Localization of Der f 2 in the gut and fecal pellets of Dermatophagoides farinae

Background:  House dust mite derived materials are known to be the most potent agent inducing allergic diseases. Localization of Der f 2 was attempted to specify the sites and concentrations of Der f 2 within the mite, which may indicate the importance of secreted materials and nonexcreted body components as allergen sources. Methods:  Serial cryostat sections of embedded live mites and the fecal pellets, collected by brush, were immunoprobed using monoclonal antibody (mAb) 2F38 raised against recombinant (r) Der f 2. Results:  Highest concentrations were found in the anterior midgut, implying that this is the site of Der f 2 synthesis and secretion. Digestive material and defecated fecal pellets were also labeled with mAb. Conclusions: Our results show that the major allergen, Der f 2, found in the house dust miteD. farinae is derived from the digestive tract, and is concentrated in the feces.