Molecular interaction of sulfonamides and ovalbumin, an allergenic egg protein, exploring biophysical, theoretical and biological studies

Biophysical, theoretical and biological in vitro studies were carried out to evaluate the interaction of the main allergen protein of egg white (ovalbumin, OVA) with sulphonamides (SA): sulphathiazole (S1), sulfaquinoxaline (S2), sulfadimethoxine (S3) and sulfamethazine (S4). The binding constants for the OVA-SA supramolecular complexes ranged from 1.20 to 30.66 × 10⁵ M^-1, observing the following order of affinity: S1 > S2 > S4 > S3. The preferential forces in the stabilization of the OVA complexes with S2 and S3 were hydrogen bonds and Van der Waals forces, whereas for OVA-S1 and OVAS4, were electrostatic interactions. Interaction process led to a change in the native structure of the protein, which may potentiate its natural allergenicity. Cations Ca(II), Mg(II) and Fe(III) favor the interaction of OVA with S1 and S2. The theoretical studies performed were consistent with the spectroscopic data. Finally, it was found that the interaction process for sulfonamides evaluated with OVA change the inhibition activity profile these antibiotics against strains of Escherichia coli ATCC 25922 and Bacillus megaterium APFSG3isox, but not the minimal inhibitory concentration values.

Adjuvant-free immunization with infective filarial larvae as lymphatic homing antigen carriers

Controlled infection with intestinal nematodes has therapeutic potential for preventing the symptoms of allergic and autoimmune diseases. Here, we engineered larvae of the filarial nematode Litomosoides sigmodontis as a vaccine strategy to induce adaptive immunity against a foreign, crosslinked protein, chicken egg ovalbumin (OVA), in the absence of an external adjuvant. The acylation of filarial proteins with fluorescent probes or biotin was not immediately detrimental to larval movement and survival, which died 3 to 5 days later. At least some of the labeled and skin-inoculated filariae migrated through lymphatic vessels to draining lymph nodes. The immunization potential of OVA-biotin-filariae was compared to that of an OVA-bound nanoparticulate carrier co-delivered with a CpG adjuvant in a typical vaccination scheme. Production of IFNγ and TNFα by restimulated CD4+ cells but not CD8+ confirmed the specific ability of filariae to stimulate CD4+ T cells. This alternative method of immunization exploits the intrinsic adjuvancy of the attenuated nematode carrier and has the potential to shift the vaccination immune response towards cellular immunity.

Comparison of Glycated Ovalbumin-Monosaccharides in the Attenuation of Ovalbumin-Induced Allergic Response in a BALB/C Mouse Model

The aim of the present study was to compare various glycated ovalbumin (OVA)-monosaccharides, including OVA-mannose (Man), -glucose, -ribose, and -fructose, in the attenuation of OVA-induced allergic response in a BALB/C mouse model and the potential mechanisms of immunological modulation. The glycated OVA forms were prepared by Maillard reactions. OVA-Man significantly reduced the frequency of allergic signs. Mouse mast cell protease enzyme concentration was significantly reduced in the OVA-Man group (549.80 ± 84.67 ng/mL, p < 0.05). The OVA-Man group also had a lower histamine concentration (30.96 ± 1.12 ng/mL) as compared with the positive control OVA group (44.43 ± 0.71 ng/mL, p < 0.05). Both specific IgG and IgE were significantly reduced in the OVA-Man-treated group (p < 0.05). The OVA-Man group exhibited decreased concentrations of IL-4 (67.98 ± 3.11 pg/mL) and IL-17 (67.98 ± 3.11 pg/mL) and an increased concentration of IL-12 (336.70 ± 18.69 pg/mL, p < 0.05) compared with the positive control. Mannosylation played a vital role in allergen recognition, implicating deleterious downstream Th2 cell activation, cytokine secretion, and IgE production. This result indicates that different glycans target specific DC receptors, and differential DC processing, antigen presentation, and T cell response leads to altered variation in allergic response. OVA-Man exhibited minimal DC internalization, DC processing, MHC antigen presentation, and antigen-specific T cell activation, resulting in an attenuated allergic response and validating its efficacy as a potential immunotherapeutic candidate to treat egg allergy.

Effect of Covalent Interaction with Chlorogenic Acid on the Allergenic Capacity of Ovalbumin

Ovalbumin (OVA) is a major allergen in avian egg white. Here, we investigated the conjugation of OVA and chlorogenic acid (CHA) to reduce the allergenic capacity of OVA. OVA-CHA conjugate was characterized by SDS-PAGE, MALDI-TOF-MS, differential scanning calorimetry, and multispectroscopic methods. Sites of the OVA-CHA conjugate were identified by LC-MS/MS. CHA possibly conjugated with Lys20 and Lys17 in OVA, which resulted in the unfolding of OVA. ELISA and Western blot assay indicated that the OVA-CHA conjugate reduced the IgE binding capacity of OVA. The results also indicated that the ability of the OVA-CHA conjugate to activate histamine release was reduced. The decreased allergenic capacity of OVA was attributed to changes in the protein structure. Moreover, the CHA binding site in OVA might directly shield the linear IgE epitope, thereby reducing the IgE binding ability. Also, the OVA-CHA conjugate showed high antioxidant activity. OVA conjugated with CHA may be a promising method of OVA hyposensitization.

Early-life gut microbiome and egg allergy

BACKGROUND

Gut microbiota may play a role in egg allergy. We sought to examine the association between early-life gut microbiota and egg allergy.

METHODS

We studied 141 children with egg allergy and controls from the multicenter Consortium of Food Allergy Research study. At enrollment (age 3 to 16 months), fecal samples were collected, and clinical evaluation, egg-specific IgE measurement, and egg skin prick test were performed. Gut microbiome was profiled by 16S rRNA sequencing. Analyses for the primary outcome of egg allergy at enrollment, and the secondary outcomes of egg sensitization at enrollment and resolution of egg allergy by age 8 years, were performed using Quantitative Insights into Microbial Ecology, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States, and Statistical Analysis of Metagenomic Profiles.

RESULTS

Compared to controls, increased alpha diversity and distinct taxa (PERMANOVA P = 5.0 × 10-4 ) characterized the early-life gut microbiome of children with egg allergy. Genera from the Lachnospiraceae, Streptococcaceae, and Leuconostocaceae families were differentially abundant in children with egg allergy. Predicted metagenome functional analyses showed differential purine metabolism by the gut microbiota of egg-allergic subjects (Kruskal-Wallis Padj  = 0.021). Greater gut microbiome diversity and genera from Lachnospiraceae and Ruminococcaceae were associated with egg sensitization (PERMANOVA P = 5.0 × 10-4 ). Among those with egg allergy, there was no association between early-life gut microbiota and egg allergy resolution by age 8 years.

CONCLUSION

The distinct early-life gut microbiota in egg-allergic and egg-sensitized children identified by our study may point to targets for preventive or therapeutic intervention.

A very unusual case of food allergy, between FPIES and IgE-mediated food allergy

Food protein induced enterocolitis syndrome (FPIES) is a food-related gastrointestinal hypersensitivity disorder, probably non-IgE-mediated. Over the years, various diagnostic criteria have been proposed to identify FPIES. In the last few years, there was an increased interest from researchers about FPIES's syndrome, that frequently brought to discover new aspects of this disease. We describe an unusual case of FPIES to egg in a 21-months-old child, because of its clinical characteristics that reflect some aspects of IgE-mediated allergy and other of non IgE-mediated allergy. Although we believe that the most correct diagnosis for our case is FPIES, we think also that this is undoubtedly an atypical form. This is in fact, the first description of a patient who simultaneously has both clinical expressions of IgE-mediated FA that of FPIES. Our case highlights the need to review criteria for FPIES diagnosis.

[Prevalence of self-reported allergy, food hypersensitivity and food intolerance and their influencing factors in 0-36 months old infants in 8 cities in China]

OBJECTIVE

To measure the prevalence, the possible causes and the influencing factors of allergy, food hypersensitivity and food intolerance in 0-36 month old infants in 8 cities in China.

METHOD

Totally 2632 infants from the outpatient departments of prevention and health care of two representative hospitals in 8 Chinese cities were randomly selected by applying multistage cluster sampling method from October 2011 to March 2012, and a one-on-one survey to infants' parents was conducted to investigate infants' sensitization status.

RESULT

Self-reported infant allergy rate was 17.97% (473/2632) ; self-reported food hypersensitivity and food intolerance rates were 6.53% (172/2632) and 4.26% (112/2632) , respectively. The proportion of self-reported food hypersensitivity of 0-12 months old infants was 4.47% (74/1656) and their top five allergens in a descending order were eggs (28.38%) , shrimp (25.68%) , fish (21.62%) , milk (18.92%) and wheat (4.05%) . The proportion of self-reported 13-36 months old infant's food hypersensitivity was 10.05% (98/976) . The top five allergens were shrimp (33.93%) , fish (26.79%) , eggs (23.21%) , milk (12.50%) and soy (3.57%) in 13-24 months group, while fish (38.24%) , shrimp (35.29%) , eggs (20.59%) , milk (20.59%) and peanuts (2.94%) in 25-36 months group. Both 7-12 and 13-24 month old were the highest incidence (both of them were 11.98%, 58/484) of age for developing food hypersensitivity and 7-12-month old was also the highest incidence (8.47%, 41/484) of age for food intolerance. The self-reported food intolerance rate was 3.68% (61/1656) and 5.23% (51/976) in the two age groups, respectively. Age, parental history of allergy and father's educational level (OR was 2.452, 1.482 and 2.598, respectively, P < 0.01) were the risk factors of food hypersensitivity; within two weeks of sickness (OR = 1.267, P < 0.05) was the risk factor of food intolerance.

CONCLUSION

Infancy was the most vulnerable period of life of getting allergy, therefore, it is necessary for all infants to prevent allergy through a variety of effective strategies.

Influenza: Update for the 2013-2014 season

New vaccine products are available for this season, including a recombinant agent that has no egg protein.

Proteomic analysis of ovomucoid hypersensitivity in mice by two-dimensional difference gel electrophoresis (2D-DIGE)

There is a need to develop reliable methods to assess the safety of genetically modified and other novel foods. The aim of this study was to identify protein biomarkers of food allergy in mice exposed to ovomucoid (OVM), a major food allergen found in chicken egg white. BALB/c mice were repeatedly sensitized by gavage with OVM and cholera toxin (CT) and control mice were exposed to a mixture of amino acids with CT. At the endpoint, all mice were challenged intraperitoneally with OVM and alum. Type-1 hypersensitivity was confirmed in OVM-sensitized mice by observation of clinical signs of anaphylaxis and elevated levels of plasma histamine, OVM-specific IgE and OVM-specific IgG by ELISA. Differential protein expression was assessed in albumin-depleted plasma as well as in mesenteric lymph node, liver, spleen, and ileum by two-dimensional difference gel electrophoresis (2D-DIGE). Differentially expressed proteins were identified by liquid chromatography with tandem mass spectrometry. Plasma proteins overexpressed in OVM-sensitized mice included haptoglobin (41-fold), serum amyloid A (19-fold) and peroxiredoxin-2 (1.9-fold). Further validation of these plasma proteins in other animal models of food allergy with different food allergens is required to assess their potential as candidate biomarkers for use in evaluating the allergenicity of novel foods.

Vaccination and anaphylaxis

The incidence of anaphylactic or severe allergic reactions to vaccines is very low, less than one case per million vaccine doses. Larger studies from later years report no deaths. The cause of the reaction is usually not the immunizing antigen itself, but rather some other vaccine ingredient such as egg protein from the production process or gelatin added as a stabilizer. Most people with egg allergy can be vaccinated without any reaction. Vasovagal reactions with or without hyperventilation are common after vaccination. They can be rather dramatic and are often mistaken for anaphylactic reactions. Correct diagnosis is important in making it possible to vaccinate those who might otherwise run the risk of serious infections.

Peptic digestibility of raw and heat-coagulated hen's egg white proteins at acidic pH range

Allergenicity in food proteins is generally dependent on their heat stability and resistance to digestive enzymes together with the presence of IgE-recognizing epitopes on the molecules. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting, we assessed peptic digestibility of raw and heat-coagulated hen's egg white proteins at acidic pH range (1.5-4.0). Ovalbumin in raw egg white was slightly digested by pepsin at pH 1.5 and pH 2.0, and was almost resistant to the enzyme at pH 2.5 and over, which was altered in heat-coagulated egg white at the pH range from 1.5 to 2.5 where the protein was well digestive against the enzyme. Peptic digestibility of ovomucoid in raw egg white was good at the pH range from 1.5 to 2.5, but almost non-existent at pH 3.0 and over where the improvement of the digestibility of the protein was not found even in heat-coagulated egg white. As the stomach in new born infants shows a low amount of secretary pepsin and an out of optimum pH of peptic activity, low digestibility of ovalbumin and ovomucoid in raw and heat-coagulated egg white at over pH 3.0 is supposed to be responsible for their allergenicity and delayed outgrowth from hen's egg allergy in patients with delayed maturation of stomach functions.

Patch testing with egg represents a useful integration to diagnosis of egg allergy in children with atopic dermatitis

Our aim was to investigate atopy patch and skin prick test reactions to egg in 85 children with atopic dermatitis, and to evaluate their relevance by performing repeated open challenges with egg. Thirty-one percent of our patients showed an eczematous response to the challenge. Positive reactions to atopy patch and skin prick tests were recorded in 37% and 19%, respectively. Atopy patch test sensitivity proved significantly higher than that of skin prick test (79.6% vs. 46.2%), whereas specificity was lower (81.4% vs. 93.2%). Our data suggest that combined skin prick and patch testing improves screening for egg allergy in affected children, identifying 92% of those who were challenge positive among our patients.

Immunization of egg-allergic individuals with egg- or chicken-derived vaccines

Viruses used in several vaccines are propagated in embryonated eggs. These vaccines contain variable quantities of residual egg or chicken proteins and pose risks when administered to egg- or chicken-sensitive persons. This article highlights differences in how vaccines are prepared, with emphasis on the quantitation of residual egg-derived protein in each vaccine. Published reports on the frequency and severity of these vaccine-induced allergic reactions are reviewed, and an algorithm is provided for the preimmunization evaluation of egg-sensitive persons.

Thresholds of clinical reactivity to milk, egg, peanut and sesame in immunoglobulin E-dependent allergies: evaluation by double-blind or single-blind placebo-controlled oral challenges

BACKGROUND

The prevalence of food anaphylaxis due to masked allergens has increased within the last 10 years. Contamination of manufactured products by food allergens is a key concern for food industries.

OBJECTIVE

To determine quantities eliciting reactions in patients who have an IgE-dependent food allergy, thanks to standardized oral provocation tests. To evaluate the subsequent levels of sensitivity required for the detection tests of allergens for egg, peanut, milk and sesame.

METHODS

Prick-in-prick tests, Cap system RAST, and single or double-blind placebo-controlled food challenges (SBPCFC or DBPCFC) were performed. The doses of natural food were gradually increased from 5 to 5000 mg for solid food and from 1 to 30 mL for peanut oil, sunflower oil, soy oil and sesame oil.

RESULTS

Data from 125 positive oral challenges to egg, 103 to peanut, 59 to milk and 12 to sesame seeds were analysed. Haemodynamic modifications were observed in 2%, 3%, 1.7%, and 8% of the oral challenges (OCs) to egg, peanut, milk and sesame, respectively. Respiratory symptoms were observed in 12%, 20%, 10% and 42% of egg, peanut milk and sesame allergies, respectively. A cumulative reactive dose inferior or equal to 65 mg of solid food or 0.8 mL of milk characterized 16%, 18%, 5% and 8% of egg, peanut, milk and sesame allergies, respectively. 0.8% of egg allergies, 3.9% of peanut allergies, and 1.7% of milk allergies reacted to 10 mg or less of solid food or to 0.1 mL for milk. The lowest reactive threshold has been observed at less than 2 mg of egg; 5 mg of peanut, 0.1 mL of milk and 30 mg of sesame seed. Ten out of 29 OC with peanut oil, two out of two OC with soy oil and three out of six OC with sunflower oil were positive. Five out six OC with sesame oil were positive: 1 and 5 mL induced an anaphylactic shock.

CONCLUSION

The risk of asthma and anaphylactic shock to sesame and peanut is confirmed. Minimal reactive quantities show that, in order to guarantee a 95% safety for patients who are allergic to egg, peanut and milk, and on the basis of consumption of 100 g of food, the detection tests should ensure a sensitivity of 10 p.p.m. for egg, 24 p.p.m. for peanut and 30 p.p.m. for milk proteins. Oil allergies being considered, the limit of sensitivity should fall to 5 p.p.m.

Egg white proteins as inhalant allergens associated with baker's asthma

BACKGROUND

Bakery workers may develop IgE-mediated allergy to liquid and aerosolized hen's egg proteins that are commonly used in the baking and confectionery industries.

METHODS

We studied four bakery workers who had work-related allergic respiratory symptoms upon exposure to egg aerosols. The causative role of egg proteins in their respiratory symptoms was investigated by immunologic and specific inhalation challenge (SIC) tests.

RESULTS

Skin prick tests to egg white extract and to lysozyme gave positives responses in all the subjects, to ovalbumin in two, to ovomucoid in one and to egg yolk in two subjects. They were also sensitized to wheat, rye and barley flours. Specific IgE determinations to egg white were positive in all patients, to lysozyme in two, to ovalbumin in three, to ovomucoid in two and to egg yolk in two of them. Methacholine inhalation tests revealed bronchial hyperresponsiveness in all workers (PC20 < 16 mg/ml). SICs were performed with aqueous extracts of lysozyme (n = 4), ovalbumin (n = 2) and ovomucoid (n = 1), which elicited isolated early asthmatic reactions in all subjects. Double-blind, placebo-controlled, oral challenge tests with raw egg white were positive in three subjects.

CONCLUSIONS

These bakery workers had developed IgE-mediated occupational asthma to hen's egg white proteins.

[Angioedema due to sensitization to chicken meat]

BACKGROUND

Egg is the most frequent cause of food allergy in children. The bird-egg syndrome, found in a group of patients sensitized to egg through bird proteins, was infrequent in children. We report a patient with former history of hypersensitivity to egg who developed episodes of angioedema after ingestion of hen meat.

METHODS

Prick testing with egg and their different antigenic protein fractions, alpha-livetin and chicken meat was performed. Antigens of hen meat were used for the skin prick test and prick-by-prick. Serum-specific IgE was identified with use of the CAP techniques and SDS-PAGE Immunoblotting.

RESULTS

Prick test was positive with egg yolk, alpha-livetin and chicken meat. A prick-by-prick test with hen meat resulted positive in our patient, but the same test in four controls patients were negative. Serum specific IgE was positive for egg yolk and hen meat.

CONCLUSION

Allergy reactions to hen meat are exceptional. We report a case of children with allergy to egg proteins and hen meat that suggest an IgE mediated hypersensitivity reaction. Skin test reveal sensitivity to egg yolk and alpha-livetin, but this pattern of sensitization was infrequent in children.

Evolving role of the atopy patch test in the diagnosis of food allergy

The atopy patch test has developed into a valuable additional tool in the diagnostic work-up of food allergy in infants and children with atopic dermatitis. A positive atopy patch test may help to prevent imposing restrictive and unnecessary diets after misjudging late reactions by clinical assessment alone. Furthermore, the combination of positive atopy patch tests together with defined levels of specific IgE makes double-blind, placebo-controlled food challenges superfluous in some cases. However, several open questions indicate the need for further studies.

The "egg-egg" syndrome: occupational respiratory allergy to airborne egg proteins with consecutive ingestive egg allergy in the bakery and confectionery industry

Allergies to various inhalative allergens are a serious problem in the bakery and confectionery industry. Sensitization to wheat flour and enzymes such as alpha-amylase are a frequent cause of occupational asthma. Airborne egg allergens have been reported as another cause of respiratory allergy. We examined bakery and confectionery workers with respiratory symptoms due to egg aerosols. Skin tests (SPT), scratch tests (ST), nasal provocation tests (NPT) and serological examinations (IgE) were performed. Lung function was assessed by spirometry, and continuous registration of aerosols and particulates as well as gravimetric sampling was done at the workplace. Four bakery and two confectionery workers intensively exposed to airborne egg proteins suffered from conjunctivitis and rhinitis, four also from asthma. Subsequently, three of these four workers reported symptoms after ingestion of food that contained egg. SPT with commercial egg white and egg yolk extracts were negative in four cases. Only two employees had clearly positive SPT to commercial egg allergens and reacted also to wheat flour extracts. Scratch tests with native egg proteins were positive in four employees. Specific IgE to egg white and egg yolk were positive (CAP > or = 2) in three and in four cases, respectively, whereas they were negative in two cases. Elevated levels of specific IgE to lysozyme were detected in four employees. Two workers were sensitized to lysozyme but not to other egg proteins. The clinical relevance of egg sensitization was confirmed by continuous air sampling and by correlating the onset of the respiratory symptoms which were reflected by a significant decline (> or = 30%) of the forced one second capacity (FEV1) in two workers. Sieving of egg white powder and an inadequate spray station for liquid eggs were identified as sources of excessive allergen exposure. Bakery and confectionery workers exposed to airborne egg proteins are at risk of developing occupational asthma and subsequent nutritive egg allergy. To our knowledge, these are the first cases of inhalative egg allergy and subsequent nutritive egg allergy reported in the literature, which we refer to as the "egg-egg syndrome" in analogy to the already known "bird-egg" and "egg-bird" syndromes.

Validity of specific IgE antibodies in children with egg allergy

BACKGROUND

The demonstration of specific IgE antibodies to egg supports the existence of allergy to this food, but a correct diagnosis can only be obtained after a challenge test. Several studies have assessed different cut-off points in the level of these antibodies as predictors of clinical reactivity.

OBJECTIVE

Validation of the specific IgE antibodies measured by the CAP System Fluorescence enzyme immunoassay (FEIA) technique in the diagnosis of egg allergy in children under 2 years of age.

METHODS

A prospective study of 81 children with suspected egg allergy was performed. Specific IgE antibodies was quantified for egg white, egg yolk, ovoalbumin and ovomucoid. The diagnostic challenge test was carried out following the previously established criteria. The validity of the specific IgE antibodies was analysed using children with a negative diagnostic challenge test as control group.

RESULTS

The prevalence of egg allergy in the group studied was 79% and egg white was the allergen that showed the greatest diagnostic efficacy. The sensitivity and positive predictive value of the prick test and of the CAP to egg white were excellent and the specificity and the negative predictive value had lower values. A level of > or = 0.35 KU(A)/L for specific IgE antibodies to egg white predicted the existence of reaction in 94% of the cases.

CONCLUSIONS

Quantification of the specific IgE antibodies to egg white is useful in the diagnosis of egg allergy. In children under 2 years of age with a background of immediate hypersensitivity after egg ingestion and presence of specific IgE antibodies to egg white of > or = 0.35 KU(A)/L, diagnostic challenge test is not necessary to establish the diagnosis of allergy to this food.

Food allergens

A number of advances in the scientific knowledge concerning adverse food reactions have been made in the past few years. Understanding about the nature of the food allergen itself, the molecular characterization of the epitopes on these allergens, the pathophysiology of the clinical reaction, and the diagnostic methods have all been significantly enhanced.

[A case of allergy due to the use of an egg yolk vehicle in artificial insemination]

A case of allergy resulting from the employment of citrated homogenized egg yolk in homologous insemination is reported. The allergen was identified with the presence of egg yolk in the insemination vehicle. The various primary and secondary causes of the syndrome are discussed and the medical therapy used is described. It is suggested that intradermal skin reaction test be carried out with the individual components of the vehicle before artificial insemination with egg yolk-based vehicles is performed.