Mediator release assays based on human or murine immunoglobulin E in allergen standardization
Article first published online: 28 NOV 2006
Clinical & Experimental Allergy
Volume 37, Issue 1, pages 141–150, January 2007
How to Cite
Kaul, S., Lüttkopf, D., Kastner, B., Vogel, L., Höltz, G., Vieths, S. and Hoffmann, A. (2007), Mediator release assays based on human or murine immunoglobulin E in allergen standardization. Clinical & Experimental Allergy, 37: 141–150. doi: 10.1111/j.1365-2222.2006.02618.x
- Issue published online: 28 NOV 2006
- Article first published online: 28 NOV 2006
- Submitted 20 January 2006; revised 10 August 2006; accepted 19 September 2006
- allergen extract;
- biological activity;
- humanized rat basophilic leukaemia cells;
- mediator release;
- rat basophilic leukaemia cells;
Background The biological potency of allergens can be measured by provoking mediator release from effector cells. As established immunochemical methods in allergen standardization only determine inhibition potency or major allergen content, routine tests for biological potency may enhance standardization and batch control of allergen products.
Objective The general performance and application potential of biological in vitro assays in batch control and standardization of allergens and as a tool for verifying activity and stability of allergen standards were analysed.
Methods Allergen extracts of five clinically relevant allergens from three to five different manufacturers were investigated. A CAP-IgE-inhibition assay was compared with mediator release assay (MRA)s based on murine or human basophils. Rat basophilic leukaemia (RBL) cells were passively sensitized with pooled murine allergen-specific IgE-containing sera. Humanized RBL cells and human-stripped basophils were sensitized with pooled patient's sera, which were also used for the CAP-IgE-inhibition assay. Allergen specificity of the sera was determined by immunoblotting.
Results A good batch-to-batch consistency was found with each assay among all manufacturers and allergens tested. Between different manufacturers, the products showed differences in activity and the various assays indicated an almost identical ranking. However, the biological assays revealed qualitative differences of biological activity or composition of allergen preparations undetectable by IgE-inhibition assay.
Conclusions MRAs provide refined information on allergen activity, either confirming the results of IgE-inhibition assay, or indicating differences requiring further investigation, and represent a highly sensitive novel tool in allergen standardization. By using permanently cultivated cell lines, repeated venepuncture to obtain human basophils is avoided. As in the RBL assay, the coefficient of variation for the release values were below 15% and for the ED50 below 25%, the assay is suitable to determine differences that are relevant for batch control purposes.