Oncogenic potential of human herpesvirus-6 DNA.

The ability of human herpesvirus-6 (HHV-6, GS strain) DNA to neoplastically transform established NIH3T3 cells was examined. Transfection of NIH3T3 cells with the intact genomic DNA (170 Kb) or the subgenomic clone pZVH14 containing an 8.7 Kb insert followed by focal or G418 selection resulted in the formation of morphologically transformed cells. When injected subcutaneously into nude mice, these cell lines gave rise to rapidly growing tumors while cells transfected with control vector DNA did not grow in agarose and did not produce tumors in mice. By Southern blot analysis, HHV-6 DNA was detected in the G418 selected primary transfectants and tumor cell lines, but not in the focus derived transformed and tumor cell lines. The data suggest that HHV-6 DNA contains sequences which may contribute to neoplastic transformation, but are not likely to be required for maintenance of transformation.