ISOLATION AND CHARACTERIZATION OF BASAL CELLS FROM HUMAN UPPER RESPIRATORY EPITHELIUM

Cellular pathways of normal and reparative differentiation of upper ai rway epithelium are not well understood. Of the three main cell types, basal and secretory cells are known to divide, while ciliated cells a re considered terminally differentiated. Several investigations suppor t the role of the basal cell as a progenitor cell type, but others sug gest that the secretory cell can regenerate a complete mucocilliary ep ithelium. Thus, lineage relationships within renewing adult epithelia are still unclear. Understanding the pathways involved in upper airway epithelial cell differentiation is critical for studying injury and r epair mechanisms and for developing clinical strategies for tracheal r econstruction. We undertook the current studies to determine the integ rin profile of isolated human upper airway basal cells. Respiratory ep ithelial cells (REC) were isolated by elastase digestion, stained with FITC-labeled Griffonia simplicifolia isolectin B-4 (GSI-B-4), and sor ted by flow cytometry. Approximately 80% of the lectin-positive cells were basal cells, as determined by morphology and cytokeratin staining . These cells expressed integrins alpha(1), alpha(2), alpha(3), alpha( 5), alpha(v) beta(5), beta(1), beta 3, and alpha(6) beta(4), by immuno histochemistry. This is the first report to identify the integrin prof ile of isolated human upper airway basal cells. These basal cells coul d be maintained on type I collagen for at least 7 days, where they bec ame partially confluent and retained expression of cytokeratins 5 and 14. Availability of pure populations of basal cells should permit inve stigations of their role in both normal and maladaptive repair of adul t upper airway epithelium. (C) 1997 Academic Press.