Evaluating Antigen-Specific IgE Using the Rat Basophil Leukemia Cell (RBL) Assay

Allergic diseases (atopy) include asthma, allergic rhinitis, conjunctivitis, and allergic sinusitis. It is estimated that up to 90% of asthmatics are atopic and have an allergy trigger for asthmatic episodes. In order to assess the risk of allergy induction associated with inhalation exposure, animal models of protein allergy have been developed. These models have been used both to identify proteins as allergens and to assess their relative potency. Often these research situations include allergens that are not well characterized or are unknown. In these situations, specific allergens are not available to be evaluated by more well-known assays (such as ELISAs), and developing a specific assay to evaluate an extract or mixture for an unknown or potential allergen is very time consuming and generally requires purified antigen/allergen. Additionally, when the comparison of the relative potency of multiple extracts is of interest, a common/generic platform is necessary. A more generic method, the rat basophil leukemia cell assay (RBL assay), has been developed which provides insight into the allergenicity of extracts and mixtures as well as providing a common platform for relative potency comparison between/among these complex allergen sources.