STP AND TIP ARE ESSENTIAL FOR HERPESVIRUS SAIMIRI ONCOGENICITY

Mutant forms of herpesvirus saimiri (HVS) subgroup C strain 488 with d eletions in either STP-C488 or Tip were constructed. The transforming potentials of the HVS mutants were tested in cell culture and in commo n marmosets. Parental HVS subgroup C strain 488 immortalized common ma rmoset T lymphocytes in vitro to interleukin-2-independent growth, but neither of the deletion mutants produced such growth transformation, Wild type HVS produced fatal lymphoma within 19 to 20 days of experime ntal infection of common marmosets, while HVS Delta STP-C488 and HVS D elta Tip were nononcogenic. Virus was repeatedly isolated from the per ipheral blood of marmosets infected with mutant virus for more than 5 months. These results demonstrate that STP-C488 and Tip are not requir ed for replication or persistence, but each is essential for transform ation in cell culture and for lymphoma induction in common marmosets.