Monoclonal antibodies against Der s 1, a major allergen of Dermatophagoides siboney.

Six stable clones secreting murine monoclonal antibodies (Mabs) against Der s 1 were obtained. The binding of Mabs showed cross-reactivity with Dermatophagoides farinae, as determined by enzyme-linked immunosorbent assay (ELISA). In a Western blot assay, antibodies reacted with a 24-kD protein considered to represent the major allergen Der s 1. The repertoire of antigenic sites on Der s 1 was studied using a panel of Mabs. Epitope specificity of the Mabs was determined by both competitive inhibition and sandwich ELISA assays. The results defined six different, non-overlapping and non-repeated antigenic sites on the allergen molecule. Der s 1 allergen from Dermatophagoides siboney extracts was purified by Mab affinity chromatography, this procedure gave 43% recovery of >90% pure allergen. The purified allergen had capacity to bind specific human IgE and demonstrated an allergenic activity of up to 77% of total D. siboney extract. An Mab-ELISA was developed using Mabs directed against different epitopes on Der s 1. This assay could detect up to 1 ng/ml of Der s 1 and Der f 1 in allergen preparations. Copyright 2000 S. Karger AG, Basel