Mediator release assay for assessment of biological potency of German cockroach allergen extracts

Anna H. Nowak-Wegrzyn*, Ramon Bencharitiwong, John Schwarz, Gloria David, Peyton Eggleston, Peter J. Gergen, Andrew H. Liu, Jacqueline A. Pongracic, Sampson Sarpong, Hugh A. Sampson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

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 Fcε{lunate}RI 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.

Original languageEnglish (US)
Pages (from-to)949-955.e1
JournalJournal of Allergy and Clinical Immunology
Volume123
Issue number4
DOIs
StatePublished - Apr 2009

Keywords

  • Cockroach
  • IDEAL
  • biologic potency
  • cockroach allergy
  • cockroach extract
  • cockroach extract standardization
  • extract potency
  • mediator release
  • mediator release assay
  • passive sensitization
  • rat basophil leukemia cells

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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