Human IgE Monoclonal Antibodies to Inhaled and Food Allergens: Unique Probes for Clinical Investigation.

Abstract

Investigation of immediate hypersensitivity has been hampered by the limitations of using polyclonal IgE ab, present at low concentrations in allergic sera. Our goal was to isolate human monoclonal IgE antibodies (mAb) to specific allergens as they occur in vivo, to evaluate their allergen specificity, potency and binding activity. Human IgE mAb (n=20) were obtained by electrical cytofusion of cultured human B cells from peripheral blood of allergic patients. IgE mAb were quantified by ImmunoCAP and analyzed by SDS-PAGE. IgE mAb dose response curves to major inhalant and food allergens (e.g. Der p 1, Fel d 1, Ara h 2, Gal d 2) were compared by ELISA. IgE mAb were produced in mg amounts (1mg IgE is ∼416,000 IU) and targeted major inhaled allergens (e.g. mite, dog, and cat) and foods (peanut, cashew, walnut, milk, and egg). IgE mAb directed against different epitopes were obtained (e.g. to Der p 2). ELISA dose response curves were sigmoidal with limits of detection of <1ng/ml, indicating the IgE mAb had high affinity. Natural human IgE mAb to a diverse panel of clinically important allergens are unique probes for allergen identification, quantification of IgE antibody responses, epitope analysis and mast cell and basophil activation assays. Human IgE mAb used as calibrators will improve in vitro allergy molecular diagnostics and reduce dependence on allergic sera. They will also enable mechanistic studies of IgE mediated allergic reactions.