Egg allergy and yellow fever vaccination

Abstract Objective Evaluate biomarkers capable of safely guiding Yellow fever vaccine (YFV) vaccination among individuals suspicious of hen's egg allergy, and identify factors associated with a higher risk for adverse events after immunization (AEAI). Methods Patients underwent skin prick test (SPT) for standardized allergens: whole egg, egg white, egg yolk; YFV (1:10 dilution; Biomanguinhos-Fiocruz), and intradermal test (IDT; YFV 0.02 mL, 1:100 dilution) and positive and negative controls. Serum levels of specific IgE (sIgE) for a whole egg, egg white, egg yolk, egg albumin, ovomucoid, lysozyme, and conalbumin (ImmunoCap®; ThermoFisher®) were obtained. Patients sensitized to YFV were submitted to YFV desensitization, and those negatives received YFV (0.5mL) and remained under surveillance for at least one hour. Results 103 patients were enrolled, 95% under 12 years old. 71% (81/103) of patients had reactions: 80% immediate, 11% mixed, and 9% delayed. There was an association between positive skin test results with YFV and the severity of the reaction (OR:7.64; 95%CI:1.61-36.32; p =0,011). Only the presence of sIgE to ovomucoid was associated with clinical symptoms (p =0,025). Thirty patients underwent the YFV desensitization protocol. Conclusion There is a relationship between the positivity of the egg's components and the severity of the clinical reaction. Furthermore, the relationship between the positivity of the tests with the YFV and egg's components may show a tendency to look at ovomucoid and conalbumin, but it is not a certainty. Therefore, further studies are needed to confirm these associations, and for now, the authors still recommend using the vaccine for testing when necessary.

Update on egg allergy in children

Egg allergy is one of the most common food allergies in children and has a wide spectrum of clinical presentation including anaphylaxis. Many studies suggested egg-specific IgE cutoff values (diagnostic decision point) and skin prick test size that predict a clinical allergic reaction without oral food challenges. Some patients may react to all forms of egg including raw egg, but many egg-allergic patients tolerate baked egg products. A few studies reported that a high concentration of ovomucoid-specific IgE antibody indicates a high risk of reacting to heated egg white. Recently it has been suggested that regular ingestion of baked egg products may hasten tolerance development. Egg allergy may be more persistent than previously thought. The treatment of egg allergy still relies on dietary avoidance of egg-containing foods until tolerance has developed. In recent years there has been increasing success in clinical trials of egg oral immunotherapy, and oral immunotherapy can be a promising treatment modality for providing protection from reactions caused by accidental egg exposure. However, concerns regarding the safety and long-term efficacy still preclude the general use of oral immunotherapy in clinical practice. In this article, the recent literature regarding egg allergens, clinical presentation, diagnosis, management and natural history of egg allergy will be reviewed.

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.

The Influence of the Time and Temperature of Heat Treatment on the Allergenicity of Egg White Proteins

PURPOSE: The present study was performed to determine the factor, either duration or the temperature of heat treatment, exerting maximal and significant influence on the composition and allergenicity of egg white (EW) proteins. METHODS: Raw EW and 4 kinds of heated EW (fried EW, boiled EW for 10 minutes, boiled EW for 30 minutes, and baked EW for 20 minutes at 170degrees C) were prepared, and subsequently protein extraction was carried out. The proteins were separated by SDS-PAGE, and then immunoglobulin E (IgE) immunoblots were performed with the sera of 7 egg-allergic patients. Furthermore, the antigenic activities of ovalbumin (OVA), ovomucoid (OM), and ovotransferrin (OT) in different EW samples were measured by inhibition enzyme-linked Immuno-sorbent assay (ELISA). RESULTS: In SDS-PAGE analysis, the intensity of the protein band at 45 kD (corresponding to OVA) decreased significantly in boiled EW (30 minutes) and baked EW, but no change was observed in the case of boiled EW for 10 minutes. In IgE immunoblots, the IgE response to 34-50 kD (OM and OVA) in boiled EW for 30 minutes decreased significantly, when compared with raw EW and other heated EWs. In inhibition ELISA, a significant decrease in the OVA antigenic activity was observed in boiled EW for 30 minutes amongst other heated EW samples. However, OM antigenic activity in all kinds of heated EW including boiled EW for 30 minutes did not reduce after heat treatment. The OT antigenic activity nearly disappeared in heated EWs except in the case of boiled EW for 10 minutes. CONCLUSIONS: Amongst 4 kinds of heated EWs, the boiled EW for 30 minutes showed the most significant changes both in composition and reduction in allergenicity. Our results revealed that the duration of heat treatment had more influence on the composition and allergenicity of EW proteins than the temperature.

The Influence of the Presence of Wheat Flour on the Antigenic Activities of Egg White Proteins

PURPOSE: It is known that ovomucoid, an egg allergen, is heat resistant and remains soluble after heating. However, a recent study showed that the antigenic activity of ovomucoid could be reduced by heating when egg white (EW) was mixed with wheat flour. This study was performed to determine the influence of wheat flour on the antigenic activities of EW proteins when EW is heated, and the influence of the duration of heat treatment. METHODS: A mixture of EW and wheat flour was kneaded for 10 minutes and then baked at 180degrees C for 10 minutes and 30 minutes. The EW without wheat flour was also heated at 180degrees C for 10 minutes and 30 minutes. The proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and IgE immunoblotting was performed with the pooled sera of 5 egg-allergic patients. The antigenic activities of ovomucoid in different EW samples were measured by inhibition enzyme-linked immunosorbent assay (ELISA). RESULTS: 1) SDS-PAGE: the intensity of the 37-50 kD bands (overlapped bands of ovomucoid and ovalbumin) decreased significantly in the mixture of EW and wheat flour baked for 30 minutes, compared with the mixture baked for 10 minutes, heated EW and raw EW. 2) IgE immunoblot: in the mixture of EW and wheat, a remarkable decrease of IgE reactivity to 37-50 kD was observed when baked for 30 minutes. 3) Inhibition ELISA: the antigenic activity of ovomucoid decreased significantly in the mixture of EW and wheat baked for 30 minutes, but not in the heated pure EW. CONCLUSIONS: This study showed that the antigenic activity of ovomucoid can be reduced by baking EW with wheat flour. The decrease in ovomucoid antigenicity in the baked mixture of EW and wheat flour was dependent on the time of heat treatment, indicating that heating should be prolonged to achieve a reduction in ovomucoid antigenic activity.

Characterization of an Avian Protease Inhibitor.

Ovomucoid is a serine proteinase inhibitor in the egg whites of all avian species at a concentration of about 10 mg/ml. The involvement of proteinases in a multitude of control functions in an organism has created an interest in their physiological inhibitors. Regulation of proteolytic activity in tissues is a critical requirement in the maintenance of homeostasis. Egg white proteins possess ACE-inhibitory activity, & also high radical-scavenging activity. The combined antioxidant and ACE-inhibitory properties of egg white hydrolysates, or the corresponding peptides, would make a useful multifunctional preparation for the control of cardiovascular diseases. Proteases play key roles in several physiological processes, including intracellular protein degradation, bone remodeling, and antigen presentation, and their activities are increased in pathophysiological conditions such as cancer metastasis and inflammation. They are also required for invasion by microorganism. Four protease inhibitors have been identified in egg white: cystatin, ovomucoid, ovomacroglobulin (also known as ovostatin), and ovoinhibitor. Use of proteinase inhibitors in the treatment of certain diseases has renewed interest in their specificity and stability, both of which in turn depend on the tertiary structure of the inhibitor. Structural alteration to obtain molecules of desired properties requires knowledge of relationship between structure, function and stability. Aims: In view of its importance, in the present study duck ovomucoid was isolated and characterized for its physicochemical properties. Methodology: Duck ovomucoid was isolated and characterized for its physicochemical properties. Analytical gel filtration (Sephacryl S-100 HR column) was used for purification, determination of molecular weight (MW), carbohydrate content and Stokes radius.

Gene cloning,prokaryotic vector constructing for the major allergen ovomucoid in Hen's egg white and its recombinant expression / 中国免疫学杂志

Objective:To clone and express the gene of ovomucoid,which is the main allevgen in egg white.Methods:Using total RNA of chicken oviduct as template,the gene of ovomucoid was amplified by RT-PCR.The homology was analyzed by comparision with the sequence in GeneBank.Subsequently,the PCR product of the ovomucoid gene was cloned into prokaryotic expressing vector pET-28a and was expressed by the challenge of IPTG.Results:The whole gene of ovomucoid,one of the main allergens in egg white,was successfully cloned.The cloned ORF sequence contains 633 bp,including stop codon,encods for 210 amino acids.Sequence analysis shows that the ovomucoid gene displays 99% nucleotide identities with the published sequences.The molecule weight of ovomucoid protein obtained was 21 kD.By the challenge of IPTG,SDS-PAGE analysis showed that the ovomucoid gene was overexpressed in E.coli BL21(DE3).Conclusion:The gene of ovomucoid is cloned and overexpressed in E.coli BL21(DE3).This study will be the basis for the further research.

Homologous structural domains in chicken egg-white ovomucoid: Characterization and acid denaturation.

The primary structure of ovomucoid shows considerable sequence homology at three contiguous regions which form structural domains I, II and III. In order to see whether or not the three domains fold similarly and acquire similar overall native conformation/shape, two fragments A and C were obtained by controlled peptic digestion of ovomucoid. The two fragments were investigated for their chemical composition, molecular weight, anti-tryptic activity, hydrodynamic behaviour, optical properties and acid denaturation. Results on molecular weight, amino acid composition and inhibitory acitivity show that the fragments A and C correspond respectively to domain I-II and domain III. Optical data suggested more exposure of tyrosine residues in the fragments than in the intact molecule. Domain III exists in a compact and globular conformation under native conditions whereas domain I-II and ovomucoid appear to possess asymmetric conformation. Results on acid denaturation show that the process is thermodynamically reversible and that inter-domain separation probably precedes denaturation of domains during acidification of ovomucoid.

RAPID PURIFICATION OF WHEAT GERM AGGLUTINSN FROM WHEAT GERM / 第二军医大学学报

Wheat germ agglutinin(WGA)with a higher activity of hemagglutination was purified from wheat germ by a modified method of ovomucoid-Sepharose 4B affinity chromatography.The average yield of purified WGA from 100g wheat germ acetone powder was 58.74?6.56mg. WGA showed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an apparent molecular weight of 34400.The specific haptens of WGA- were N-acetylglucosamine and sialic acid.