IMMUNE-REACTIVITY OF RECOMBINANT ISOFORMS OF THE MAJOR HOUSE-DUST MITE ALLERGEN DER-P-2

Background Recombinant Der p 2, expressed in yeast, lacked reactivity with 5 monoclonal antibodies against natural Der p 2. Objective The ai m of this study was to investigate whether the lack of reactivity with recombinant Der p 2 can be explained by the existence of isoforms. Me thods By site-directed mutagenesis three recombinant isoforms of Der p 2 were produced. Reactivity with monoclonal antibodies and human IgE was analysed by means of RAST and RAST-inhibition. Results All five mo noclonals that lacked reactivity with the originally selected isoform, showed reactivity upon replacement of aspartic acid by asparagine at position 114. The other two substitutions (at position 26 and 47) had no effect. Binding of human IgE (n = 10) was not significantly influen ced by the isogenetic variation at position 114. Conclusions Monoclona l antibodies raised against natural Der p 2 can sometimes discriminate between different isoforms, allowing the study of the natural occurre nce of isoforms. For application in allergen-measurement assays, non-d iscriminating monoclonal antibodies should be selected.