Human tracheobronchial submucosal gland cells in culture

Cellular mechanisms regulating airway secretion, secretory products of individual airway cell types, and control of airway cell growth and differentiation are poorly understood. In order to aid studies of these questions, we have established a system for culturing human tracheobronchial submucosal gland cells. Gland acini were isolated by enzymatic disaggregation from submucosal tissue obtained postmortem from patients without pulmonary diseases and from patients with cystic fibrosis. In culture, acini attached to a collagen substratum, and gland cells proliferated and formed confluent monolayers which were homogeneous by phase microscopy. In contrast to cells of freshly disaggregated acini which expressed either serous or mucous gland cell secretory antigens, in culture virtually all cells (greater than or equal to 95%) concurrently expressed both antigens as assessed by immunocytochemical staining with serous and mucous cell-specific antibodies. Similarly, electron microscopy revealed cells with serous- or mucous-type secretory granules, and cells containing both types of granules. Cultures incorporated 35S into high (greater than 10(6) D) and lower (greater than 700 kD; 150 kD) molecular weight molecules. Cholinergic and adrenergic agonists increased release of radio-labeled secretions. These findings demonstrate that human tracheal gland cells in culture retain immunocytochemical, ultrastructural, and functional features of both differentiated serous and mucous gland cells. This culture system will be useful for studying the biology and pathology of human tracheobronchial submucosal gland cells.