeling. Lungs from these mice displayed significant increases in neutrophils and IL-17A+ cells. Innate lymphoid cells (ILCs) produced type 2 cytokines (IL-4, IL-5, and IL-13), whereas Th cells did not. Nonetheless, airway inflammation, rather than hyperresponsiveness, was elicited in non-sensitized mice upon challenge with rPEA. Importantly, rPEA-induced asthmatic mice were unresponsive to dexamethasone treatment. ConclusionPEA is a novel allergen that sensitizes asthmatic patients. Furthermore, mice developed steroid-resistant asthma, characterized by an atypical cytokine profile associated with non-TH2 inflammation, only after being sensitized and challenged with rPEA. These findings suggest a potentially significant role for PEA in asthma development, warranting consideration in clinical diagnosis and treatment strategies.

Maillard reaction affecting immunobinding activity and digestibility of tropomyosin in Alectryonella plicatula food matrix

In recent years, the allergy rate of oysters has surged, and daily food processing methods make it hard to reduce heat resistance and digestive allergy such as tropomyosin (TM). In this study, the Maillard reaction with xylose (Xyl) significantly reduced the IgE binding capacity of Alectryonella plicatula food matrix (AFM), that reduced by (77.81 ± 2.68)%. The study found the Maillard reaction changes the structure of the AFM, in which the content of α-helix decreased by (24.64 ± 1.46)%. Structural transformation further explains why the Maillard reaction alters the immunobinding activity of AFM. In addition, the Maillard reaction reduces the digestive stability of the AFM and makes TM in the A. plicatula food matrix Maillard reaction products (AFM-MRPs) more easily digested. Based on the above research, 10 amino acids on the 7 IgE epitopes of TM were modified. This result indicates that the Maillard reaction reduces the immunobinding activity of the AFM by changing the structure and modifying the amino acids on the epitope.

Electrophoresis analysis and specific IgE-binding capacity of C18 unsaturated fatty acid-milk protein complexes during in vitro gastrointestinal digestion

The main whey allergenic proteins in bovine milk are α-lactalbumin (BLA) and β-lactoglobulin (BLG). When people consume bovine milk, BLA and BLG bind to C18 unsaturated fatty acids (UFA) in the matrix and form fatty acid-milk protein complexes. In this study, we explored the digestive stability of fatty acid-milk protein complexes by simulating infant and adult gastrointestinal digestion conditions and assessed the effects of C18 UFA on milk protein allergenicity. Our findings revealed that the optimal pH digestion for milk proteins in infants and adults was pH 3.0 and pH 2.0, respectively. The tricine-SDS-PAGE and IgE-binding capacity results revealed that the complexes were not easily degraded during digestion resistance, and the digestion products had strong IgE-binding capacity. Therefore, C18 UFA make milk proteins resistant to digestion, thereby increasing their allergenicity.

Effects of ultrasound pretreatment on the structure, IgE binding capacity, functional properties and bioactivity of whey protein hydrolysates via multispectroscopy and peptidomics revealed

Whey protein is an important food ingredient, but it is also considered a major food allergen. The aim of this study was to investigate the effect of ultrasound pretreatment on the structure, IgE binding capacity, functional properties and biological activity of whey protein isolate (WPI) hydrolysates (WPH), including WPI hydrolyzed by a combination of enzymes from Bromelain and ProteAXH (BA-WPI) and WPI hydrolyzed by a combination of enzymes from Papain W-40 and ProteAXH (PA-WPI). The IgE binding capacity of BA-WPI and PA-WPI was reduced to 40.28% and 30.17%, respectively, due to disruption/exposure/shielding of conformational and linear epitopes. The IgE binding capacity of sonicated WPI was increased, but ultrasound pretreatment further reduced the IgE binding capacity of the hydrolysates to 32.89% and 28.04%. This is due to the fact that ultrasound pretreatment leads to conformational changes including increased α-helix and β-sheet structure, exposure of aromatic amino acids, surface hydrophobicity, and increased sulfhydryl content, which increases the accessibility of allergenic epitopes to WPI by the enzyme. Multispectral and LC-MS/MS results further indicated that ultrasound pretreatment altered the conformational and primary structural changes of the hydrolysates. The thermograms showed that ultrasound pretreatment mainly altered the epitope spectra of β-lactoglobulin hydrolysates, while it had less effect on the epitope spectra of α-lactalbumin hydrolysates. Additionally, ultrasound pretreatment significantly improved the foaming properties, antioxidant activity, and α-glucosidase inhibition of the hydrolysates without impairing the solubility and emulsification properties of the hydrolysates. Therefore, ultrasound pretreatment is a feasible method to reduce the allergenicity of WPH and to improve their functional properties and bioactivity. Notably, ultrasonic pretreatment improved the effectiveness and efficiency of WPI hydrolysis, which is a feasible method to produce high-quality protein feedstock in a green, efficient, and economical way.

Reducing the Allergenicity of β-Lactoglobulin by Covalent Modification with Different Contents of Epigallocatechin Gallate (EGCG): In Vitro and In Vivo Studies.

β-Lactoglobulin (βLG) is a major allergen in bovine milk protein. This study was designed to investigate changes in βLG structure, digestibility, and allergenicity induced by covalent binding modification with different contents of (-)-epigallocatechin 3-gallate (EGCG). The reaction of EGCG conjugation with βLG reached saturation at a molar ratio of 1:60 βLG:EGCG. Conjugation with EGCG altered the βLG structure, decreased IgE-binding capacity, and increased digestibility in a dose-dependent manner. In vivo studies showed that covalent conjugation with EGCG can reduce βLG-induced allergic symptoms with reducing levels of IgE, histamine, and mast cell protease-1 (mMCP-1) and the percentage of sensitized mast cells. Allergenicity was reduced more effectively in saturated βLG-EGCG conjugates compared to semisaturated conjugates. Observed changes in IFN-γ, IL-4, IL-5, IL-10, and TGF-β levels suggested that βLG-EGCG conjugates were able to promote Th1/Th2 immune balance. These findings further our understanding of the relationship between the degree of polyphenol conjugation and the allergenicity of food allergens.

Mould allergen Alt a 1 spiked with the micronutrient retinoic acid reduces Th2 response and ameliorates Alternaria allergy in BALB/c mice.

We investigated the biological function of the mould allergen Alt a 1 as a carrier of micronutrients, such as the vitamin A metabolite retinoic acid (RA) and the influence of RA binding on its allergenicity invitro and invivo. Alt a 1-RA complex formation was analyzed in silico and invitro. PBMCs from Alternaria-allergic donors were stimulated with Alt a 1 complexed with RA (holo-Alt a 1) or empty apo-Alt a 1 and analyzed for cytokine production and CD marker expression. Serum IgE-binding and crosslinking assays to apo- and holo-protein were correlated to B-cell epitope analysis. Female BALB/c mice already sensitized to Alt a 1 were intranasally treated with apo-Alt a 1, holo-Alt a 1 or RA alone before measuring anaphylactic response, serum antibody levels, splenic cytokines and CD marker expression. In silico docking calculations and invitro assays showed that the extent of RA binding depended on the higher quaternary state of Alt a 1. Holo-Alt a 1 loaded with RA reduced IL-13 released from PBMCs and CD3+CD4+CRTh2 cells. Complexing Alt a 1 to RA masked its IgE B-cell epitopes and reduced its IgE-binding capacity. In a therapeutic mouse model of Alternaria allergy nasal application of holo-Alt a 1, but not of apo-Alt a 1, significantly impeded the anaphylactic response, impaired splenic antigen-presenting cells and induced IL-10 production. Holo-Alt a 1 binding to RA was able to alleviate Th2 immunity invitro, modulate an ongoing Th2 response and prevent anaphylactic symptoms invivo, presenting a novel option for improving allergen-specific immunotherapy in Alternaria allergy.

Effects of Chlorogenic Acid on Lowering IgE-Binding Capacity of Soybean 7S: Comparison between Covalent and Noncovalent Interaction.

Allergenicity of soybean 7S protein (7S) troubles many people around the world. However, many processing methods for lowering allergenicity is invalid. Interaction of 7S with phenolic acids, such as chlorogenic acid (CHA), to structurally modify 7S may lower the allergenicity. Hence, the effects of covalent (C-I, periodate oxidation method) and noncovalent interactions (NC-I) of 7S with CHA in different concentrations (0.3, 0.5, and 1.0 mM) on lowering 7S allergenicity were investigated in this study. The results demonstrated that C-I led to higher binding efficiency (C-0.3:28.51 ± 2.13%) than NC-I (N-0.3:22.66 ± 1.75%). The C-I decreased the α-helix content (C-1:21.06%), while the NC-I increased the random coil content (N-1:24.39%). The covalent 7S-CHA complexes of different concentrations had lower IgE binding capacity (C-0.3:37.38 ± 0.61; C-0.5:34.89 ± 0.80; C-1:35.69 ± 0.61%) compared with that of natural 7S (100%), while the noncovalent 7S-CHA complexes showed concentration-dependent inhibition of IgE binding capacity (N-0.3:57.89 ± 1.23; N-0.5:46.91 ± 1.57; N-1:40.79 ± 0.22%). Both interactions produced binding to known linear epitopes. This study provides the theoretical basis for the CHA application in soybean products to lower soybean allergenicity.

Structural and Immunological Features of PR-10 Allergens: Focusing on the Major Alder Pollen Allergen Aln g 1.

Today, allergies have become a serious problem. PR-10 proteins are clinically relevant allergens that have the ability to bind hydrophobic ligands, which can significantly increase their allergenicity potential. It has been recently shown that not only the birch pollen allergen Bet v 1 but also the alder pollen allergen Aln g 1, might act as a true sensitizer of the immune system. The current investigation is aimed at the further study of the allergenic and structural features of Aln g 1. By using qPCR, we showed that Aln g 1 was able to upregulate alarmins in epithelial cells, playing an important role in sensitization. With the use of CD-spectroscopy and ELISA assays with the sera of allergic patients, we demonstrated that Aln g 1 did not completely restore its structure after thermal denaturation, which led to a decrease in its IgE-binding capacity. Using site-directed mutagenesis, we revealed that the replacement of two residues (Asp27 and Leu30) in the structure of Aln g 1 led to a decrease in its ability to bind to both IgE from sera of allergic patients and lipid ligands. The obtained data open a prospect for the development of hypoallergenic variants of the major alder allergen Aln g 1 for allergen-specific immunotherapy.

Modification of structure, epitope and allergenicity on heat-stressed ovalbumin by resveratrol

Allergen modification is a novel strategy for preventing and treating food allergy. Resveratrol (RES) can be used as a modifying ligand for allergens, but the interaction mechanism between RES and allergens is still not detailed, and the ramifications of this interaction on the structure, epitope and allergenicity of allergens are also lacking a clear explanation. In addition, the application of heat can promote protein structure to unfold and expose more binding sites to facilitate interaction. Therefore, in this study, ovalbumin (OVA) was selected as the allergen model and was heated to expose more binding sites. The effects of the interaction between RES and heat-stressed ovalbumin (HOVA) on allergen structure, epitope and allergenicity were investigated by combining routine experimental analysis and computer simulation. Results showed heat stress at 323 K for 15 min could better unfold the molecular structure of OVA. On this basis, the interaction between RES and OVA was strengthened, which showed a static quenching of the ground state complex with binding affinity of 1.25 × 106 L/mol. The binding of RES induced the variation of protein microenvironment, and the overall structure tended to disordered direction. Computer simulation had shown RES could directly act on the IgE epitope region (AA251-260) of the OVA. The allergenicity evaluation experiment further indicated the combination of RES alleviated the IgE binding capacity of HOVA. These findings are helpful to further study the mechanism of RES ligand modification to change food allergy.

Tyrosine nitration enhances the allergenic potential of house dust mite allergen Der p 2

Nitration of allergenic proteins caused by atmospheric pollutants O3 and NO2 may enhance their allergenic potential. In the study, the influence of nitration was investigated on the allergenicity of Der p 2, which is a main allergen from house dust mites and plays an important role in allergenic rhinitis and asthma. The results reveal that nitrated Der p 2 enhanced the IgE-binding capacity, upregulated the mRNA expression and release of IL-6 and IL-8 from bronchial epithelial cells, and induced higher levels of specific-IgE, TH2 cytokines and white blood cells in mice. Besides, nitrated Der p 2 caused more severe oxidative stress and allergenic symptoms in mice. It is concluded that nitration enhanced the allergenicity of Der p 2 through not only directly inducing higher amount of specific-IgE and stronger responses of TH2 cytokines, but also indirectly aggravating allergic symptoms by oxidative stress and adjuvant-like activation airway epithelial cells. The study suggests that the contribution of nitration to the promotion in allergenicity should not be ignored when precisely assessing the risk of house dust mite allergens in real environment.