Standardization of radioallergosorbent test (RAST) and allergen extracts in terms of the WHO standard for IgE.
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Allergens↗
Biomedical subjects
K G Huggins
Publications and source records attributed to K G Huggins.
An anomalous effect of allergen concentration on weal size elicited by skin testing for immediate hypersensitivity.
We report the finding of anomalous responses in the skin of atopic individuals when prick tested with serial dilutions of cocksfoot grass pollen extracts. Each pollen extract was standardized using RAST inhibition activity related to the WHO standard for IgE. 75% of the patients gave a larger weal area with an allergen concentration of 1:10(5) than with the next higher concentration, i.e. 1:10(4). Possible mechanisms whereby a larger skin weal is elicited with a lower concentration of allergen are discussed. This is not a rare finding and can be observed in patients undergoing routine skin testing in the clinic, even where extracts are diluted over a relatively narrow concentration range.
Allergens↗
Standardization of radioallergosorbent test (RAST) and allergen extracts in terms of the WHO standard for IgE.
An 131I-labelled IgE myeloma, standardized against the WHO reference serum for IgE was bound in varying concentrations to discs bearing anti-human light chain. These were used to construct a calibration curve for the subsequent binding of 125I-labelled anti-IgE, thus relating 125I counts to WHO IgE units. The calibrated anti-IgE could then be used to measure the actual amount of specific IgE bound to an allergen disc in the radioallergosorbent test. Using this standardized system, soluble allergen extracts could then be assayed by their ability to inhibit the binding of a defined amount of specific IgE, thereby enabling their activity to be expressed in WHO IgE units.
Allergens↗
Effect of allergenic structure on IgE levels in rats and mice.
In outbred Lister hooded rats and inbred BALB/c mice, the IgE antibody response to CE induced in the presence of aluminum hydroxide adjuvant, is more difficult to suppress with high doses of antigen and/or frequent administration of antigen, than are such responses to DNP4.3-OA. Both types of IgE antibody were assayed by PCA in rats challenged with 1 mg of CE or DNP26-BSA. Unlike the rat system, anti-CE IgE responses could be induced in the BALB/c mouse in the absence of adjuvant. After a long course of weekly injections the IgE titer was the same (1 in 160) in all groups of mice given 6 ng to 630 micrograms/injection. The threshold sensitivity to CE of PCA induced by 1 in 5 dilutions of these sera ranged from 0.3 micrograms for sera from mice immunized with 6 ng per injection up to 10 micrograms for sera from mice immunized with 630 micrograms per injection. Only a small part of this difference in sensitivity could be accounted for by the presence of blocking antibody.
Allergens↗
Skin-test anomaly.
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Dose-Response Relationship, Immunologic↗
Letter: Local IgE antibodies in allergic rhinitis.
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Arachnida↗
Local production of specific IgE antibodies in allergic-rhinitis patients with negative skin tests.
A group of patients with allergic rhinitis had a clinical history strongly suggestive of house-dust-mite (Dermatophagoides pteronyssinus) allergy but negative skin reactions when prick tested with D. pteronyssinus extracts. These patients were proved to be clinically allergic by nasal provocation with this allergen. Although radioallergosorbent tests showed that these patients lacked specific IgE antibodies in their serum, they did have specific antibodies in their nasal secretions. These findings indicate that these patients had allergic rhinitis mediated by the local production of IgE antibodies.
Adolescent↗