Transformation of Rodent Cells by Adenovirus 19 and Other Group D Adenoviruses

Primary rat-embryo cells and NIL-2 hamster cells were transformed by adenovirus (Ad) types 9, 10, 13, 15, 17, 19, and 26. The transformed cells formed multilayered foci in monolayer cultures. Cell lines derived from such foci formed colonies when suspended in soft agar medium. Approximately 2.7 × 104 plaque-forming units (PFU) of Ad-19 were required to induce one focus of transformed rat cells. The highest transformation rates obtained were 0.01% for rat cells exposed to about 14 PFU/cell. In hamsters, Ad-19 and Ad-26 transformed NIL-2 cells formed tumors with the morphological characteristics of adenovirus tumors. Histologically, cell colonies of Ad-19 transformed cells also resembled adenovirus tumors. Complement fixation tests using sera from hamsters bearing tumors induced by Ad-19 or Ad-26 transformed NIL-2 cells indicate that the transformed cells shared a common T antigen with all members of adenovirus hemagglutination group 2 as well as types 20, 25, and 28. No virus-specific RNA could be detected in Ad-19 transformed rat or NIL-2 cells or in hamster tumors induced by Ad-19 cells. These data outline a fourth subgroup of human adenoviruses which share the ability to transform rat and hamster cells and which produce a common T antigen.