Immortalization of rat middle ear epithelial cells by adeno 12-SV40 hybrid virus

Rat middle ear epithelial cells were infected with the adeno 12-SV40 hybrid virus. The cell line thus obtained displays features of primary cultured epithelial cells in both light microscopic and ultrastructural examinations. The immortalized cells have been in continuous proliferation for 40 passages and more than 17 months. Immunohistochemical analysis of the immortalized cells was positive for the SV40 T antigen and the tumor suppressor protein p53. The cells also stained positive for cytokeratin, an epithelial cell marker, and negative for vimentin, a fibroblast marker. These results, together with karyotype analysis, indicate that this cell line originated from rat middle ear epithelial cells and retains the characteristics of epithelial cells. This cell line will be useful for studying the normal cellular biology of middle ear epithelial cells, as well as the cellular and molecular mechanisms involved in the bacteria-middle ear epithelial cell interaction.