Cloning and characterization of a new allergen, Mag 3, from the house dust mite, Dermatophagoides farinae: Cross-reactivity with high-molecular-weight allergen

Abstract A new immunoreactive clone whose sequence is not homologous to that of any of the previously identified mite allergens was isolated by successive immunoscreening of a Dermatophagoides farinae cDNA library with rabbit antisera to an extract of the house dust mite and IgE in pooled sera from patients allergic to mites. Rabbit antibodies specific for the recombinant protein recognized a 177 kD protein in a mite body extract. This immunoreactive protein was located in the circumferential tissues of esophagus, gut and the other internal organs in mites. The reaction of human IgE to the purified natural antigen was inhibited competitively to 30% by the recombinant antigen. In terms of the frequency and the intensity of response to specific IgE in sera from asthmatic patients, the natural protein was similar to Der f 2, while the recombinant protein was slightly less allergenic by these criteria. We conclude that the natural protein from the house dust mite, D. farinae , is an important allergen.