Colonial Growth in Agar of Cells Derived From Adenovirus-Induced Hamster Tumors2

Abstract

Cells derived from adenovirus-induced hamster tumors grew as colonies in soft agar; normal hamster cells did not. Tumor cells induced by “hybrid” virus, i.e., adenovirus type 7 with simian virus 40, (SV40) and by type 12/SV40 “hybrid” virus formed larger colonies than did tumor cells induced by adenoviruses types 12 or 31 without the SV40 gene(s). When transplanted into hamsters, colonies of types 7/SV40 and 12/SV40 cells induced progressively growing tumors. The smaller colonies of types 12 and 31 cells tested in these experiments did not cause tumors in hamsters, however, and this might be due to the small number of cells in these colonies. The cytologic characteristics of the colonies of type 7/SV40 cells and the hamster tumors they induced were similar to those of SV40-induced tumors; colonies of type 12/SV40 cells and the hamster tumors they caused resembled adenovirus type 12-induced tumors. The colonies of type 7/SV40 cells and the hamster tumors induced by such colonies contained only SV40 tumor antigen; the colonies of type 12/SV40 cells and the tumors induced by such colonies contained tumor antigens to either type 12, SV40, or to both type 12 and SV40.