Isoelectrophoretic patterns of Der p 2 isoforms in house dust from different homes

Relative environmental exposures to different allergen isoforms are unknown. We aimed to determine the prevalence of different isoforms of the mite allergen Dermatophagoides pteronyssinus Der p 2 in house dust from different homes. Mattress reservoir dust from 10 different homes was extracted. Eluates were concentrated by spin-filtration, separated by polyacrylamide gel (PAGE) isoelectric focusing and immunoblotted. Der p 2 isoforms were detected by the monoclonal antibody alphaDpX and a chemiluminescence-based reporter system. Radiographs were scanned, analyzed by standard densitometry software and the number and relative motilities of bands were compared between samples. Band molecular mass was estimated by PAGE. Recombinant isoforms rDer p 2.0101, rDer p 2.0102 and rDer p 2.0103 were used as standards, run on PAGE-isoelectric focusing and then analyzed by denaturing gel isoelectric focusing. Isoelectric focusing and immunoblotting: Multiple bands were detectable in house dust samples (range 3-8 bands). Relative band motility was similar; up to 5 different bands were common to samples from different homes. Native gel electrophoresis: Der p 2 had a tendency to form dimers and trimers. Denaturing gel electrophoresis of Der p 2 recombinant isoforms: Each isoform demonstrated a tendency to form 2 or 3 bands which could not easily be resolved under stringent conditions (6M urea). Polyacrylamide gel isoelectric focusing indicates the presence of multiple Der p 2 isoforms in dust extracts. Some of the observed bands may represent multimeric complexes of Der p 2. Future studies to determine environmental exposure to different isoforms should take this into account.