The nature of tumor antigen of adenovirus type 12 and its formation in cultured cells after infection.

Tumor antigen in hamster tumors induced by adenovirus type 12 could be assorted by the complement-fixation test into two antigens : TS antigen, nonprecipitable by ultracentrifugation, and TP antigen, precipitable by ultracentrifugation. Tumor antigen was formed prior to the formation of infectious mature virus, viral coat protein, viral DNA or viral antigens in the lytic infection of human embryonic kidney cell cultures with adenovirus type 12. In the non-lytic infection of cultured hamster cells with adenovirus type 12, tumor antigen was formed as early as in human embryonic kidney cell cultures, but no infectious virus was formed. On the basis of these findings, the significance of tumor antigen in virus infection and the relationship between the virus infection and the transformation of hamster cells are discussed.