RODENT TRACHEAL EPITHELIAL-CELLS IN-VITRO - A COMPARATIVE-STUDY OF NORMAL-CELLS, ENHANCED GROWTH VARIANTS, SV40-TRANSFORMED CELLS AND THEIRINTERACTIONS

Tracheal epithelial cells of the golden Syrian hamster can be successf ully cultivated in vitro and applied as a model system of respiratory tract epithelium. By morphology and growth characteristics of tracheal epithelial cells, ''normal cells'', ''enhanced growth variants'' and ''transformed cells'' were distinguished in vitro. Hamster tracheal ep ithelial cells, transformed by Simian virus (SV)-40 expressed in cell nuclei the specific tumor (T-) antigen and showed an accumulation of t umor suppressor protein p53 by immunofluorescence. Cocultivation of '' enhanced growth variants'' and of ''transformed cells'' on a 'feeder l ayer'' of normal hamster tracheal epithelial cells revealed remarkable differences in loss of ''contact inhibition of growth''. A ''cytokine '' released by NIH-3T3 cells stimulated cell proliferation and seems t o be important for cell growth of hamster tracheal epithelial cells. P reliminary characterization of the ''cytokine'' disclosed a molecular weight of more than 30 kDa, a relative thermostability and a loss of a ctivity by treatment with mercaptoethanol indicating disulfide bridges in a molecule.