Induction experiments with adenovirus and polyoma virus transformed cell lines

Viral DNA sequences and gene products in hamster cells transformed by adenovirus type 2

Complementary strand-specific adenovirus DNA of full length or from endonuclease BamHI fragments was used as a probe to estimate the fractional representation and abundance of viral sequences in five hamster cell lines (Ad2HE1-5) transformed with UV-inactivated adenovirus type 2. The fraction of the viral genome present in the five transformed cell lines varied from 44% in the Ad2HE5 cell line to 84% in the Ad2HE3 cell line. The number of viral DNA copies per diploid cell equivalent ranged from 1.8 in the Ad2HE1 line to 7.1 in the Ad2HE4 line. In vivo labeling with [35S]methionine followed by immunoprecipitation with an antiserum against adenovirus type 2 early proteins revealed virus-specific polypeptides with molecular weights of 42,000 to 58,000 in extracts from all five hamster cell lines. Several other early viral polypeptides were detected in some of the adenovirus type 2-transformed hamster cell lines.

Murine tumor induction by cytomegalovirus

Cytomegalic inclusion disease can be induced in mice with relative ease. In the study reported here, grandular neoplasms were produced in four mice by means of immunosupression together with large doses of cytomegalovirus. The results of this study suggest that cytomegalovirus may well be an etiologic agent in the formation of salivary gland tumors.