Detection of at least one high-molecular-mass, IgE-binding component of the dust mite Lepidoglyphus destructor

We studied the allergen composition in an extract of the storage mite Lepidoglyphus destructor. Monoclonal antibodies (mAbs) were raised against L. destructor by a standard hybridoma technique. In the subsequent screening, we concentrated on mAbs fulfilling three criteria. First, in ELISA, mAbs were assessed against a panel of various mite species, and only those reacting exclusively with L. destructor extract were selected for further analyses. Secondly, mAbs were selected in immunoblotting according to whether or not a novel pattern of reactivity emerged in comparison with earlier results. Thirdly, by radioimmunoassay (RIA), we selected mAbs that recognized components which were also recognized by human IgE from sera RAST positive to L. destructor. This yielded an L. destructor-specific mAb (117F9) reacting with two previously unknown components of approximately 79 and 93 kDa, respectively. We also analyzed 80 sera for the presence of IgE binding to these components. These sera were divided into three groups according to their RAST specificity. Eighteen of the 30 sera (60%) that were RAST positive to L. destructor were also positive in RIA. Correlation was moderate between kU/l for L. destructor and the counts per minute values for the two components in RIA. The group of control sera lacking IgE antibodies against L. destructor displayed no positive results in RIA. However, 4/20 sera RAST positive to Dermatophagoides pteronyssinus but negative to L. destructor were scored as positive in RIA. We conclude that at least one of the high-mol.-mass components of L. destructor causes IgE-mediated sensitization.