The Physical State of the Negative Strand of Hepatitis C Virus RNA in Serum

Both plus and minus RNA strands (+RNA and -RNA) of hepatitis C virus (HCV) have been described in sera from infected hosts. We assessed the physical state of the -RNA of HCV using CsCl-isopyknic ultracentrifugation and strand-specific reverse transcriptase-polymerase chain reaction. The +RNA was detected at a density of 1.10–1.28 g/cm3, with the -RNA at 1.10–1.16 g/cm3. When treated with a detergent, the +RNA density shifted to 1.35 g/cm3, and the +RNA became undetectable. The +RNA was resistant to RNase even after treatment with detergent, but the -RNA became RNase-sensitive after treatment. The +RNA was coated with proteins recognized by anti-core- and anti-E1-specific antibodies, whereas the -RNA was associated only with anti-E1-reactive proteins. These results suggest that -RNA of HCV is present in the infected sera as a membrane particle associated with E1 protein.