FIG. 3.
Effect of low-pH treatment on the density distribution of HCV in an iodixanol density gradient. A serum sample from patient S6 with 6 × 106 IU of HCV RNA was incubated with PIPPS buffer, pH 4.0, and applied to an iodixanol density gradient prepared with the same buffer. The distribution of HCV RNA in the gradient was determined by RT-PCR and semiquantitated by densitometry from an agarose gel. A peak of HCV RNA was observed with a density between 1.10 and 1.12 g/ml, and HCV RNA was also observed toward the top of the gradient with a density below 1.08 g/ml.