SV40 Transformation of Human Amnion Cells Under Different Culture Conditions 1

Summary SV40 transformation of primary cultures of human epithelial amnion cells depended on multiplicity of virus exposure, culture age, and medium. Under optimal conditions transformed foci were observed 12 days after infection. Morphological transformation frequency was 10-4. The percentage of cells containing T antigen early after infection was higher than reported for SV40 infected human fibroblasts. Early SV40 production was pronounced and similar virus titers were observed after high and low virus multiplicity within 3 weeks. The amount of growth and the period of time before “crisis” depended on the transfer schedule, but also showed a direct relationship to the original multiplicity of virus exposure.