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Updated: Oct 3, 2026
Absorption of Nasal and Bronchial Fluids: Precision Sampling of the Human Respiratory Mucosa and Laboratory Processing of Samples
Published on: January 21, 2018
[Protease inhibitory activities of nasal secretion on house dust mite allergen]
Objective:
To elucidate the interaction of protease inhibitors and house dust mite allergen in vitro.
Methods:
Nasal secretion was collected by suction from patients with house dust mite nasal allergy, diluted immediately with PBS pH 7.0, mixed with vortex for 10 minutes, and then centrifuged at 2,000 g for 10 minutes. The supernatant was kept at -80 degrees C for use. Synthetic low molecular weight fluorogenic peptide substrates were applied to evaluate protease activities. Crude mite extract and other proteases were used, each of them was preincubated in the presence or absence of nasal fluid or other protease inhibitors at 37 degrees C for 30 minutes. The intensity of fluorescence of aminomethylcoumarin released from the cleaved substrate was measured.
Results:
Nasal fluid exhibited mild trypsin-like and other protease activities. It inhibited the activities of trypsin and trypsin-like serine proteases and papain-like cysteine proteases in crude mite extract in a dose-dependent manner.
Conclusions:
Nasal fluid possibly plays a role in inhibiting penetration of allergen into the nasal mucosa by producing protease inhibitor-protease complex in the nasal mucus layer of patients with mite allergy.
Insights
Nasal fluid contains protease inhibitors that reduce house dust mite allergen activity. This suggests a protective role for nasal mucus in mite allergy by forming inhibitor-protease complexes.
Area of Science:
- Immunology
- Biochemistry
Context:
- House dust mite (HDM) allergy is a prevalent condition.
- Proteases from HDM are implicated in allergic inflammation and airway remodeling.
- The role of endogenous protease inhibitors in nasal secretions during HDM allergy is not fully understood.
Purpose:
- To investigate the in vitro interaction between protease inhibitors in nasal secretions and HDM allergens.
- To characterize the protease activities present in nasal fluid from patients with HDM allergy.
- To assess the inhibitory effects of nasal fluid on HDM-derived proteases.
Summary:
- Nasal secretions from patients with HDM allergy were analyzed for protease activity and inhibitory capacity.
- The study found that nasal fluid possesses mild trypsin-like and other protease activities.
- Importantly, nasal fluid demonstrated a dose-dependent inhibition of trypsin-like serine proteases and papain-like cysteine proteases found in crude HDM extract.
Impact:
- Nasal fluid protease inhibitors may limit allergen penetration into the nasal mucosa.
- The formation of protease inhibitor-protease complexes in nasal mucus could be a key defense mechanism.
- Findings contribute to understanding the innate immune response in allergic rhinitis.
