Nucleotide sequences of 5-1-1 of hepatitis C virus in patients with chronic liver disease.

The discovery of hepatitis C virus (HCV) has led to the development of an assay against a viral peptide (C100-3), which is now used worldwide. It has been shown that the majority of HCV-infected individuals are positive for the antibody. However, there are patients who are repeatedly seronegative for the antibody despite the presence of HCV RNA in the serum. The nucleotide sequences of 5-1-1 (a major epitope of C100-3) obtained from five antibody-positive patients and five negative patients with chronic liver disease were studied. The nucleotide identities of the seropositive and seronegative patients with HCV prototype sequence were 80.6% and 81.8%, respectively, not showing much difference in the nucleotide sequence of the 5-1-1 region. Moreover, no marked differences were noted in the deduced amino acid residues and the hydropathy profiles between the two groups. These data suggest that absence of the antibody in HCV carriers are not due to variations of major epitopes but are probably due to immunological incompetence against the synthetic C100-3 peptide.