OBJECTIVE?To study the structural and preliminary functional characterization of the hepatitis B virus(HBV) enhancer Ⅰ in patients with chronic hepatitis B treated with interferon (IFN).?METHODS?The characteristics of the HBV enhancer Ⅰin 12 chronic carrier who were treated with alpha interferon was detected by the methods of molecular biology including PCR, cloning of PCR products, sequencing and cell culture.? RESULTS ?Four of 6 patients cleared viral DNA; all 6 in this group also seroconverted from e antigen to antibody. Prior to therapy, the HBV enhancer Ⅰ region demonstrated many point mutations in all 6 patients who became nonresponders, compared to patients who responded to interferon. The mutated sequences, many of which were within regions of transcription factor binding, were significantly more active than the corresponding wild type sequences in reporter gene assays.?CONCLUSION? These results imply that the mutations found in nonresponders appear to render the virus less sensitive to interferon. OBJECTIVE? To study the structural and preliminary functional characterization of the hepatitis B virus (HBV) enhancer I in patients with chronic hepatitis B treated with interferon (IFN).? METHODS? The characteristics of the HBV enhancer Iin 12 chronic carrier who were treated with alpha interferon was detected by the methods of molecular biology including PCR, cloning of PCR products, sequencing and cell culture.? RESULTS? Four of 6 patients cleared viral DNA; all 6 in this group also seroconverted from e antigen to antibody. Prior to therapy , the HBV enhancer Ⅰ region demonstrated many point mutations in all 6 patients who became nonresponders, compared to patients who responded to interferon. The mutated sequences, many of which were within regions of transcription factor binding, were significantly more active than the corresponding wild type sequences in reporter gene assays .?CONCLUSION? These results imply that the mutations found in nonresponders appear to render the virus less sensitive to interferon.