Characterization of Bovine Whey Proteins by Crossed Immunoelectrophoresis

The antigenicity and allergenicity of microparticulated proteins: Simplesse

New technologies are allowing the food industry to develop products from standard foods which may not be recognized in its modified form by food allergic patients. One such product, Simplesse, has been formulated by microparticulation of egg white and/or cows' milk proteins and is used as a fat substitute in many fat-laden foods. The purpose of this study was to determine whether the process of microparticulation altered the allergenicity/antigenicity of egg white and cows' milk proteins compared to the starting materials. Soluble protein fractions of Simplesse and its respective starting materials were compared to egg white, cows' milk protein, an ultra-filtered egg white/condensed milk mixture, and/or a whey concentrate by SDS-polyacrylamide gel electrophoresis. In addition, sera from 16 patients with documented egg and/or cows' milk hypersensitivity and two controls who were not allergic to egg or milk were used to assess potential allergenicity/antigenicity of these products by immunoblot (Western blot) analysis. There were heterogeneous IgE and IgG binding patterns to the food fractions among these food allergic patients suggesting differing sensitivity patterns among the individuals tested. However, utilizing both SDS-PAGE and immunoblot analyses, the major allergens in the microparticulated products were the same as those found in the starting materials, egg and cows' milk. In addition, there was no evidence of 'novel' protein fractions in the Simplesse test materials compared to the starting materials.

Basophil histamine release in insect venom allergy

The aim of the present study was to investigate venom-related and venom-non-related immunological reactions in patients stung by bee or wasp. Sixteen consecutive patients (7 with local and 9 with systemic reactions) were tested with skin tests, RAST and basophil histamine release (BHR) test immediately after the insect sting and 2, 4, and 16 weeks later. No test was useful immediately after the insect sting, the "anergic period". In agreement with earlier findings, the SPT was the only allergy test that showed statistically significant differences between patients with local and systemic reactions, although a great overlap was found. Release of histamine from basophils after incubation with anti-IgE also showed statistically significant differences between local and systemic reactions. Further studies are needed, especially measurement of BHR after incubation with anti-IgE before insect stings.

Demonstration of species-specific sensitization to major allergens of Dermatophagoides species by solid-phase absorption of human IgE antibodies

Twenty-five mite-allergic patients in the Brussels area were tested with the skin-prick test (1, 5 and 10 histamine equivalents by prick test (HEP] and RAST with standardized extracts of Dermatophagoides pteronyssinus (Dp) and D. microceras (Dm). Highly significant correlations (0.69 less than rS less than 0.96) between the two species coincided with marginal, but highly significant (P less than 0.01), greater reactions to Dp in all comparisons. Species-specific IgE antibodies to antigen Dp-42 (= P1) and Dp-X were readily detected by solid-phase serum absorption with heterologous antigen and subsequent crossed radioimmunoelectrophoresis (CRIE). An absorption single radial immunodiffusion (SRID) technique, involving major allergens Dp-42, Dm-6 and Df-6 of Dp, Dm and D. farinae (Df), demonstrated the presence of IgE antibodies reacting with epitopes common to all species, epitopes common to two species, absent on the third, and epitopes strictly specific for Dp. The majority of patients with a strong IgE binding reacted to both common and strictly species-specific epitopes. The serological findings were in good agreement with the exposure situation in the area: by species-specific ELISA for dust allergen content, Dp occurred as the dominating species, 20 out of 24 homes having dust levels of Dp-42 above 30 ng/g. Five and four homes had detectable levels of Dm-6 and Df-6, respectively, in dust.

Allergen-specific IgE antibodies against antigenic components in cow milk and milk substitutes

Crossed radioimmunoelectrophoresis (CRIE) was used to study the presence of serum IgE against antigenic components of cow milk in 21 selected milk-allergic patients. The amount of each IgE specificity was estimated by a scoring system. The milk-allergic children had mainly IgE against alpha-lactalbumin, beta-lactoglobulin, albumin and immunoglobulin, the four major proteins of bovine whey, as well as IgE against three casein components. A serum pool from 1000 normal adults had IgE against the same whey protein, but in smaller amounts, and no IgE against the casein components. Eight cow milk-based formulae, commonly used for infant feeding, and goat milk were studied by the same method. It was found that six of the milk substitutes did not differ significantly from cow milk in antibody binding, but the two hydrolysed casein products, Nutramigen and Pregestimil, consisted of such small molecules that the rabbit antisera could not precipitate the hydrolysed proteins in the gels on the CRIE plates. It was therefore not possible to study their IgE binding, if any, by this method.

Purification of patient-related allergens by means of bioaffinity chromatography on a sepharose anti-IgE patient IgE immunosorbent

A method is described for bioaffinity chromatographic purification of patient-specific IgE reactive allergens by using sepharose coupled rabbit anti-human IgE antibodies, patient serum and an allergen extract. The conditions for this bioaffinity chromatographic procedure have been optimised, and it was shown that the nonspecific binding of serum proteins and antigens can be kept at very low levels by a high ionic strength. The specificity of the method has been determined by showing that allergens to which the patient did not react were not bound to the affinity matrix. We suggest that the isolated allergens could be used for more specific immunotherapy in the future.

Bacterial histamine release by immunological and non-immunological lectin-mediated reactions

The mechanisms of bacteria-induced histamine release were examined in vitro in human leukocytes and rat mast cells. Three types of bacterial responders were found. In persons with IgE-bearing basophilocytes bacterial histamine release could be triggered by two different mechanisms, an IgE-dependent mechanism where removal of IgE abolished the release and a non-immunological mechanism where this was not the case. In responders with no IgE-bearing cells bacterial histamine release was caused by a non-immunological mechanism. The non-immunological mechanism was further substantiated by release in isolated mast cells from germ-free rats. These experiments suggest a direct interaction between bacteria and target cell, and experiments with multi-washed bacteria and bacteria cell wall preparations indicate the possibility of the bacteria wall interacting with the target cell. It is probable that the non-immunological mechanism depends on lectin-mediated reactions, since bacteria-induced histamine release was inhibited by lectin-binding sugars as is release caused by plant lectins.

Hypersensitivity to foods among birch pollen-allergic patients. Immunochemical inhibition studies for evaluation of possible mechanisms

Several statistical investigations have indicated that an immunological partial identity might exist between birch pollen an some foods because of the existence of concurrent hypersensitivity symptoms to both sources. In order to study this, two groups of BP (birch pollen)-allergic patients (20 with (F+) and 20 without (F-) food hypersensitivity) were skin prick tested with extracts of various foods prepared in different ways. Sera from these patients were inhibited with different foods, including a lectin, Con A (concanavalin A), before analysis in BP-RAST and -CRIE. Corresponding experiments using sera from grass pollen allergics were performed as controls. The two groups of patients showed identical skin reactivities to BP extract whereas the F+ patients bound twice as much BP-specific IgE in RAST and CRIE as the F- patients. BP-RAST performed with sera from F+ patients were in some cases inhibited with foods and Con A; corresponding BP-CRIE were not. Neither BP-RAST (with one exception) nor -CRIE performed with sera from F- patients were inhibited with foods and Con A. TP (timothy pollen)-RAST performed with sera from timothy allergic patients were inhibited with some foods and with Con A; corresponding TP-CRIE were not. Controls performed on sera from normal individuals revealed no inhibition at all in the BP and TP systems. As no direct evidence for immunological partial identity was found from these results the clinical hypersensitivity against some foods among BP-allergics are discussed particularly regarding content of lectin in foods and common carbohydrate components in pollen allergens and food molecules.

Identification of allergens in Dermatophagoides pteronyssinus mite body extract by crossed radioimmunoelectrophoresis with two different rabbit antibody pools

An extract of purified Dermatophagoides pteronyssinus mite bodies was investigated by crossed radioimmunoelectrophoresis (CRIE), using sera from 29 mite-allergic patients. Two CRIE series consisting of rabbit antibodies to (1) whole mite culture and to (2) purified mite bodies were run simultaneously, showing 27 and 29 precipitates, respectively. Cases of major discrepancy between the two series were ascribed to absence of antibody to allergenic components and to artefactual radiostaining due to inclusion of allergen in precipitates representing other antigens. Carefully performed controls were necessary to establish the reliability of CRIE. Specific response patterns in the studied set of sera were found to several of the represented antigens. Two major allergens appeared in both CRIE systems. Two intermediate and several minor allergens were further identified.

Superoxide dismutase isoenzymes in bovine and human milk

The presence of superoxide dismutase in bovine and human milk was investigated by ultrafiltration, gel filtration, and isoelectric focusing. Conclusive evidence for the presence of this enzyme in both milks is presented. The molecular weight of the enzyme was estimated by gel filtration on Sephadex G-100 to be 30,000, which is consistent with reported values for the copper, zinc form of superoxide dismutase. In addition, enzyme activity was inhibited by cyanide, thus eliminating the possibility that the enzyme was present in the manganese form. Several isoenzymes were detected by isoelectric focusing in polyacrylamide gel, and the isoenzyme pattern in bovine milk was the same as that found for bovine plasma, suggesting that milk superoxide dismutase originates from plasma. It may be that the presence of copper, zinc superoxide dismutase in milk is important for the maintenance of its oxidative stability.

Type I allergy from cows in veterinary surgeons

Occupational contact dermatitis caused by obstetric work and/or contact with cows is common among veterinary surgeons. We examined serum from nine veterinary surgeons of whom seven gave a history of itching and flare of eczema after obstetric work and/or contact with cows. By means of crossed radioimmunoelectrophoresis the occurrence of specific IgE against cow hair and dander was demonstrated. The IgE did not differ qualitatively or quantitatively from IgE in serum from patients with allergic asthma from cows. Four veterinary surgeons with flare-up of eczema during obstetric aid to cows did not have assignable s-IgE against bovine amnion or allantoic fluids.

Quantitative immunoelectrophoretic analysis of extract from cow hair and dander. Characterization of the antigens and identification of the allergens

Quantiative immunoelectrophoresis used for the analysis of a dialysed, centrifuged and freeze-dried extract from cow hair and dander revealed 17 antigens. Five of these were identified as serum proteins. Partial identity to antigens of serum and extract from hair and dander of goat, sheep, swine, horse, dog, cat and guinea pig, and to antigens of house dust was demonstrated. Sera from 36 patients with manifest allergy to cow hair and dander selected on the basis of case history, RAST, skin and provocation test, were examined in crossed radioimmunoelectrophoresis (CRIE); sera from five persons with high serum IgE, but without allergy to cow hair and dander, and sera from five normal individuals were controls. 31/36 of the sera contained IgE with specific affinity for two of the antigens of the extract. Further, two major and six minor allergens were identified. The control sera showed no specific IgE binding. A significant positive correlation was found between RAST and CRIE for the first group of patients. The approximate molecular weights of the four major allergens obtained by means of gel chromatography were: 2.4 x 10(4), 2 x 10(4), 2 x 10(5) dalton, respectively. Using Con-A and Con-A Sepharose in crossed immunoaffinoelectrophoresis, eight of the antigens were revealed to contain groups with affinity for Con-A.

Characterization of extract of dog hair and dandruff from six different dog breeds by quantitative immunoelectrophoresis. Identification of allergens by crossed radioimmunoelectrophoresis (CRIE)

An extract of mixed dog hair and dandruff from six different dog breeds (alsatian, boxer, collie, poodle, and long-haired and short-haired dachshund) was obtained by mild extraction, centrifugation, dialysis and freeze-drying. Extract of hair and dandruff from the individual dog breeds was obtained in the same way, but the material was not freeze-dried. Examination and characterization of the mixed extract by means of crossed immunoelectrophoresis revealed a precipitation pattern composed of 25 antigens, some of which were mutually partially identical, and a high content of dog serum proteins was found. Quantitative and qualitative differences between the individual dog breeds were demonstrated. Partial identity of the antigens of the mixed extract with antigens of serum, antigens of extracts of hair and dandruff from cat, cow, horse and guinea pig, and antigens from extract of house dust was also observed. By means of crossed radioimmunoelectrophoresis, using sera from 21 patients who were RAST-positive to dog hair and dandruff extract, the specific IgE-binding to antigens of the mixed extract was examined. On the basis of these results major and minor allergens were identified. Dog albumin was found to be a very important major allergen, but alpha1-antitrypsin and gamma-globulin were also identified. Furthermore, four non-serum proteins were shown to be allergens. No breed-specific allergens could be identified in the extracts from the individual dog breeds.