Regulation of airway secretory cells.

Inhaled particles are cleared from the airways by ciliary transport of a discontinuous mucous layer. The effectiveness of this process depends on the viscoelastic properties of the secretion, which in turn depend on the composition and interaction of the glycoprotein constituents. In human airways, two major cell types in the surface epithelium (goblet and ciliated) and two in the submucosal glands (serous and mucous) are known to contain mucin- and/or serum-type glycoproteins. This article summarizes current knowledge regarding the secretable products of each of these cell types and the conditions under which they are released into the airway lumen.