A comparison of the replication cycles of simian virus 40 in human diploid and African green monkey kidney cells

Abstract

Simian virus 40 (SV40), which is capable of inducing transformation of human diploid cells, replicated to only a limited extent in WI-38 cultures and failed to cause any cytopathic changes. Less than 3 infectious particles were produced per cell in WI-38 cultures. In contrast, SV40 replicated extensively in primary African green monkey kidney cells (GMK) and in an established cell line (BS-C-1) obtained from GMK, with 100 and 50 infectious particles produced per cell, respectively. In addition, the virus caused extensive cytopathic changes in these cells. A comparison of the infectious cycle in a lytic (BS-C-1 and GMK) and in a transformable (WI-38) system, revealed that there was no difference in virus adsorption or entrance into eclipse in the two systems. Furthermore, there was no suppression of ribonucleic acid (RNA) or protein synthesis in WI-38 cells, nor in the stationary phase or replicating GMK cells following infection with SV40. The only early function that differed in the two systems was the production of SV40 Induced Complement Fixing Antigen (SV40 ICFA). Less than 3% of the WI-38 cells in a culture infected with a high multiplicity of virus developed SV40 ICFA during the first 7 days postinfection, whereas 80–100% of infected GMK cells were positive for ICFA 3 days after infection. There were marked differences in the infectious cycle of SV40 in replicating and stationary phase GMK cells. The yield of virus per cell, the development of cytopathic effects, and the production of SV40 ICFA were comparatively low in replicating cells; cells infected while replicating continued to multiply despite infection and have been subcultured 14 times since the addition of virus.