Generation of an immortal differentiated lung type-II epithelial cell line from the adult H-2KbtsA58 transgenic mouse

Summary This paper describes a new fully differentiated Type-II alveolar epithelial cell line designated T₇, derived from transgenic H-2K^b-tsA58 mice, capable of being passaged as an immortalized cloned cell line in culture. H-2K^b-tsA58 mice harbor a temperature-sensitive (ts) mutant of the simian virus 40 (SV40) large tumor antigen (T antigen) under the control of the γ-interferon (INF)-inducible mouse major histocompatibility complex H-2K^b promoter. When cultured under permissive conditions (33°C and in the presence of γ-INF) cells isolated from H-2K^b-tsA58 mice express the large T antigen, which drives the cells to proliferate. However, upon withdrawal of the γ-INF and transfer of the cells to a higher temperature (39°C), T antigen expression is turned off, the cells stop proliferating and differentiate. The T₇ cell line is a clonal cell line originally derived from a Type-II cell-rich fraction isolated from lungs of H-2K^b-tsA58 mice. The T₇ cells form confluent monolayers, and have a polarized epithelial cell morphology with tight junctions and apical microvilli. In addition, the T₇ cells have distinct cytoplasmic lamellar bodies, which become more numerous and pronounced when the cells are grown under nonpermissive conditions. The T₇ cells synthesize and secrete phosphatidylcholine and the three surfactant proteins, SP-A, SP-B, and SP-C. The T₇ cell line is unique in that it is the first non-tumor-derived Type-II cell line capable of synthesizing and secreting the major components of surfactant. Based on the criteria studied, the T₇ cell line is phenotypically very similar to normal Type-II cells. The T₇ cell line, therefore, should prove a valuable experimental system to advance the study of the cell biology/physiology of surfactant metabolism and secretion as well as serve as a model for other studies of Type-II cell physiology.