TRANSFECTION OF A DIFFERENTIATED HUMAN HEPATOMA-CELL LINE (HUH7) WITHIN VITRO-TRANSCRIBED HEPATITIS-C VIRUS (HCV) RNA AND ESTABLISHMENT OFA LONG-TERM CULTURE PERSISTENTLY INFECTED WITH HCV

T7 RNA polymerase transcripts of a putative full-length cDNA clone of hepatitis C virus type 1 (HCV-1) were used to transfect a differentiat ed human hepatoma cell line, Huh7. The transfected genome replicated i n cells, as evidenced by the appearance of progeny HCV RNA, detection of negative-strand viral RNA, and incorporation of [H-3]uridine into t he viral genome. Incubation of naive Huh7 cells with conditioned mediu m from transfected cells resulted in a new HCV infection, suggesting t he production of biologically active virus in the inoculum. Maintenanc e of the transfected cells under serum-free culture conditions resulte d in the selection of persistently infected cells which displayed a di stinctive cellular morphology. This is the first demonstration that HC V RNA produced from cloned HCV cDNA is infectious and replication comp etent. This approach should provide a valuable system for studying HCV replication, persistence, and pathogenicity.