Contribution of cysteine and serine proteases to proteolytic digestion in an allergy-eliciting house dust mite

The digestive physiology of house dust mites (HDM) is interest to understand their allergenicity towards humans since many allergens are enzymes and/or excreted into airborne fecal pellets. aim this study provide insight on the biochemical basis proteolytic digestion in Dermatophagoides pteronyssinus, most widespread HDM species. First, assays using non-specific protein substrates purified and body extracts determined that body-associated activity almost exclusively dependent cysteine proteases, specifically major allergen Der p 1. By contrast, serine proteases contributed similarly estimated extracts. Second, screening group-specific peptide-based protease inhibitors followed by ingestion bioassays revealed human skin-derived inhibitor cystatin A produces a significant reduction mite feeding (i.e. guanine), triggers overproduction 1 (3-fold increase ELISA). Noteworthy, inhibition also resulted three non-target activities. Further incubation these with exogenous 1, but not other commercial restored trypsin (Der 3) chymotrypsin 6) activities, indicating responsible for activation vivo. Finally, role mite's discussed based remarkable autocoprophagic behavior reported study.