Control of airborne and liquid-borne fungal and pet allergens using microwave irradiation

In this study, the dog, cat allergens (Can f 1 and Fel d 1) and fungal allergens (Alt a 1 and Asp f 1) were aerosolized and exposed to the microwave irradiation (2450 MHz) at different output powers for up to 2 min. The allergen bioaerosols were collected by a BioSampler, and analyzed using enzyme-linked immunosorbent assay (ELISA). Control and microwave-irradiated Asp f 1 allergens were also tested with IgEs in human blood sera samples. For airborne Asp f 1 and Alt a 1 allergens, the allergenicity was shown to decrease about 50% when exposed to microwave irradiation at 385 and 119 W and relatively no change at 700 W. For airborne Can f 1 allergen, the allergenicity was shown to increase about 70% when exposed to the irradiation at 385 W, but remained relatively unchanged at 700 and 119 W. In contrast, airborne Fel d 1 allergen was observed to lose allergenicity completely at 700 W, and retained about 40% and 80% at 385 and 119 W, respectively. Radioallergosorbent (RAST) tests showed that changes detected in IgE levels in human blood sera mixtures were not statistically significant for the control and microwave-irradiated waterborne Asp f 1 allergens. This study implies that although certain allergenicity reductions were observed for some allergens in certain cases, particular care should be taken when the microwave irradiation is used to disinfect food, water, and air because of its complex effects.

Ovalbumin modified by gamma irradiation alters its immunological functions and allergic responses

It is well known that gamma (gamma)-ray irradiation results in the alteration of biological function of bioactive materials such as proteins, saccharides and lipids. In this study the effect of gamma-irradiation on the chemical and immunological property of an allergen, ovalbumin (OVA), was investigated. Irradiation of more than 10 kGy resulted in the alteration of the structure of OVA. However, OVA treated with 10 kGy irradiation (10 kGy-OVA), but not 100 kGy-OVA, fully maintained immunological reactivity to a monoclonal antibody specific to the intact allergen (clone 14). Mice immunized with 10 kGy- as well as 100 kGy-OVA showed significantly lower antibody response to the allergen than those with intact OVA in a gamma-ray dosage-dependent manner. Especially immunization of both 10 kGy- and 100 kGy-OVA induced a significant decrease of OVA-specific IgE. Splenocytes of mice immunized with irradiated OVA showed a significant reduction in OVA-specific T cell proliferation and the secretion of Th1-type (IFN-gamma and IL-2) and Th2-type cytokines (IL-4 and IL-6). The expression of T cell activation markers such as CD25 and CD44 was also down-regulated in T cells of mice immunized with irradiated OVAs. These results suggest that gamma-ray irradiation of OVA suppress humoral and cellular immune responses specific to the allergen OVA, and the modification method with gamma-irradiation may be available for the control of allergy.

Microbial population, physicochemical quality, and allergenicity of molluscs and shrimp treated with cobalt-60 gamma radiation

Frozen molluscs (squid, octopuses, and cuttlefish) and crustaceans (shrimp) were irradiated using a cobalt-60 gamma source, at different doses, in order to investigate the effects of gamma radiation on their microbial population, organoleptic characteristics, lipid profile, and tropomyosin content. Irradiation of shrimp and squid with either 2.5 or 4.7 kGy reduced mesophilic bacteria contamination to low or nondetectable levels, respectively, whereas irradiation of octopus and cuttlefish with the same doses reduced the bacterial population. Irradiation treatment had no significant (P > 0.05) effect on the total lipid content and the major detected classes of polar and neutral lipids, whereas it significantly (P < 0.05) increased the contents of neutral lipids in octopus mantle and in shrimp muscle and cephalothorax samples. The total fatty acid content and the omega-3: omega-6 fatty acid ration was not affected. A dose-dependent significant (P < 0.05) decrease in the ratio of polyunsaturated fatty acids:saturated fatty acids was observed. With the increase in radiation dose, redness (a) and yellowness (b) values showed a variation, whereas the lightness (L) value was significantly (P < 0.05) decreased in mollusc mantles and shrimp muscle and increased in shrimp cephalothorax. The total of color changes ( delta E) increased (P < 0.05) as the dose increased. Significant (P < 0.05) changes in textural properties were observed with radiation treatment in octopus tentacles and in squid and cuttlefish mantle. The amount of tropomyosin, which is the major mollusc and crustacean allergen in the irradiated organisms, was reduced by gamma radiation, depending on the dose.

[Results and assessment of photopatch testing in Spain: towards a new standard set of photoallergens]

INTRODUCTION

While the standardization of exploration with photoallergy tests or photopatch testing runs its course in Europe, we have carried out an epidemiological study about the current situation of photoallergy in our country.

MATERIAL AND METHODS

We have gathered the results of photopatch testing in seven hospital centres of Madrid, Cataluña, Galicia and Comunidad Valenciana during the years 2004 and 2005. The exploration has included, at least, the standard set of the Spanish Photobiology Group (GEF), with 16 (photo) allergens, that have been irradiated with 10 joules/cm(2). We have assessed the total number of explored patients, their sex, present, past or unknown relevance of positive photopatch testing, cross reactions, and allergens responsible for photosensitization.

RESULTS

Of 224 patients explored by photopatch testing, 39.3 % show one or more positive tests. Seventy-one percent (103) were considered relevant with respect to clinical history, 14 cases (9.6 %) were cross reactions, and 28 (19.3 %) were considered of unknown relevance. The most prevalent allergens were nonsteroidal antiinflammatory drugs, specially ketoprophen (43 patients), followed by bencydamine (7 patients) and etofenamate (5 patients). The mixture of four sunscreens from the standard set of the GEF only detected 10 of 16 patients with photoallergy to sunscreens. Photopatch testing of unknown relevance was mainly due to antiseptics (fenticlor) and topical antihistamines.

CONCLUSIONS

We propose the modification of the standard set of photoallergens from the GEF, that should include the majority of nonsteroidal antiinflammatory drugs and sunscreens available in Spain. Ketoprophen continues to be the most frequent photoallergen in our country. It is also important for the cross sensitizations that may present. Sunscreens should be explored separately and not in form of a mixture.

Deleterious effects of electron beam radiation on allergen extracts

BACKGROUND

The recent threat to the public posed by the dissemination of Bacillus anthracis through the US postal system has resulted in increased security measures, including electron beam irradiation for the sterilization of some mail. The deleterious effects of electron beam radiation on biological products are not fully understood.

OBJECTIVE

The purpose of this investigation was to assess the effect of electron beam radiation, as currently used to sterilize packages and mail in the United States, on several standardized or characterized allergen extracts.

METHODS

Selected irradiated extracts were analyzed for allergen content and potency by SDS-PAGE, immunoblot, and ELISA (including inhibition) and compared with untreated extracts.

RESULTS

The compositions and immunochemical potencies of these products were altered significantly by irradiation treatment. Physical changes to native protein structures observed after electrophoretic separations coincided with near-complete loss of allergenic and antigenic epitopes present on major and minor allergens, according to ELISA and immunoblot comparisons with untreated extracts.

CONCLUSIONS

These results indicate that extracts subjected to electron beam sterilization conditions are likely to contain modified component structures and properties that might compromise the clinical effectiveness of these products.

Effects of gamma radiation on the allergenic and antigenic properties of milk proteins

This study was carried out to evaluate the application of food irradiation technology as a method for reducing milk allergies. Bovine alpha-casein (ACA) and beta-lactoglobulin (BLG) were used as milk proteins. Using milk-hypersensitive patients' immunoglobulin E (IgE) and rabbit IgGs individually produced to ACA and BLG, the changes of allergenicity and antigenicity of irradiated proteins were observed by competitive indirect enzyme-linked immunosorbent assay. Allergenicity and antigenicity of the irradiated proteins were changed with different slopes of the inhibition curves. The disappearance of the band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and increase of the turbidity showed that solubility of the proteins decreased by radiation, and this decrease might be caused by agglomeration of the proteins. These results indicated that epitopes on milk allergens were structurally altered by gamma irradiation.

Effects of gamma radiation on the conformational and antigenic properties of a heat-stable major allergen in brown shrimp

This study was performed to evaluate the application of food irradiation technology as a method for reducing shrimp allergy without adverse effects. Shrimp heat-stable protein (HSP) was isolated and gamma irradiated at 0, 1, 3, 5, 7, or 10 kGy in the condition of solution (1 mg/ml), and fresh shrimp was also irradiated. Conformational change of irradiated HSP was monitored by means of spectrometric measures, enzyme-linked immunosorbent assay with mouse monoclonal antibody, or human patients' sera and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The ability of the immunoglobulin E of patients allergic to shrimp to bind to irradiated HSP was dose dependently reduced. The amount of intact HSP in an irradiated solution was reduced by gamma irradiation, depending on the dose. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the main band disappeared and the traces induced from coagulation appeared at a higher molecular weight zone. The binding ability of immunoglobulin E to allergens in the extracts from irradiated shrimp decreased, depending on the dose. The results provide a new method so that food irradiation technology can be applied to reduce allergenicity of shrimp.

Use of the occlusive patch to evaluate the photosensitive properties of chemicals in guinea-pigs

Guinea-pig tests were conducted on a known photocontact allergen, tetrachlorosalicylanilide (TCSA), a known phototoxin, 8-methoxypsoralen, two reportedly weak photoallergens, musk ambrette and 6-methylcoumarin, and a negative control, octylphenoxy polyethoxyethanol (Triton X-15). The data show that under the test conditions used, photosensitivity responses can be produced, and combinations of these as well as the other biological responses can be readily defined. The results indicate that musk ambrette is photoallergenic, that 8-methoxypsoralen is phototoxic and that Triton X-15 is only a slight irritant. On the other hand, results with TCSA suggest that it is a strong contact allergen and photoallergen, while 6-methylcoumarin would be considered to be a weak contact allergen with weak phototoxic properties. Previous reports that barrier destruction or adjuvanticity is necessary to produce photoallergy to musk ambrette were not confirmed; by ensuring occlusion using standard methods, the photoallergic nature of the response to this material was clearly demonstrated. A device described elsewhere (Newmann & Parker, Fd Chem. Toxic. 1985, 23, 683) has made it possible to develop methods that can be used to differentiate clearly among the possible biological responses that can occur in guinea-pigs when photoreactive materials are applied to their skin and irradiated. The probable biological responses that need to be defined, under the above conditions, are primary irritation, delayed contact hypersensitivity, phototoxicity and/or photoallergenicity.

Effect of ultraviolet irradiation of photopatch test substances in vitro

The mechanisms behind allergic photocontact reactions are not clear. For certain photoactive substances the generation of photoproducts may be one step in the sequence of events inducing photoallergy. 26 photoactive substances were studied by thin layer chromatography (TLC) before and after long-wave or medium-wave ultraviolet irradiation for 1, 3 and 5 h (10.8, 32.4, 54 J/cm2 and 1.1, 3.2, 5.4 J/cm2). The formation of photoproducts was demonstrated for 13 substances. For 8 of these, photoproducts were formed regardless of type of ultraviolet exposure while for 5 compounds photoproducts were demonstrated only after long-wave ultraviolet irradiation. All photoactive compounds forming photoproducts did so after UVA irradiation which is in accordance with the finding of action spectra for photoallergic reactions in human skin within this region. No photoproducts were demonstrated for 13 of the tested substances.

Denaturization of allergen P: effect on allergenicity, antigenicity and immunogenicity

When allergen P was denatured by 8M urea, the modified molecule still reacted with IgE specific for the native allergen but not with hemagglutinating antibodies. Heating at 100 degrees C abolished the reaction in both cases. The results suggested differences between allergenic and antigenic capacities which may be based on structural differences of the antigenic determinants.

Animal dander allergy

In a group of twenty-three atopic patients skin tests were performed with the dander allergens of horse, cat and guinea-pig, and with house dust and Timothy pollen allergens. A good agreement was observed between positive skin reactions and the results of RAST with these various allergens. In a number of cases, positive skin reactions were not related to the clinical histories. Likewise, positive RAST scores in several instances proved clinically meaningless. In patients with history-related skin reactions better correlation with RAST was observed. In such patients, skin reactions with photo-inactivated allergens remained strongly positive.

Immediate hypersensitivity to cockroach. Isolation and purification of the major antigens

Crude cockroach extract elicited positive skin tests in 50% of patients with positive and in 4% with negative environmental history for cockroach exposure, suggesting a possible role of cockroach in perennial atopic disease. Three major allergens in crude American and German cockroach extracts have been identified using sequential purification steps on Sephadex G-75, diethylaminoethyl (DEAE) cellulose, and agarose gel electrophoresis. Cr-I elicits positive skin tests in 70% of patients sensitive to the crude extracts. It has a molecular weight of approximately 25,500 daltons, is highly acidic, and resists boiling for four hours. Boiling in 4 N acetic acid completely abolishes its allergenicity. The purified allergen elicits positive skin tests at a concentration of 3 mug/ml and is capable of inducing greater than 50% histamine release from sensitive leukocytes at 0.05 ng/ml. A second antigen, Cr-II, elicits positive skin tests also in approximately 70% of cockroach-sensitive individuals, has a molecular weight of approximately 63,000 to 65,000 daltons, and has similar heat stability and acid hydrolysis characteristics to Cr-I. A third, less well-characterized antigen, Cr-III, has a molecular weight less than 10,000 daltons and elicits positive skin tests in 30% of individuals sensitive to the crude extract.