Oncogenic Transformation of Hamster Embryo Cells in vitro by Adenovirus Type 5

Abstract

JUDGED on the basis of virus inoculation tests in newborn hamsters¹, human adenovirus type 5 is considered to be non-oncogenic. The virus does transform rat embryo cells with low efficiency in vitro^2,3, although these cells do not form tumours in rats (my unpublished results). Infection of hamster cells in vitro with type 5 adenovirus gives rise to a productive infection (ref. 4 and my unpublished results) and most of the cells are killed. Because of this extensive cell killing transformation of hamster cells by adenovirus type 5—if it does occur—is unlikely to have been detected. To determine if adenovirus type 5 can transform permissive cells, hamster embryo fibro-blasts (HEF) were infected with temperature sensitive (ts) mutants⁵ at the restrictive temperature which prevents cell killing caused by virus replication. The mutants used transform non-permissive rat embryo cells at the restrictive temperature (my unpublished results) with frequencies similar to wild type virus, thus the viral function(s) involved in transformation of those cells are not affected by these particular ts mutations.