Demonstration of sugar moiety on the surface of hepatitis C virions recovered from the circulation of infected humans.

The amino acid sequence for the envelope protein(s) predicted from the nucleotide sequence of the E and E2/NS1 regions of the hepatitis C virus (HCV) genome is enriched with an N-linked glycosylation site motif, Asn-X-Thr/Ser, suggesting oligosaccharide moieties are present on the virion surface. We attempted to characterize the sugar moiety on the surface of HCV virions recovered from sera of infected humans to assess the natural properties of the virus. Six kinds of lectins were used to bind HCV virions in affinity column chromatographies: RCAI, WGA, Con A, AAL, LCA, and PNA. Lectin-bound virions were identified by detecting HCV RNA in eluted chromatography fractions with a polymerase chain reaction (PCR) method. Our results showed that HCV was similar to hepatitis B virus (HBV) in characteristics of binding to lectins: HCV showed a strong binding to RCAI and WGA, weak binding to Con A, and no detectable binding to AAL, LCA, or PNA. Treatment of the HCV virion preparation with an enzyme, glycopeptidase A, or a detergent, NP-40, resulted in a significant decrease in the ability to bind these lectins. Our results suggest that asparagine-linked sugar chains are present on the surface of native virions of HCV, very similar to those for HBV.