Objective: To study the association of the core and E1 region variation of hepatitis C virus (HCV) with the chronicity of HCV infection.
Methods: Acute-phase plasma samples from two drug-injection users who acquired HCV infection during six-month follow-up and ten patients with chronic hepatitis C were obtained. A 1-kb fragment containing the 3' half of core, completed E2 and 3' half of E2 were amplified by nested reverse transcription polymerase chain reaction (RT-PCR). For each 30 cloned cDNAs were examined by a method that combined heteroduplex (HD) analysis and a single-stranded conformational polymorphism (SSCP) assay to assess quasispecies complexity and optimize selection of clones with unique gel shift patterns for sequenceing. Amino acid sequences were analyzed for signature patterns and glycosylation signals.
Results: There was obvious difference between the SSCP bands of cloned cDNAs representing core-E1 region, but not obvious distance between heteroduplexes and the homoduplex. There was no change in the sequence of each clonotype from acutely HCV-infected subjects, whereas the rate of nonsynonymous substitution was 1.32% in amino acid sequence of E1 from persistently HCV-infected subjects with except for functional patterns.
Conclusions: The variation of the E1 gene of HCV is in the presence of quasispecies population but might not related with its immunologic escape.