Respiratory mucous glycoproteins (MGP) are produced by at least three cell types in the respiratory tract. These glycoproteins are relatively heterogeneous in size; however, no specific characteristics are available for MGP secreted by different cells. Therefore, quantitation of MGP secreted by different cells has not been possible. Current work is directed toward the development of murine monoclonal antibodies that recognize specific secretory products of human submucosal gland mucus and serous cells and human epithelial goblet cells. Such antibodies will allow for the development of ELISA assays for specific secretory products and for the separation by affinity chromatography of MGP of a specific cell of origin.