Abstract
Human papillomaviruses (HPVs) infect the stratified epithelial organ. The infection induces benign tumors, which occasionally progress into malignant tumors. To elucidate the virus-induced tumorigenesis, an understanding of the lifecycle of HPV is crucial. In this report, we developed a new system for the analysis of the HPV lifecycle. The new system consists of a novel HPV replicon and an organotypic "raft" culture, by which the HPV-DNA is maintained stably in normal human keratinocytes for a long period and the viral vegetative replication is reproduced. This system will benefit biochemical and genetic studies on the lifecycle of HPV and tumorigenesis. This system is also valuable in screening for antiviral compounds. We confirmed its usefulness by evaluating the antivirus effect of cytokines.