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Results for “Radioallergosorbent Test”

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PubMed1991

The prevalence of atopy and hypersensitivity to formaldehyde in pathologists.

Sixty-three pathologists in active practice in the province of Alberta, Canada, provided a history regarding atopy and sensitivity to formaldehyde. Serum samples were assayed for total IgE level and the presence of IgE with specificity toward timothy grass, cat, house dust, and formaldehyde. Twenty-nine of the subjects (46.0%) gave a history of atopy that was confirmed in 12 by either IgE level or a positive radioallergosorbent test. Twenty-nine (46.0%) complained of formaldehyde sensitivity. In this study, no pathologist had allergen-specific IgE directed against formaldehyde, and there was no evidence of a tendency for atopic subjects to be more prone to sensitivity to formaldehyde. However, this may be related to a deliberate reduction in exposure by individuals experiencing adverse effects.

Drug Hypersensitivity↗

PubMed1979

Assessment of the influence of irrelevant IgE on allergic sensitivity to two independent allergens.

Serum samples from 31 patients sensitive to both ragweed and rye grass were quantitated for IgE specific for ragweed antigen E (AgE) and rye grass group I (rye I) antigens employing the previously described radioallergosorbent test (RAST) elution technique. IgE anti-AgE ranged from 0.4 to 320 ng/ml and comprised 0.4% to 14.2% of total serum IgE. The same sera contained IgE anti-rye I ranging from 7.9 to 1,168 ng/ml, comprising 1.6% to 29.6% of total serum IgE. A new theoretical parameter (RF), representing the percent of total IgE-Fc receptors of target cells occupied by allergen-specific IgE, was calculated for each IgE specificity by using the determinations of allergen-specific IgE antibody, total serum IgE, and assuming an equilibrium constant for binding of IgE molecules to basophils of 10(9)M-1. This "% occupancy" parameter correlated with skin test titration, basophil cell sensitivity, and hay fever symptom scores as well as, but not better than, the absolute values of allergen-specific IgE. This finding suggests that in most atopic patients, the quantity of irrelevant IgE plays a relatively minor role in determining allergic sensitivity to a given allergen. The implications of this finding are discussed.

Allergens↗

PubMed1981

Anaphylaxis after sesame seed ingestion.

Four patients with histories of systemic anaphylaxis or angioedema and urticaria after ingestion of sesame seed or sesame oil-containing products were studied for anti-sesame seed extract IgE by the radioallergosorbent test (RAST). Three of four were found to be positive. RAST inhibition after density-gradient ultracentrifugation of sesame seed extract indicates that the most active allergens appear to have molecular weights between 8,000 to 62,000 daltons.

Adult↗

PubMed1992

[The antigenic and allergenic properties of an extract from the house dust mite Dermatophagoides farinae].

To evaluate the antigenic composition and allergenic activity of D. farinae extracts, the methods of rocket and cross immunoelectrophoresis, gel chromatography and the inhibition of the radioallergosorbent test have been used. The presence of 9-20 antigenic components has been established. The fractions of the extract with a molecular weight of 10-200 kD possessed the highest capacity of inhibiting the binding of specific IgE antibodies from the pool of sera from patients sensitized to D. farinae.

Allergens↗

PubMed1987

Recognition of a site of a Kentucky bluegrass pollen allergen by antibodies in the sera of allergic and non-atopic humans and a murine monoclonal antibody.

Allergen 27 was isolated from the aqueous extract of Kentucky Bluegrass pollen (KBG-R) with a reversed immunosorbent prepared by coupling murine monoclonal antibody, Mab 27, to Sepharose 4B. Sera of patients allergic to KBG pollen, as well as serum of nonatopic individuals possessing anti-KBG antibodies, inhibited the binding of Mab 27 to either Ag 27 or KBG-R to the extent of 20 to 35% in ELISA. In contrast, sera devoid of antibodies to KBG-R had no inhibitory capacity. In a radioallergosorbent test, it was demonstrated that Mab 27 could inhibit the binding of human IgE antibodies to Ag 27 to the extent of 52%. From these results, it is concluded that Ag 27 contains a determinant recognized by both human IgE and blocking antibodies and a murine Mab.

Allergens↗

PubMed1987

Crawfish and lobster allergens: identification and structural similarities with other crustacea.

Antigenic and allergenic components in crawfish and lobster extracts were studied using crossed immunoelectrophoretic techniques. Crossed immunoelectrophoresis with rabbit antisera revealed 23 antigens in crawfish and 17 antigens in lobster extracts. Both extracts exhibited structural similarities in antigens mutually and with other crustacea in cross-line immunoelectrophoresis. Crossed radioimmunoelectrophoresis (CRIE) demonstrated 6 crawfish and 4 lobster allergens when individual or pooled sera from radioallergosorbent test (RAST)-positive crustacea-sensitive subjects were used. Since radiostaining was also observed with sera from RAST-negative nonsensitive subjects, specificity of IgE binding was tested using CRIE-inhibition. Preincubation of RAST-positive sera with crawfish or lobster extract decreased radiostaining in CRIE, while no changes occurred when using control sera. These results confirmed the presence of IgE-mediated mechanisms in seafood allergy and demonstrated a number of shared antigenic determinants among crustacea allergens.

Allergens↗

PubMed1977

Allergens in Hymenoptera venoms. IV. Comparison of venom and venom sac extracts.

Honeybee venom sac extract is compared with pure venom. All five known allergens of venom are present in venom sac extract. Enzyme analyses indicate that the sac extracts contain 11% to 16% venom. At least 10 additional components, several of which are proteins, are present in venom sac extract. Radioallergosorbent test (RAST) studies of yellow jacket venom and venom sac extract yielded a correlation of r = 0.94, with only some weakly reactive sera positive to only one preparation. A few sera were substantially more reactive with venom sac extract. Venom sac extracts appear to be suitable for in vitro diagnostic use, but the extraneous proteins and peptides may make them less suitable than pure venoms for use in immunotherapy.

Acid Phosphatase↗

PubMed1977

Selective isolation of allergens. I. Reaction of house dust mite extracts with tridacnin and concanavalin A and examination of the allergenicity of the isolated components.

Tridacnin, a lectin from the clam Tridacna maxima was found to precipitate with crude extracts from the house dust mites Dermatophagoides farinae and Dermatophagoides pteronyssinus. Using tridacnin in direct precipitation and affinity chromatography studies, a carbohydrate-rich preparation of high molecular weight was isolated from D. farinae extracts. The isolated preparation gave one precipitin line when used with tridacnin in gel diffusion and immunoelectrophoresis experiments but two bands were seen on polyacrylamide disc gels after electrophoresis at pH 8.9. Radioallergosorbent test (RAST) studies demonstrated that the isolated material reacted strongly with sera from human subjects allergic to house dust mites and accounted for a significant proportion of the IgE binding capacity of the crude D. farinae extracts. Only one out of fifteen mite-allergic subjects gave a positive response when prick tested with the isolated preparation at a concentration of 0.2 mg/ml. A possible explanation for the discrepancy observed between RAST and skin test results is discussed. Concanavalin A also precipitated with D. farinae extracts but the material isolated with this lectin did not react with tridacnin and reacted weakly in the RAST with sera from mite-allergic subjects. We suggest that the high molecular weight component(s) which react with tridacnin may be useful for immunotherapy of house dust mite allergy.

Allergens↗

PubMed1985

Increased sensitivity and specificity of a sandwich ELISA for measurement of IgE antibodies.

We have developed a sandwich enzyme-linked immunosorbent assay (ELISA) for measurement of IgE antibodies to the bee venom allergens phospholipase A2 (PLA2) and hyaluronidase (HYAL). The assay is 10-20 times more sensitive than conventional indirect ELISA or radioallergosorbent test (RAST). Furthermore, by using affinity purified rabbit antibodies to these allergens, the specificity of the test was increased compared to RAST. The use of antibodies to link the antigen to the solid phase removes the dependence on the individual protein's ability to bind to the microtitre plate. The increased sensitivity of the sandwich assay seems to be due to better presentation and retention of antigen on the solid phase.

Antibody Specificity↗

PubMed1987

Clinical and immunological investigations of respiratory disease in workers using reactive dyes.

A questionnaire survey of over 400 workers handling reactive dyes showed that over 15% had work related respiratory or nasal symptoms. Forty nine employees with symptoms were referred to chest clinics for detailed assessment. It was considered that in 19 the symptoms could be attributed to an irritant response to a variety of chemicals, including hydrochloric acid vapour, sulphur dioxide, and reactive dyes. Symptoms in 24 were attributed to an allergic reaction to a specific agent; in most (21) to one or more reactive dyes. Two patterns of allergic lower respiratory symptoms were identified; an immediate response of short duration and a longer lasting response, usually of several hours, sometimes accompanied by nocturnal asthma. A radioallergosorbent test (RAST) screen containing the most commonly used reactive dyes was used to detect specific IgE. Allergic symptoms to reactive dyes were strongly associated with specific IgE (17/21 employees) and atopy (18/21). Irritant symptoms were also associated with atopy (13/19) but only weakly associated with specific IgE (7/19).

Coloring Agents↗

PubMed1983

Laboratory animal allergy: the measurement of airborne urinary allergens and the effects of different environmental conditions.

Casella Simquad air samplers, with 0.5 microM cut-off filters, were employed to sample the air in a laboratory animal house environment. The extracts obtained were assayed for laboratory animal urinary protein allergens using the inhibition radioallergosorbent test (RAST inhibition). The results showed that the collection and assay methods were of value and studies were extended to the influence of air change rates and humidity on airborne allergen levels. Reducing the air changes increased allergen levels, whilst increasing the humidity from 54% to 77% caused a significant reduction in allergen levels.

Aerosols↗

PubMed1984

Characterization of allergens in a crude extract of Dermatophagoides farinae and their identification in a new purified preparation.

The allergens of a crude D. farinae extract were identified by means of crossed radioimmunoelectrophoresis (CRIE). A total of 11 allergens were identified. They were characterized as three major, three intermediate and five minor allergens, based on radiostaining in CRIE. In addition to the radiostaining due to allergens, some misleading radiostaining was observed associated with some of the other antigens. A purified commercially available preparation, Spectralgen Mite D. farinae, was compared with the crude extract by means of immunoelectrophoretic techniques and radioallergosorbent test (RAST) based techniques. The purified preparation was found to be fully representative of the allergens in the crude extract. All 11 allergens were identified in the purified preparation. The purification ratio of the allergens varied from 2 to 7, while the total specific allergenic activity was approximately 6 times higher in the purified preparation than in the crude extract, as judged from RAST-inhibition studies.

Allergens↗

PubMed1989

Comparative analysis of physicochemical and immunochemical properties of the two major allergens from Dermatophagoides pteronyssinus and the corresponding allergens from Dermatophagoides farinae.

Two major allergens, DP1 (Der p I) and DP2 (Der p II), were isolated from the whole culture extract of Dermatophagoides pteronyssinus, and the physicochemical and immunochemical properties of these allergens were compared with those of the corresponding allergens from Dermatophagoides farinae, DF1 (Der fI) and DF2 (Der fII). On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, polyacrylamide gel isoelectric focusing and amino acid analysis, both DP1 and DP2 were demonstrated to have close physicochemical similarity with DF1 and DF2, respectively. On immunodiffusion with the use of rabbit antisera, the two Der I allergens showed the reaction of typical partial identity, while the two Der II allergens showed the reaction of almost complete identity. Radioallergosorbent test (RAST) and RAST absorption experiments with the use of sera from mite-allergic patients showed that human IgE antibody response to the Der I allergens was directed against both cross-reactive and species-specific determinants. In contrast, IgE antibodies to the Der II allergens were demonstrated to react almost completely to cross-reactive determinants.

Allergens↗

PubMed1978

[Estimation of allergenic potency of "Dermatophagoides pteronyssinus" by radioimmunoassay of antigenic extracts (author's transl)].

The allergenic potency of different extracts of Dermatophagoides pteronyssinus was evaoluated by in vitro methods based on the RAST-procedure (radioallergosorbent-test). Both the direct titration and the inhibition methods were performed and gave comparable results. The inhibition method was studied particularly because it presented various technical advantages, such as the use of a standard immunoadsorbent. The allergenic activity of different extracts of D. pteronyssinus were compared and the results demonstrated the value of this method for the routine estimations of biological activity in allergenic extracts and for control uses in allergen standardization.

Acari↗

PubMed1984

Studies on allergens of mammalian origin.

Cat and dog saliva and extracts obtained from cat and dog hair have been examined by high-performance liquid chromatography (HPLC) to identify the likely allergenic molecules. Separation of the materials by size exclusion HPLC showed that several components in the range of apparent molecular weight from 35,000 to 200,000 had inhibitory activity in the radioallergosorbent test (RAST) when tested against pooled serum from donors hypersensitive to dogs and cats. One of these components active in our test system was identified as albumin. Despite differences in gross composition of the extracts no significant difference in the position of the active fractions was observed between cat hair and saliva, between dog hair and saliva or between hair extracts from different breeds of dog. Fractionation by anion-exchange HPLC, although promising, was complicated by problems of sensitivity.

Allergens↗

PubMedDate not supplied

Latex allergy in spina bifida patients: prevalence and surgical implications.

We interviewed 93 consecutive children with spina bifida who were scheduled for operation to document (a) the prevalence of latex sensitivity, (b) predictors of anaphylactic reaction, and (c) the risk of type I hypersensitivity reaction perioperatively. Of these patients, 9.7% were clinically allergic. Radioallergosorbent testing (RAST) was 89% sensitive. All patients with known latex allergy were premedicated, and rigorous efforts were made to avoid latex exposure. No intraoperative anaphylactic reactions were noted. One postoperative reaction occurred in a history-positive, RAST-negative patient. We conclude that operation can be performed safely in patients with latex allergy.

Adolescent↗

PubMed1982

IgE screening in 1701 newborn infants and the development of atopic disease during infancy.

IgE screening was done using the Phadebas IgE PRIST technique on the cord blood of 1701 newborn infants. Of these 8.3% developed obvious or probable atopic disease, predominantly atopic dermatitis and bronchial asthma, during the first 18 months of life. Of infants with a family history of atopic disease 10.5% developed such illness; the corresponding figure for infants with an initially high IgE concentration was 70%. Atopic disease developed in 73% of infants with a high IgE concentration in cord blood and a family history, but in only 3% of infants with a low IgE and no family history. A high IgE concentration in cord blood was associated with a high IgE and a positive radioallergosorbent test at between ages 18 and 24 months more often than was a low initial IgE level, indicating that in man as in animals there are high and low IgE responders already genetically coded at birth. IgE screening in cord blood is recommended if there is obvious atopy in both parents or if severe atopic disease if present in a sibling or in one parent.

Fetal Blood↗

PubMed1988

Isolation and characterization of Poa p I allergens of Kentucky bluegrass pollen with a murine monoclonal anti-Lol p I antibody.

The Poa p I allergens were isolated from the retentate fraction of a dialyzed preparation of an aqueous extract of Kentucky bluegrass pollen by means of a reverse immunosorbent prepared with a murine anti-Lol p I monoclonal antibody, Mab 290-A-167. By sodium dodecyl sulphate-polyacrylamide gel electrophoresis and preparative isoelectrofocusing, Poa p I was found to consist of a 35.8-kD component with an isoelectric point of 6.4 and a 33-kD component with one of 9.1 and designated as Poa p Ia (acidic) and Poa p Ib (basic), respectively. The relative protein content of these components was estimated from the intensity of the stained bands following sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Thus, Poa p Ia appeared to be the major protein constituent, and on Western immunoblot it also bound the monoclonal antibody to a greater extent than Poa p Ib. On the other hand, Poa p Ib was shown by Western immunoblot and autoradiographic analysis, to bind to a greater extent the IgE antibodies present in a pool of sera from grass-allergic individuals. Therefore, Poa p Ib was considered as the major allergenic component of Poa p I. By competitive inhibition of the radioallergosorbent test, it was demonstrated that the Mab inhibited the binding of Poa p I allergens to human IgE antibodies to the extent of 70%. Hence, it is suggested that Mab and human IgE antibodies recognize identical or closely related determinants of Poa p I allergens.

Allergens↗