FIG. 4.

Determination of the level of HCV RNA expressed in Huh7-hcvAS cells. Total RNA was extracted from cells and a clinical serum sample and then digested with DNase I prior to reverse transcription in the presence of a mixture of hexamer (pdN₆) oligonucleotides. Serial 10-fold dilution of cDNA was done before amplification with primers c256 and c186 (30). In the last four lanes, the reverse transcription step was eliminated prior to PCR amplification under conditions identical to those used for the first four lanes. PCR products were denatured and hybridized with ³²P-labeled internal primer c104 before being applied to a 6% polyacrylamide gel.