The acquisition of the defective SV40 genome by a variety of human adenovirus serotypes by the process of transcapsidation has resulted in the addition of oncogenic potential for newborn hamsters to the previously nononcogenic adenovirus types 1, 2, 5, and 6. These serotypes have previously been grouped together by the high GC content of their DNA.
Transcapsidation of the SV40 genome to weakly oncogenic adenovirus types 3, 14, 16, and 21 has failed to increase their oncogenic potential although the parent adenovirus type 7 carrying PARA is highly oncogenic. These serotypes belong to the group possessing a DNA of intermediate GC content.
All the PARA-adenovirus populations, even those that were nononcogenic, were able to induce SV40 transplantation immunity and therefore carry the SV40 transplantation marker as well as the marker for synthesis of SV40 tumor or T antigen.