Allergenicity and antigenicity of chicken egg ovomucoid (Gal d III) compared with ovalbumin (Gal d I) in children with egg allergy and in mice

Generation of an Ovomucoid-Immune scFv Library for the Development of Novel Immunoassays in Hen's Egg Detection

Hen's egg allergy is the second most common food allergy among infants and young children. The possible presence of undeclared eggs in foods poses a significant risk to sensitized individuals. Therefore, reliable egg allergen detection methods are needed to ensure compliance with food labeling and improve consumer protection. This work describes for the first time the application of phage display technology for the generation of a recombinant antibody aimed at the specific detection of hen's ovomucoid. First, a single-chain variable fragment (scFv) library was constructed from mRNA isolated from the spleen of a rabbit immunized with ovomucoid. After rounds of biopanning, four binding clones were isolated and characterized. Based on the best ovomucoid-binding candidate SR-G1, an indirect phage enzyme-linked immunosorbent assay (phage-ELISA) was developed, reaching limits of detection and quantitation of 43 and 79 ng/mL of ovomucoid, respectively. The developed ELISA was applied to the analysis of a wide variety of food products, obtaining a good correlation with a commercial egg detection assay used as a reference. Finally, in silico modeling of the antigen-antibody complex revealed that the main interactions most likely occur between the scFv heavy chain and the ovomucoid domain-III, the most immunogenic region of this allergen.

Transcription activator-like effector nuclease-mediated deletion safely eliminates the major egg allergen ovomucoid in chickens

Among the major egg allergens, ovomucoid (OVM) is very stable against heat and digestive enzymes, making it difficult to remove physiochemically and inactivate allergens. However, recent genome editing technology has made it possible to generate OVM-knockout chicken eggs. To use this OVM-knockout chicken egg as food, it is important to evaluate its safety as food. Therefore, in this study, we examined the presence or absence of mutant protein expression, vector sequence insertion, and off-target effects in chickens knocked out with OVM by platinum TALENs. The eggs laid by homozygous OVM-knockout hens showed no evident abnormalities, and immunoblotting showed that the albumen contained neither the mature OVM nor the OVM truncated variant. Whole genome sequencing (WGS) revealed that the potential TALEN-induced off-target effects in OVM-knockout chickens were localized in the intergenic and intron regions. The WGS information confirmed that plasmid vectors used for genome editing were only transiently present and did not integrate into the genome of edited chickens. These results indicate the importance of safety evaluation and reveal that the eggs laid by this OVM knockout chicken solve the allergy problem in food and vaccines.

Phenotyping of immediate-type food allergies based on 10 years of research: A latent class analysis

BACKGROUND

Food allergy is a disease with a diverse and variable natural history, and some patients may react to two or more food antigens. This study aimed to classify and characterize the long-term prognosis of infantile-onset, immediate-type food allergies, focusing on three major antigens in Japan: egg, milk, and wheat.

METHODS

All children who visited our hospital with food allergies, including suspected cases, were prospectively registered in our medical database. Among the children in this database, subjects registered by the age of 1 year with immediate-type symptoms or sensitization to the above three antigens were included. The course of the subjects up to the age of 6 years was analyzed. Cox regression analysis and repeated-measures latent class analysis (LCA) were performed to reveal risk factors and tolerance patterns for food allergies.

RESULTS

We included 915 patients with immediate-type food allergy symptoms and 276 sensitized asymptomatic patients in this study. The number of patients with immediate-type symptoms to egg, milk, and wheat was 609, 443, and 235, respectively. The number of patients with multiple food allergies was 302. The proportion of patients with tolerance to egg, milk, and wheat at 6 years of age was 74%, 69%, and 75%, respectively. LCA revealed 7 classes of prognosis for food allergies. The largest class was transient egg allergy alone (19.6%), and there were severe cases of multiple food allergies (6.5%).

CONCLUSIONS

This study demonstrated the prognosis of food allergy classes in Japan, including multiple food allergies, with 7 classes with its own characteristics.

Novel nanocomposite of spiky-shaped gold nanourchins/ titanium dioxide/nafion for amplified signal and efficient electrochemiluminescence detection of ovomucoid

This work reports on the first electrochemiluminescence (ECL) immunosensor employing a novel nanostructured composite of titanium dioxide (TiO₂) and gold nanourchins (AuNU) to detect protein allergen Ovomucoid (Ovm) found in eggs. TiO₂ and AuNU were dispersed in Nafion and drop-casted onto SPGE with Tris(2,2'-bipyridyl)-ruthenium (II) ([Ru(bpy)₃]²⁺) and tri-n-propylamine (TPrA) served as strong luminophore/co-reactant pairs as a source of ECL signals. The linear range, limit of detection, reproducibility and practical applications of the sensor were assessed. The fabricated ECL immuosensor produced a promising limit of detection of as low as 0.01 pg/mL. Two linear ranges of 0.01-50 pg/mL and 100-750 pg/mL with corresponding correlation coefficients of R² = 0.99136 and R² = 0.97829) respectively, were determined. Despite its simple fabrication method, this label-free immunosensor also showcased excellent selectivity, reproducibility, interference-resistance and yielded outstanding recoveries between 97.42 and 104.05% of Ovm analysis in spiked real food samples.

Bisdemethoxycurcumin attenuates OVA‑induced food allergy by inhibiting the MAPK and NF‑κB signaling pathways

Bisdemethoxycurcumin (BDMC) is an important ingredient derived from turmeric in addition to curcumin. It has been reported that BDMC can be used to treat mast cell-mediated allergic diseases. In the present study, a food allergy (FA) murine model sensitized by intraperitoneal injection followed by oral challenge with ovalbumin (OVA) was established. BDMC was orally administered at 100 and 200 mg/kg for 11 days in the challenge phase to treat OVA-induced FA mice. FA symptoms such as diarrhea score, anaphylactic symptom score and rectal temperature were recorded. Intestinal tissue was also observed by hematoxylin and eosin staining. In addition, other allergic indicators were also analyzed by ELISA and western blot analysis. The present study demonstrated that BDMC could suppress the decreases in rectal temperature, diarrhea and anaphylactic symptoms in FA mice. BDMC could also ameliorate the inflammation of intestinal tissues in FA mice. BDMC not only decreased the production of OVA-specific immunoglobulin (OVA-sIg)E, IgG1, histamine, mouse mast cell protease-1, diamine oxidase, cytokines (IL-4, IL-5 and IL-13) but increased cytokines interferon-γ production. The protein expression results showed that the levels of Gata-3 were decreased but T-bet levels were increased. Furthermore, compared with the OVA group, phosphorylated (p)-p38, p-JNK, p-ERK and p-NF-κBp65 levels were decreased and p-IκBα level was increased. In conclusion, the results showed that BDMC possessed a protective effect on FA. Furthermore, BDMC was able to regulate the T-helper cells (Th)1/Th2 immune balance and inhibit the activation of MAPK and NF-κB pathways in FA mice.

Precision medicine in the allergy clinic: the application of component resolved diagnosis

INTRODUCTION

A precise diagnosis is key for the optimal management of allergic diseases and asthma. In vivo or in vitro diagnostic methods that use allergen extracts often fail to identify the molecules eliciting the allergic reactions.

AREAS COVERED

Component-resolved diagnosis (CRD) has solved most of the limitations of extract-based diagnostic procedures and is currently valuable tool for the precision diagnosis in the allergy clinic, for venom and food allergy, asthma, allergic rhinitis, and atopic dermatitis. Its implementation in daily practice facilitates: a) the distinction between genuine multiple sensitizations and cross-reactive sensitization in polysensitized patients; b) the prediction of a severe, systemic reaction in food or insect venom allergy; c) the optimal selection of allergen immunotherapy based on the patient sensitization profile. This paper describes its main advantages and disadvantages, cost-effectiveness and future perspectives.

EXPERT OPINION

The diagnostic strategy based on CRD is part of the new concept of precision immunology, which aims to improve the management of allergic diseases.

Suppression of Hippo Pathway by Food Allergen Exacerbates Intestinal Epithelia Instability and Facilitates Hypersensitivity

SCOPE

Hippo signaling is a crucial pathway in innate immune responses, but the relationship between food allergy and Hippo pathway is unknown. The aim of this work is to investigate the regulation of food allergy by Hippo pathway and reveal the molecular mechanisms.

METHODS AND RESULTS

Two food allergens tropomyosin and ovalbumin are used to challenge a mouse model and CMT93 intestinal epithelia cell model. The allergic responses and the activation of Hippo pathway are tested in these models. In the mouse model, both allergens trigged significant allergic responses, and Hippo pathway is suppressed after allergen challenge. In CMT93, both allergens upregulate the expression of allergic cytokines thymic stromal lymphopoietin, interleukin (IL)-25, and IL-33. In TAZ KD CMT93, the Hippo pathway is blocked, and the expression of allergenic cytokines are also suppressed.

CONCLUSIONS

Both in vivo and in vitro data demonstrate that the two food allergens suppressed Hippo pathway by downregulating TAZ expression, resulting in intestinal epithelia instability, and finally leading to hypersensitivity reactions. These findings provide potential therapeutic targets and molecular markers for food allergy, and provide dietary guidelines for allergenic individuals.

Production and characterization of eggs from hens with ovomucoid gene mutation

Ovomucoid is a major egg white protein which is considered as the most dominant allergen in chicken eggs. Owing to the difficulty of separating ovomucoid from egg whites, researchers have adopted genetic deletion for development of hypoallergenic eggs. Previously, we used CRISPR/Cas9 to establish chickens with ovomucoid gene (OVM) mutations, but it remained unknown whether such hens could produce eggs at maturity. Here, we have reported on eggs laid by OVM-targeted hens. Except for watery egg whites, the eggs had no evident abnormalities. Real-time PCR revealed alternative splicing of OVM mRNA in hens, but their expression was limited. Immunoblotting detected neither mature ovomucoid nor ovomucoid-truncated splicing variants in egg whites. Sixteen chicks hatched from 28 fertilized eggs laid by OVM-targeted hens, and fourteen of the sixteen chicks demonstrated healthy growth. Taken together, our results demonstrated that OVM knockout could almost completely eliminate ovomucoid from eggs, without abolishing fertility. Thus, the eggs developed in this study have potential as a hypoallergenic food source for most patients with egg allergies.

Ovomucoid epitope-specific repertoire of IgE, IgG4 , IgG1 , IgA1 , and IgD antibodies in egg-allergic children

BACKGROUND

Egg-white ovomucoid, that is, Gal d 1, is associated with IgE-mediated allergic reactions in most egg-allergic children. Epitope-specific IgE levels have been correlated with the severity of egg allergy, while emerging evidence suggests that other antibody isotypes (IgG₁ , IgG₄ , IgA, and IgD) may have a protective function; yet, their epitope-specific repertoires and associations with atopic comorbidities have not been studied.

METHODS

Bead-based epitope assay (BBEA) was used to quantitate the levels of epitope-specific (es)IgA, esIgE, esIgD, esIgG₁ , and esIgG₄ antibodies directed at 58 (15-mer) overlapping peptides, covering the entire sequence of ovomucoid, in plasma of 38 egg-allergic and 6 atopic children. Intraclass correlation (ICC) and coefficient of variation (CV) were used for the reliability assessment. The relationships across esIgs were evaluated using network analysis; linear and logistic regressions were used to compare groups based on egg allergy status and comorbidities.

RESULTS

BBEA had high reliability (ICC >0.75) and low variability (CV <20%) and could detect known IgE-binding epitopes. Egg-allergic children had lower esIgA₁ (P = .010) and esIgG₁ (P = .016) and higher esIgE (P < .001) and esIgD (P = .015) levels compared to the atopic controls. Interestingly, within the allergic group, children with higher esIgD had decreased odds of anaphylactic reactions (OR =0.48, P = .038). Network analysis identified most associations between esIgE with either esIgG₄ or esIgD; indicating that IgE-secreting plasma cells could originate from either sequential isotype switch from antigen-experienced intermediate isotypes or directly from the IgD⁺ B cells.

CONCLUSIONS

Collectively, these data point toward a contribution of epitope-specific antibody repertoires to the pathogenesis of egg allergy.

Microbial Transglutaminase as a Tool to Improve the Features of Hydrocolloid-Based Bioplastics

Several proteins from animal and plant origin act as microbial transglutaminase substrate, a crosslinking enzyme capable of introducing isopeptide bonds into proteins between the aminoacids glutamines and lysines. This feature has been widely exploited to modify the biological properties of many proteins, such as emulsifying, gelling, viscosity, and foaming. Besides, microbial transglutaminase has been used to prepare bioplastics that, because made of renewable molecules, are able to replace the high polluting plastics of petrochemical origin. In fact, most of the time, it has been shown that the microbial enzyme strengthens the matrix of protein-based bioplastics, thus, influencing the technological characteristics of the derived materials. In this review, an overview of the ability of many proteins to behave as good substrates of the enzyme and their ability to give rise to bioplastics with improved properties is presented. Different applications of this enzyme confirm its important role as an additive to recover high value-added protein containing by-products with a double aim (i) to produce environmentally friendly materials and (ii) to find alternative uses of wastes as renewable, cheap, and non-polluting sources. Both principles are in line with the bio-economy paradigm.

IgE testing can predict food allergy status in patients with moderate to severe atopic dermatitis

BACKGROUND

Diagnosing food allergy in patients with atopic dermatitis (AD) is complicated by their high rate of asymptomatic sensitization to foods, which can lead to misdiagnosis and unnecessary food avoidance.

OBJECTIVE

We sought to determine whether food-specific (sIgE) or component immunoglobulin (Ig) E levels could predict allergic status in patients with moderate to severe AD and elevated total IgE.

METHODS

Seventy-eight children (median age, 10.7 years) with moderate to severe AD were assessed for a history of clinical reactivity to milk, egg, peanut, wheat, and soy. The IgE levels for each food and its components were determined by ImmunoCAP. The level and pattern of IgE reactivity to each food and its components, and their ratio to total IgE, were compared between subjects who were allergic and tolerant to each food.

RESULTS

Ninety-one percent of subjects were sensitized, and 51% reported allergic reactivity to at least 1 of the 5 most common food allergens. Allergy to milk, egg, and peanut were most common, and IgE levels to each of these foods were significantly higher in the allergic group. Component IgEs most associated with milk, egg, and peanut allergy were Bos d8, Gal d1, and Ara h2, respectively. The ratio of sIgE to total IgE offered no advantage to sIgE alone in predicting allergy.

CONCLUSION

Specific IgE levels and the pattern of IgE reactivity to food components can distinguish AD subjects allergic vs tolerant to the major food allergens and may therefore be helpful in guiding the clinical management of these patients.

Hyperresponsiveness to Boiled Egg Yolk in Early Life Leads to Prolonged Egg Allergy

Hen's egg is the most common allergen in IgE-mediated food allergy among children in Japan. Although the majority of patients with egg allergy can eat heated egg yolk safely because of its low allergenicity, severely allergic patients show an immediate-type reaction to heated egg yolk. We hypothesized that patients with hyperresponsiveness to boiled egg yolk may have difficulty in acquiring tolerance to egg. The purpose of this study was to examine the prognosis of patients with hyperresponsiveness to boiled egg yolk. Data from 121 patients with egg allergy who underwent oral food challenge (OFC) with boiled egg yolk between January 2012 and December 2013 were analyzed retrospectively. The proportion of patients who could consume heated whole egg 3 years after OFC was 15.4% in the OFC-positive group and 75.8% in the OFC-negative group. Hyperresponsiveness to boiled egg yolk in early life might lead to prolonged egg allergy in children. This finding might aid in the selection of an appropriate population requiring practical immunotherapy.

The Impact of Baked Egg and Baked Milk Diets on IgE- and Non-IgE-Mediated Allergy

Baked milk (BM) and baked egg (BE) diets are increasingly used in the management of milk and egg allergy, rather than avoidance. Children with tolerance versus reactivity to BM and BE may have smaller skin prick test and lower specific IgE, and BM-tolerant children have less basophil reactivity and more peripheral T regulatory cells. However, most milk- and egg-allergic children tolerate BM and BE and an individual's reactivity is unpredictable. Non-reactivity is due to conformational changes in the allergens. Significant differences in the published advice about methods of introduction exist from graded introduction at home to a medically supervised full dose. These approaches carry different risks and may have different immunological effects. Reactivity to BM is a predictor of a severe milk allergy. Therefore, medical supervision for BM and BE introduction is prudent. The baked diet allows dietary liberation. Most, but not all, BM- and BE-tolerant children continue eating the baked foods. The prognosis of children who can eat BM and BE is favorable with likely resolution of their allergy over the next few years. Murine models of BE diets demonstrate that heated egg can impart clinical protection against anaphylaxis and cause immune changes. Most observational human studies of BM and BE diets demonstrate clinical resolution of allergy and favorable immune changes versus regular care controls. However, the one randomized controlled trial for the BE diet in BE-tolerant children did not support an immune-modifying effect of the BE diet. Another study of BE immunotherapy is expected to be completed in 2018. There is currently no evidence for prevention of allergy with the baked diets. There may be a future role for BM and BE in liberating the diets of individuals with non-IgE-mediated allergy given recent studies that a subset of these patients can consume BM without a clinical reaction.

Assessment of the Allergenic Potential of the Main Egg White Proteins in BALB/c Mice

This work aimed to assess the contribution of the major egg white proteins, ovalbumin, ovomucoid, and lysozyme, to the induction and elicitation of allergenic responses. For this purpose, BALB/c mice were orally administered either the individual egg allergens or a mixture of the three proteins in the same proportion, to evaluate their relative allergenicity avoiding their different abundance in egg white. Cholera toxin was used as a T helper 2 (Th2)-polarizing adjuvant. Ovomucoid and lysozyme triggered the most severe anaphylaxis reactions upon oral challenge. In comparison to ovalbumin and ovomucoid, lysozyme was a more active promotor of early immunoglobulin E and immunoglobulin G1 production and stimulated stronger Th2-biased responses from both mesenteric lymph node and spleen cells. These results indicate that lysozyme is highly immunogenic and should be considered as a major allergen, whose clinical usefulness in the diagnosis, prognosis, and therapeutic approaches of egg allergy deserves further consideration.

Usefulness of molecular diagnosis in egg allergic children

INTRODUCTION

Egg allergy is one of the most common food allergies in children. Egg white, including ovomucoid (OVM or Gal d 1) and ovalbumin (OVA or Gal d 2), is the major source of allergens. The aim of this study was to assess the role of Gal d 1 and Gal d 2 in predicting the risk of anaphylaxis caused by eggs in children, and to compare this new diagnostic tool with established methods of allergen-specific IgE detection.

MATERIAL AND METHODS

One hundred and forty-eight children were divided into 2 groups according to a positive (group A, 33 children) or negative (group B, 115 children) history of anaphylaxis after ingestion/contact with eggs. All patients underwent an allergological evaluation by measurements of specific IgE against egg white: Gal d 1 and Gal d 2.

RESULTS

Higher levels of Gal d 1, Gal d 2 and IgE against egg white were detected in group A compared to group B (p < 0.001). Although the area under the curve was similar for Gal d 1 and Gal d 2, egg white specific IgE showed a better sensitivity (85%) for a cut-off value ≥ 0.975 kUA/l, while Gal d 1 and Gal d 2 demonstrated a better specificity (90% and 80%, respectively) for cut-off values ≥ 1.460 kUA/l and ≥ 2.310 kUA/l, respectively.

CONCLUSIONS

Egg white specific IgE showed a similar ability as Gal d 1 and Gal d 2 in differentiating children at risk for egg anaphylaxis, although Gal d 1 and Gal d 2 showed a better specificity.

Making the Most of In Vitro Tests to Diagnose Food Allergy

Various in vitro tests assess different aspects of the underlying immune mechanism of IgE-mediated food allergy. Some can be used for diagnostic purposes; specific IgE to allergen extracts is widely available; specific IgE to allergen components is used in most specialist centers, and the basophil activation test is becoming increasingly used clinically. IgE to allergen peptides, T-cell assays, allergen-specific/total IgE ratios, and allergen-specific IgG4/IgE ratios are currently reserved for research. Different factors can modulate the likelihood of IgE-mediated food allergy of a given allergy test result, namely, the patients' age, ethnicity, previous allergic reaction to the identified food, concomitant atopic conditions, and geographical location, and need to be taken into account when interpreting the allergy test results in the clinic. The importance of the specific food, the clinical resources available, and patient preferences are additional aspects that need to be considered when deciding whether an oral food challenge is required to reach an accurate diagnosis of IgE-mediated food allergy.

Food Allergy and Food Poisoning

Taken into account data from which is considered a product not safe, estimate the safe level of a contaminant on food, for example, always have many unavoidable uncertainties. It cannot be overemphasized enough, that this also happens as in any other human activity. In most cases, we hope, to define as clearly as possible the eventual risk associated with particular conditions of exposure to a given substance in food. There are numerous toxic compounds that reside naturally in certain foods that unable these to be consumed above certain limits or even are fully prohibited in some other countries. Chapter starts with a clear explanation of differences and relationships between food allergy and food poisoning, continued with main allergens in food and main toxics. Finally, authors summarize different origins of toxins and allergens (natural from foods, from additives, pollutants and food processing).

Food Allergy and Food Poisoning

Taken into account data from which is considered a product not safe, estimate the safe level of a contaminant on food, for example, always have many unavoidable uncertainties. It cannot be overemphasized enough, that this also happens as in any other human activity. In most cases, we hope, to define as clearly as possible the eventual risk associated with particular conditions of exposure to a given substance in food. There are numerous toxic compounds that reside naturally in certain foods that unable these to be consumed above certain limits or even are fully prohibited in some other countries. Chapter starts with a clear explanation of differences and relationships between food allergy and food poisoning, continued with main allergens in food and main toxics. Finally, authors summarize different origins of toxins and allergens (natural from foods, from additives, pollutants and food processing).

Relationship between specific IgE to egg components and natural history of egg allergy in Danish children

BACKGROUND

The majority of egg-allergic children develop tolerance over time. However, it may take numerous of consecutive egg challenges to get there as no good indices to predict tolerance exist.

OBJECTIVE

To investigate whether serial measurements of specific IgE to egg white, ovomucoid, ovalbumin, conalbumin, lysozyme, and egg yolk could improve the specificity of the diagnostic workup and aid in the decision when to rechallenge egg-allergic children.

METHODS

The outcome of oral food challenges with hen's egg and corresponding specific IgE levels were evaluated in children referred to The Allergy Center within an 8-year period. The egg-allergic children were rechallenged and had specific IgE levels measured once a year.

RESULTS

During a median follow-up of 26 months, 287 challenges and corresponding 287 serum analyses were performed in 130 children. Of the 130 children, 99 were egg allergic and 82 of these were rechallenged. Based on the initial diagnostic challenges only, area under the curve (AUC) estimates of the ability of specific IgE titers to distinguish between egg sensitization and egg allergy were only modest (maximum 0.83) and provided no clinical meaningful decision points. Specific IgE levels at baseline did not differ between tolerant and persistent allergic children. However longitudinally, acquisition of tolerance was associated with a decrease in IgE to egg white and to ovomucoid. In all cases of an increase in IgE to ovomucoid, the rechallenge was positive.

CONCLUSION

The decision when to rechallenge egg-allergic children should encounter the course of specific IgE.

Effect of malondialdehyde on the ovalbumin structure and its interactions with T84 epithelial cells

BACKGROUND

Protein oxidation can occur as a consequence of lipid peroxidation during food processing. The aim of this work was to explore the effect of malondialdehyde (MDA) modification of ovalbumin (OVA) on its interaction with T84 intestinal cells.

METHODS

Molecular dynamics simulation was employed for the prediction of MDA modification in the OVA, while introduced structural changes were evaluated by measurement of carbonyl group content, fluorescence spectra, MS/MS analysis, and IgE reactivity. Effects of MDA modified OVA on T84 epithelial cells were analyzed by gene expression for pro-inflammatory cytokines and protein secretion.

RESULTS

Out of 9 predicted, five modified Lys residues were confirmed by MS/MS analysis: ⁵¹TQINKVVR⁵⁸, ⁸⁵DILNQITKPNDVYSFSLASR¹⁰⁴, ¹¹¹YPILPEYLQCVKELYR¹²⁶, ¹⁸⁷AFKDEDTQAMPFR¹⁹⁹, ²⁷⁷KIKVYLPR²⁸⁴, and ²⁷⁸IKVYLPR²⁸⁴. The introduced MDA modifications influenced profile of IgE reactivity to OVA. Treatment of T84 epithelial cells with OVA and OVA modified with 1mM MDA, induced up-regulation of pro-inflammatory cytokines (IL-1β, IL-25, IL-33, TSLP and TNFα), while OVA modification with 10mM MDA induced down regulation of the cytokine expression profile, except for IL-1β. OVA and OVA modified with 1mM MDA induced secretion of epithelial cells specific cytokine IL-33.

CONCLUSIONS

This finding indicated that OVA and its MDA modified form have the potential to trigger the innate immunity by inducing up-regulation and secretion of pro-allergenic IL-33 in T84 intestinal epithelial cells.

GENERAL SIGNIFICANCE

Interactions of ovalbumin and its MDA modified form with intestinal epithelial cells can induce a specific immunological priming necessary for the downstream activation of innate immunity.

Component-resolved analysis of IgA, IgE, and IgG4 during egg OIT identifies markers associated with sustained unresponsiveness

BACKGROUND

In a previously reported CoFAR study, 55 subjects with egg allergy underwent randomized, placebo-controlled egg oral immunotherapy (eOIT). Active treatment induced desensitization in most and sustained unresponsiveness (SU) in a smaller subset. We hypothesized that component-resolved analysis of IgE, IgG4, IgA, IgA1, and IgA2 may identify potential biomarkers of SU in OIT subjects.

METHODS

Longitudinal samples for 51 egg-allergic subjects (37 active and 14 placebo) were available. Egg white (EW)-, ovalbumin (OVA)-, and ovomucoid (OVM)-specific levels of IgA, IgA1, and IgA2 were quantified by ELISA. IgE and IgG4 to these antigens were quantified using ImmunoCAP^® . Clinical responders achieved SU to egg; all others were considered nonresponders. Between-group comparisons were made among active and placebo, as well as responders and nonresponders.

RESULTS

No placebo subjects achieved responder status. Through month 48, among the 37 active subjects, baseline IgE-OVM was lower in responders (median 3.97 kU/l, n = 19) than in nonresponders (10.9 kU/l, n = 18, P = 0.010). Logistic regression analysis revealed that lower baseline IgE-EW (P = 0.038), IgE-OVM (P = 0.032), and a higher IgG4/IgE-OVM ratio (P = 0.013) were associated with clinical response. Relative increases in IgG4-EW, IgA-EW, and IgA2-EW were observed in responders (P = 0.024, 0.024, and 0.029, respectively). IgG4/IgE, IgA/IgE, and IgA2/IgE ratios for EW and IgA/IgE ratio for OVA were found to be significantly elevated among responders (P = 0.004, 0.009, 0.028, and 0.008, respectively).

CONCLUSIONS

Increased IgG4-EW, IgA-EW, and IgA2-EW during eOIT are associated with clinical response to eOIT. Lower pretreatment IgE-EW and IgE-OVM are also associated with SU. Future studies are needed to evaluate and validate these potential biomarkers.

Heated egg yolk challenge predicts the natural course of hen's egg allergy: a retrospective study

BACKGROUND

Children do not always outgrow hen's egg allergies in early childhood. Because egg yolks are less allergenic than egg whites, we performed an oral food challenge with heated egg yolk slightly contaminated with egg white (EYSEW OFC) in infants allergic to hen's egg. We hypothesized that the EYSEW OFC results would predict the egg allergy's natural course.

METHODS

We retrospectively reviewed participants with hen's egg allergy who underwent their first EYSEW OFC at 12-23 months of age between 2004 and 2010. Participants who passed the first EYSEW OFC were defined as EYSEW-tolerant, and participants who failed the OFC were defined as EYSEW-reactive. Participants who passed the EYSEW OFC underwent an OFC with half of a heated whole egg (WE OFC). Participants who passed a WE OFC were defined to be heated hen's egg-tolerant. Participants who failed the EYSEW OFC or the WE OFC underwent another OFC at least 6 months later. We compared tolerance to heated hen's egg at 36 months after the first EYSEW OFC between EYSEW-tolerant and EYSEW-reactive participants. Univariate and multivariate logistic regression analyses were conducted.

RESULTS

Of the 197 included participants (median age: 18.3 months; range: 12.1-23.8 months), 179 (90.9 %) were EYSEW tolerant and 18 (9.1 %) were EYSEW reactive. At 36 months after the first EYSEW OFC, 164 EYSEW-tolerant (91.6 %) and 12 EYSEW-reactive participants (66.7 %) achieved heated hen's egg tolerance. In the univariate logistic regression analyses, EYSEW-reactive participants (crude odds ratio [OR], 5.5 [95 % confidence intervals [CI], 1.8-16.6]; p = 0.003) and those with baseline egg white sIgE levels (crude OR: 3.9 per ten-fold increase [95 % CI, 1.5-10.2]; p = 0.005) had greater odds of persistent allergy to hen's egg at 36 months after the first EYSEW OFC. In a multivariate logistic regression analysis after adjustment for baseline egg white sIgE, EYSEW-reactive participants had greater odds of persistent allergy to hen's egg than EYSEW-tolerant participants (adjusted OR: 4.6 [95 % CI, 1.5-15.0]; p = 0.003).

CONCLUSIONS

Classifying infants who are allergic to hen's egg into EYSEW tolerant and EYSEW reactive groups was useful in determining prognosis.

Baked Milk and Egg Diets for Milk and Egg Allergy Management

In baked form, cow's milk and egg are less allergenic and are tolerated by most milk- and egg-allergic children. Not only may including baked milk and egg in the diets of children who are tolerant improve nutrition and promote more social inclusion but there is also evidence that inclusion may accelerate the resolution of unheated milk and egg allergy. Further research is needed on biomarkers that can predict baked milk or egg reactivity; however, data suggest casein- and ovomucoid-specific immunoglobulin E levels may be useful. Physician-supervised introduction of baked milk and egg is recommended because anaphylaxis has occurred.

Baked Egg and Milk Exposure as Immunotherapy in Food Allergy

Baked milk and egg have the potential to act as a form of oral immunotherapy (OIT). Clinical studies have shown that a majority of milk- and egg-allergic children can tolerate these allergens modified in baked form, and immunologic changes reported in subjects ingesting baked milk and egg mirror those seen in food allergy OIT trials. In addition, several studies have indicated that resolution of milk and egg allergies occur sooner in populations regularly ingesting baked milk and egg. Oral food challenges remain the best method for determining tolerability of baked milk and egg since baseline characteristics and diagnostic testing have not been reliable predictors. In this review, we explore the tolerability of baked milk and egg and their potential as OIT treatment for milk and egg allergy.

Current challenges facing the assessment of the allergenic capacity of food allergens in animal models

Food allergy is a major health problem of increasing concern. The insufficiency of protein sources for human nutrition in a world with a growing population is also a significant problem. The introduction of new protein sources into the diet, such as newly developed innovative foods or foods produced using new technologies and production processes, insects, algae, duckweed, or agricultural products from third countries, creates the opportunity for development of new food allergies, and this in turn has driven the need to develop test methods capable of characterizing the allergenic potential of novel food proteins. There is no doubt that robust and reliable animal models for the identification and characterization of food allergens would be valuable tools for safety assessment. However, although various animal models have been proposed for this purpose, to date, none have been formally validated as predictive and none are currently suitable to test the allergenic potential of new foods. Here, the design of various animal models are reviewed, including among others considerations of species and strain, diet, route of administration, dose and formulation of the test protein, relevant controls and endpoints measured.

Egg proteins as allergens and the effects of the food matrix and processing

Hen eggs are an important and inexpensive source of high-quality proteins in the human diet. Egg, either as a whole or its constituents (egg yolk and white), is a key ingredient in many food products by virtue of its nutritional value and unique functional properties, such as emulsifying, foaming, and gelling. Nevertheless, egg is also known because of its allergenic potential and, in fact, it is the second most frequent source of allergic reactions, particularly in children. This review deals with the structural or functional properties of egg proteins that make them strong allergens. Their ability to sensitize and/or elicit allergic reactions is linked to their resistance to gastroduodenal digestion, which ultimately allows them to interact with the intestinal mucosa where absorption occurs. The factors that affect protein digestibility, whether increasing it, decreasing it, or inducing a different proteolysis pattern, and their influence on their capacity to induce or trigger an allergic reaction are discussed. Special attention is paid to the effect of the food matrix and the processing practices on the capacity of egg proteins to modulate the immune response.

Egg Allergy in Adolescent and Adult Patient Suffering from Atopic Dermatitis – Association with Concomitant Allergic Diseases

Background: A few reports demonstrate the occurrence of egg allergy in adolescent and adult patients suffering from atopic dermatitis and the association of this allergy to other food and aeroallergens. Aims and Objectives: The aim of this study is to evaluate the occurrence of egg allergy in patients suffering from atopic dermatitis at the age 14 years and older and to evaluate the relationship between egg allergy or egg sensitisation and the sensitisation to dust, mites, feather, and animal dander. Materials and Methods: Complete dermatological and allergological examination was performed. These parameters were examined: food allergy and food sensitisation to egg white and yolk, to mites, animal dander (mixture), feather and dust. The statistical evaluation of the relations among egg allergy, egg sensitisation and sensitisation to mites, animal dander (mixture), feather and dust was performed. Two hundred and eighty eight patients were included in the study (90 men, 198 women, with the average age 25.2). Results and Conclusion: Egg allergy was recorded in 5% and egg sensitisation in 20% of patients; sensitisation to dust is recorded more often in patients with positive results in sIgE for egg white and/or yolk.

Attenuated Allergenic Activity of Ovomucoid After Electrolysis

Ovomucoid (OMC) is the most prominent allergen causing hen's egg allergy, containing disulfide (S-S) bonds that may be responsible for its allergic action. As S-S bonds may be reduced during electrolysis, this study was undertaken to evaluate modulation of the allergic action of OMC after electrolysis. Electrolysis was carried out for 1% OMC containing 1% sodium chloride for 30 minutes with a voltage difference of 90 V, 0.23 A (30 mA/cm²). Protein assays, amino acid measurement, and mass spectrometry in untreated OMC and OMC on both the anode and cathode sides after electrolysis were performed. Moreover, 21 patients with IgE-mediated hen's egg allergy were evaluated by using the skin prick test (SPT) for untreated OMC and OMC after electrolysis. The allergic action of OMC was reduced after electrolysis on both the anode and cathode sides when evaluated by the SPT. The modifications of OMC on electrolysis caused the loss of 2 distinct peptide fragments (57E-63K and 123H-128R) as seen on matrix-associated laser desorption/ionization time-of-flight mass spectrometry. The total free SH groups in OMC were increased on the cathode side. Although the regions of S-S broken bonds were not determined in this study, the change in S-S bonds in OMC on both the anode and cathode sides may reduce the allergenic activity.

Effects of Egg White Consumption on Immune Modulation in a Mouse Model of Trimellitic Anhydride-induced Allergy

Egg allergy has been shown to be the most common food allergy in children with atopic dermatitis. Allergic reactions to proteins derived from egg white (EW) are more common than those derived from egg yolk. Ovomucoid, ovalbumin, ovotransferrin, and lysozyme have been identified as major allergens in EW. This study was conducted to evaluate the effect of EW on immune modulation in an induced allergy mouse model. A total of 50 five-week-old BALB/c male mice were treated with trimellitic anhydride (TMA) for three weeks to induce allergy-like symptoms. The TMA-treated mice were rested for one week and then divided into five groups and fed 0, 10, 50, and 100 mg/d EW for four weeks. All EW consumption groups showed no significant increase or decrease in the populations of white blood cells; however, a significant increase in B-lymphocyte activity was observed in the fourth week. Furthermore, EW consumption did not influence serum immunoglobulin G and immunoglobulin E levels. Taken together, these data demonstrate that the consumption of EW by TMA-treated mice did not increase allergic parameters such as serum IgE level, but enhanced the lymphocyte activities against pathogens. Therefore, this study suggests that the consumption of EW promotes Th2 immune modulation, and EW could be an excellent candidate for maintaining health.

Native and denatured egg white protein IgE tests discriminate hen's egg allergic from egg-tolerant children

BACKGROUND

Accurate diagnosis of egg allergy by IgE testing is challenged by a large number of atopic subjects sensitized, but clinically tolerant to eggs. In addition, discrimination between allergy to raw only, or raw and cooked egg allergy is important. In this study, we investigate the diagnostic performance of IgE tests to native and denatured egg proteins.

METHODS

According to food challenges and clinical tolerance, study subjects were randomized to the following groups: (Group A) sensitized but clinically tolerant to egg, (Group B) allergic to raw egg only, or (Group C) allergic to raw and cooked egg. Serum-specific IgE to native or reduced and oxidized egg white, ovomucoid, and ovalbumin were measured.

RESULTS

Increasing titers of specific IgE to the various proteins were found according to the degree of the egg allergy. Cut-off values for IgE testing to native egg could be determined to distinguish between raw egg allergic and egg-tolerant subjects (1.6 kU/l), as well as raw and cooked egg allergic and egg-tolerant subjects (4.1 kU/l). ROC curves analysis showed that native ovalbumin was the best test for the diagnosis of allergy to raw and cooked egg, and native ovomucoid was best to distinguish between allergy to raw only, and allergy to raw and cooked egg. Sequential testing improved the diagnosis, when in addition to IgE to native egg white, IgE to native ovalbumin was tested for the diagnosis of raw and cooked egg allergy, and IgE to native ovomucoid for the discrimination between allergy to raw only, or to raw and cooked eggs.

CONCLUSION

The diagnosis of egg allergy can be significantly improved using a panel of IgE tests to egg proteins in the native or denatured form. The accuracy can be improved using combined IgE testing.

A modified weight-of-evidence approach to evaluate the allergenic potential of food proteins

Schematic interpretation of a modified weight-of-evidence approach for evaluating the allergenic potential of food proteins.

Determination of the clinical egg allergy phenotypes using component-resolved diagnostics

IgE-mediated egg allergy presents as one of the most common food allergies in children and is a food which is widely consumed all over the world. Measurement of egg white-specific IgE levels has been shown to be a poor predictor of clinical phenotypes of egg allergy, including to raw egg white, but particularly to baked or cooked egg. Egg white and yolk contain more than 20 different glycoproteins, including ovomucoid, ovalbumin, ovotransferrin, alpha-livetin, and the newly identified Gal d 6. Recent developments in component-resolved diagnostic technology, including microarrays, have enabled us to improve the way in which we diagnose food allergy. This technology allows us to measure specific IgE antibodies to individual egg allergens which have been highly purified. Characterization of the major egg allergens could help profile the relevant binding epitopes to each region and may also help diagnose the different clinical phenotypes of egg allergy.

Effects of Egg White Consumption on Allergy, Immune Modulation, and Blood Cholesterol Levels in BALB/c Mice

We previously demonstrated that water-soluble egg yolk extract is not related to elevation of serum immunoglobulin E, which can initiate allergic reactions; however, it increases the level of high density lipoprotein (HDL)-cholesterol and the activity of B lymphocytes. In this study, egg white (EW) was fed to BALB/c mice to determine its influence on growth efficiency, immune modulation, and changes in serum lipid levels. A total of 50 five-wk-old BALB/c male mice were divided into 5 groups, 4 of which were fed 0, 10, 50, or 100 mg/d EW for 4 wk. Mice with an uptake of 10, 50 and 100 mg/d EW showed no significant changes in daily weight gain, feed efficiency rate, or populations of white blood cells. However, the activities of both B and T lymphocytes were significantly increased in all three EW groups at the final week of treatment. Interestingly, serum levels immunoglobulin E were not altered by EW consumption, but the IgG level was significantly increased in the 100 mg/d EW group. Serum lipid profile analyses showed no significant changes in total cholesterol, HDL, low density lipoprotein, or triglyceride levels by EW consumption. Taken together, these data demonstrate that consumption of EW promotes immune cell activities and the upregulation of serum IgG levels. However, we found no changes in serum lipid profiles and IgE levels. Therefore, our study suggests that consumption of EW might not be related to the risk of food allergy, but could be an excellent candidate for the maintenance of physiological homeostasis.

Laboratorial characteristics of patients with diarrhoea suffering from egg white allergy

BACKGROUND

Egg allergy is associated with diarrhoeal symptoms. However, the mechanism underlying allergic diarrhoea remains unclear.

OBJECTIVE

To determine whether egg white-specific IgE antibodies coexist with egg white-specific IgG antibodies in patients with egg allergy featuring diarrhoeal symptoms, and whether there is any relationship between these two antibody types.

METHODS

A total of 89 patients with egg allergy featuring diarrhoeal symptoms (average age, 23.2 years; range, 1-78 years), all of whom tested positive for egg white-specific IgG, were enrolled in this study. The concentration of total IgE, egg white-specific IgE and number of eosinophils in the serum were determined.

RESULTS

Among the 89 egg white allergic patients tested, 49 (55.1%) patients showed high reactivity to egg white-specific IgG, 48 (53.9%) patients had elevated serum total IgE levels, and 25 (28.1%) patients had elevated absolute eosinophil numbers. Out of the 89 egg white allergic patients, 25 showed elevated egg white-specific IgE antibody levels. Of the 25 patients who were positive for egg white-specific IgE antibody, 21 presented high sensitive reaction to egg white-specific IgG, three presented moderate sensitive reaction to egg white-specific IgG, and one presented mild sensitive reaction to egg white-specific IgG. A moderate correlation between egg white-specific IgG and egg white-specific IgE, egg white-specific IgG and absolute eosinophil number was found in the egg white allergic patients (r=0.438, P=0.000; r=0.322, P=0.002). Egg white-specific IgE levels varied in different age groups; the egg white-specific IgE concentration of younger patients (age≤18 years, mean rank 54.29) was significantly higher than that of the adult patients (age>18 years, mean rank 34.61) (Z=-3.629, P=0.000).

CONCLUSION

Egg white-specific IgE antibody could coexist with egg white-specific IgG antibody in patients suffering from egg white allergy. Aberrant changes in the concentration of egg white-specific IgE antibody were associated with the presence of egg white-specific IgG antibody.

Peptide based immunotherapy: a pivotal tool for allergy treatment

Immunotherapies with T-cell epitope peptides have shown a promising impact over allergic diseases as a potential therapeutic tool in in vitro and in vivo conditions. It is recognized as an effective treatment with long lasting clinical effects and subsequent reduction of the allergic inflammatory reactions. In this review, we have summarized the role of peptide based immunotherapy and emphasis has been given to the recent advancement in pollen, cat, hymenoptera venom, and food allergy.