[Cloning and expressing of HCV NS5 partial gene and dynamic changes of anti-NS5]

To study antigenicity of HCV NS5 protein and dynamic changes of anti-NS5 in post-transfusion hepatitis C (PT-HC).

Epitopes of HCV NS5 protein were analyzed by Goldkey Program. NS5 gene fragment was amplified by reverse transcription and polymerize chain reaction (RT-PCR) from sera of PT-HC patients. Sequence analysis was performed, and recombinant strain was constructed. Series sera from PT-HC were detected for anti-NS5, ALT and HCV RNA.

The homology of nucleotide and amino acid with genotype II in the same region was 91.8% and 92.4%, respectively. SDS-PAGE analysis showed an expressing band around 50 kD, the fusion protein represented about 21.4% of total bacterial protein. Western blot result proved the expressing band could specifically react with sera from hepatitis C patients. Detection results of series blood samples from PT-HC showed that the antibody against NS5 appeared relatively late, the positive conversion time was 182.9 +/- 168.5 day. Dynamic changes of anti-NS5 were correlated with serum ALT in most cases. The types of dynamic change of anti-NS5 were passing positive; intermittent positive; persistent positive, and persistent negative in two years.

Antibody against NS5 may reflect the disease activity to some extent. It appears relatively late, and is of no value in early stage diagnosis.