Mediator release assay for assessment of biological potency of German cockroach allergen extracts - 15/08/11
, Ramon Bencharitiwong, BS a, John Schwarz, PhD, MHSc b, Gloria David, PhD, MHSc b, Peyton Eggleston, MD c, Peter J. Gergen, MD, MPH d, Andrew H. Liu, MD e, Jacqueline A. Pongracic, MD f, Sampson Sarpong, MD g, Hugh A. Sampson, MD a
Reprint requests: Anna Nowak-Wegrzyn, MD, Mount Sinai School of Medicine, Department of Pediatrics, Box 1198, One Gustave L. Levy Place, New York, NY 10029.Abstract |
Background |
Cockroach is an important allergen in inner-city asthma. The diagnosis and treatment of cockroach allergy has been impeded by the lack of standardized cockroach extracts.
Objective |
We investigated the utility of a mediator release assay based on rat basophil leukemia (RBL) cells for comparing the potency of German cockroach extracts.
Methods |
RBL cells (line 2H3) transfected with human FcεRI were passively sensitized with sera from subjects with cockroach allergy and stimulated with serial dilutions of 3 commercial cockroach extracts (1:10 weight/volume). In addition, the in-house prepared extract was tested in separate experiments with pooled sera that produced optimal performance in the RBL assay. N-hexosaminidase release (NHR) was used as a marker of RBL cell degranulation and was examined in relation to the intradermal skin test (ID50EAL) and serum cockroach-specific and total IgE levels.
Results |
The median cockroach-specific IgE concentration in 60 subjects was 0.72 kUA/L (interquartile range, 0.35-2.97 kUA/L); 19 sera (responders) produced a minimum 10% NHR to more than 1 extract. Responders had higher median cockroach-specific IgE (7.4 vs 1.0 kUA/L) and total IgE (429 vs 300 kU/L) levels than nonresponders. Ranking of extract potency was consistent between the mediator release assay and the ID50EAL. For the in-house prepared cockroach extract, the dose-response curves were shifted according to the concentration of the extract. NHR was reproducible between different experiments by using pooled sera.
Conclusion |
The mediator release assay measures biologic potency and correlates with the ID50EAL. It should be further evaluated to determine whether it could be used to replace intradermal skin test titration for assessing the potency of cockroach extract.
Le texte complet de cet article est disponible en PDF.Key words : Cockroach, cockroach allergy, cockroach extract, rat basophil leukemia cells, passive sensitization, mediator release, mediator release assay, extract potency, ID50EAL, biologic potency, cockroach extract standardization
Abbreviations used : ED50, ID50EAL, NHR, RBL
Plan
| Supported in whole or in part by federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, under contract nos. N01-AI-25496 and NO1-AI-25482. A. Nowak-Wegrzyn is supported in part by NIH NIAID AI 059318. |
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| Disclosure of potential conflict of interest: A. H. Nowak-Wegrzyn is a Safety Board Member for Schering-Plough, has received research support from Novartis Vaccines, and is President Elect of the New York Allergy and Asthma Society. J. A. Pongracic has received research support from the University of Wisconsin/National Institute of Allergy and Infectious Diseases, Novartis, and the Food Allergy Project. H. A. Sampson is a consultant and shareholder of Allertein Pharmaceuticals, LLC; is on the advisory board for Schering-Plough; has received research support from the Food Allergy Initiative, the National Institute of Allergy and Infectious Diseases, and the National Institutes of Health; is a consultant/scientific advisor for the Food Allergy Initiative; and is President of the American Academy of Allergy, Asthma & Immunology. The rest of the authors have declared that they have no conflict of interest. |
Vol 123 - N° 4
P. 949 - avril 2009 Retour au numéro
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