Monitoring antibody titers to recombinant Core-NS3 fusion polypeptide is useful for evaluating hepatitis C virus infection and responses to interferon-alpha therapy

To evaluate the clinical feasibility of the antibody titer against a chimer ic polypeptide (named Core 518), in which a domain of Core and NS3 of hepat itis C virus (HCV) was fused, ELISA was performed in a total of 76 serum sa mples. Each serum was serially diluted using two-fold dilution method with distilled water into 10 concentrations. They were all positive for second g eneration anti-HCV assay (HCV EIA II; Abbott Laboratories). Genotyping RT-P CR, quantitative competitive RT-PCR, and RIBA (Lucky Confirm; LG Biotech) w ere also assayed. Anti-Core 518 antibody was detected in x12800 or higher d ilutions of sera from 35 of 43 chronic hepatitis C (81.4%) and nine of 16 h epatocellular carcinoma sera (56.3%), one of four cirrhosis (25%), 0 of fou r acute hepatitis C, and one of nine healthy isolated anti-HCV-positive sub jects (p=0.0000). The anti-Core 518 antibody titers were well correlated wi th the presence of HCV RNA in serum (p=0.002), The anti-Core 518 antibody t iters decreased significantly in nine of ten responders to IFN-alpha treatm ent, Monitoring anti-Core 518 titers may be helpful not only for differenti ating the status of HCV infection among patients with various type C viral liver diseases, but also for predicting responses to IFN-alpha treatment.