Analysis of alveolar epithelial cell phenotypes in culture. Primary rat alveolar epithelial type II cells were isolated and cultured on glass coverslips alone or coverslips precoated with Matrigel (day 2 only) for either 2, 3, 5 or 7 days. Immunofluorescence was then performed using antibodies specific to the ATII markers, SP-B and LB180, as well as the ATI markers T1α and AQP-5. The rat cell line, R3/1, was also analyzed. Staining for the fibroblast marker, vimentin, was used to verify purity of the cultures.