USE OF MUCIN ANTIBODIES AND CDNA PROBES TO QUANTIFY HYPERSECRETION IN-VIVO IN HUMAN AIRWAYS

Mucus hypersecretion is a prominent feature of the airway's response t o injury, The ability to quantitatively detect mucin and mucin mRNA in vivo in human airways would facilitate the determination of safe expo sure levels to various air pollutants and the identification of drugs capable of attenuating mucus hypersecretion. To this end, we have deve loped two assays: an enzyme-linked immunosorbent assay (ELISA) quantif ying mucin-like molecules and a polymerase chain reaction (PCR)-based assay quantifying mucin mRNA. These tests are performed on bronchial l avage fluid and epithelial cells brushed from the surfaces of human ai rways at bronchoscopy. The PCR data are normalized to eliminate potent ially confounding effects of nonepithelial cells in the samples. In a study of six smokers and six nonsmokers, the ELISA detected significan tly more mucin-like material in the airways of the smokers than of the nonsmokers. The median mucin concentration for the smokers was 52.2 m ug/ml (range, 16.3 to 4,860.0), whereas that for the nonsmokers was 12 .7 mug/ml (range, 4.5 to 22.9). The difference between smokers and non smokers was statistically significant (P less-than-or-equal-to 0.01). The PCR-based test showed a trend for RNA samples from smokers to be e nriched (vis-a-vis nonsmokers) in mucin mRNA.