The aim was to develop a cell culture system capable of producing high titer hepatitis C virus(HCV) stocks with recombinant vaccinia viruses as helpers.Two plasmids were used for the generation of recombinant HCV:one containing the full\|length HCV cDNA cloned between the T7 promoter and T7 terminator of the pOCUS\|T7 vector;and the other containing the HCV polyprotein open reading frame(ORF) directly linked to a vaccinia late promoter in the PSC59.These two plasmids were co\|transfected into BHK 21 cells,which were then infected with vTF7\|3 recombinant vaccinia helper viruses.After 5 days incubation,approximately 3 60±0 18×10 7 copies of HCV RNA were present per ml of cell culture supernatant,as detected by fluorescence quantitative RT\|PCR(FQ\|PCR).The yield of recombinant HCV using this cell system increased 10～100 fold compare to in vitro\| transcribed HCV genomic RNA or selectable subgenomic HCV RNA molecules method.These results suggest that this cell culture system is capable of producing high titer recombinant HCV. Furthermore,it may be useful as a system for future drug screening and vaccine selection.;
