Airway glycoprotein secretion parallels production and predicts airway obstruction in pulmonary allergy.

BACKGROUND: Airway obstruction, perhaps the most relevant clinical feature of asthma, is typically assessed in allergic asthma models as airway hyperresponsiveness. Excess secretion of airway glycoproteins also contributes to airway obstruction in asthma but is not measured as part of most experimental models.
OBJECTIVE: The purposes of this study were to develop a reliable, quantitative assay for detecting secreted airway glycoproteins and to assess the secretion of airway glycoproteins in comparison with other markers of airway obstruction resulting from allergic lung inflammation.
METHODS: Two microtiter plate-based glycoprotein-detecting methods were developed, one using an antiglycoprotein antibody and the other using the glycoprotein-binding plant lectin, jacalin. Both methods were used to assess airway glycoprotein secretion in response to 2 defined agonists given intranasally, IL-13 and an allergen derived from Aspergillus fumigatus. Glycoprotein secretion was assessed concomitant with another measure of airway obstruction, airway hyperresponsiveness provoked by acetylcholine challenge, and a histologic method for quantitating glycoprotein production.
RESULTS: Both assays were sufficient for quantitating airway glycoproteins over the full range of values encountered from murine bronchoalveolar lavage and yielded highly reproducible data. Secretion of airway glycoproteins increased commensurate with the detection of both airway hyperresponsiveness and airway glycoprotein production induced by IL-13 and allergen.
CONCLUSION: Airway glycoprotein secretion is a consistent feature of the allergic lung phenotype and likely contributes to airway obstruction induced by allergen in both humans and rodents.