Use of a monoclonal antibody enzyme-linked immunosorbent assay to measure human respiratory glycoprotein production in vitro

High-molecular-weight glycoprotein from human airway cultures was used to generate murine monoclonal antibodies, one of which recognizes a high-molecular-weight, hyaluronidase-resistant glycoprotein localized by immunofluorescent microscopy and immunogold electron microscopy to the secretory granules of human airway submucosal gland mucous cells and goblet cells. This monoclonal antibody was used to develop an enzyme-linked immunosorbent assay (ELISA) that was adapted to the study of respiratory glycoprotein secretion from human airways in vitro. Using the assay, the effect of a known mucus secretagogue, the cholinergic agonist methacholine, was studied on explant cultures of tissue from human bronchus or from human nasal mucosa. In studies of human bronchus explants, methacholine, 100 and 10 microM, stimulated increased secretion of respiratory glycoprotein (RGP) by 109 +/- 8% (n = 14; P less than 0.001) and 96 +/- 14% (n = 9; P less than 0.001), respectively, above control values. In studies of human nasal turbinate mucosal explants, methacholine, 100 and 10 microM, stimulated increased secretion of RGP by 75 +/- 28% (n = 7; P less than 0.01) and 70 +/- 21% (n = 4; P less than 0.01) above control values. An ELISA for the measurement of RGP secretion may provide a sensitive and more specific method for the performance of in vitro studies of RGP secretion from human tissues.