Adenovirus transformation of hamster embryo cells.

Inoculation of hamster embryo cell cultures with human adenovirus type 12 (Ad12) or simian adenovirus (SA7) resulted in the formation of foci of morphologically transformed cells within 12 days. The rapid appearance of well-defined foci was dependent upon the transfer of cells into new plates, with sufficient dilution after virus adsorption, and was independent of virus dose. Dose-response studies showed linearity of focus formation with dilution of Ad12 or SA7. Results averaged from several experiments show plaque-forming unit to focus-forming unit ratios of approximately 1.8 x 10(6) for Ad12 and 2.6 x 10(5) for SA7. Other experiments showed that most of the adenovirus involved in transformation was adsorbed by 3 hr. Cell lines derived from SA7 transformed cells produced tumors within 19 days when inoculated intradermally into young adult hamsters. Such cell-induced tumors histologically resembled SA7 virus-induced hamster tumors. Formation of tumors with SA7 transformed cells was inhibited by prior immunization of test animals with SA7 or Ad12 virus.