Transformation of African green monkey kidney cells with the RF strain of human papovarivus BKVB

Abstract

Infection of semipermissive African green monkey kidney (AGMK) cells with human papovavirus RFV prodced a chronic infection with slow cytopathic effects. Prolonged maintenance of cell cultures in the presence of virus-neutralizing antibody resulted in the emergence of a stable cell line presently at the 100th generation intissue culture. The cell line MRF-325 has many of the properties of a tumor cell in culture, including increaed saturation density in monolayers, growth in soft agar and in suspension, and a decreased serum requirement for growth. Papovavirus T antigen and U antigen were detected in 100% of the MRF-325 nuclei by immunoperoxidase staining. No virion antigens were detected, and no infectious virions were isolated by cocultivation or fusion of MRF-325 with permissive human embryo kiney cells. Susceptibility of MRF-325 cells to SV40 infection was decreased compared to untransformed AGMK cells. MRF-325 cells supported high levels of replication of human adenovirus type 5 compared with nontransformed AGMK cells. Thus, RFV apparently provides a helper effect for adenovirus replication in AGMK cells similar to that observed for SV40.