Modified non-human mammalian hepatoma cell lines that express hepatitis C virus (HCV) antigens and which are capable of generating tumours in a syngeneic animal model are provided. The cell lines are generated by genomic integration of an expression construct that comprises one or more HCV antigen-encoding sequences under the control of a constitutive promoter. The expression construct further comprises a selectable marker and a reporter gene under the control of the same promoter. The cell lines are useful for testing prophylactic and therapeutic vaccines against HCV either in vitro or in vivo.