B 型肝炎病毒感染可能導致肝癌。在慢性 B 型肝炎病人血清中的 e 抗原分子和肝癌病人肝
組織取得的核心蛋白分子上有數個演化保留突變區。本實驗的目的是以抗體抗原結合的原理，欲
找出 e 抗原分子的抗原決定基部位，比較抗原決定基和保留突變區的相似性，以解釋 B 型肝炎病毒是否藉著突變的方式脫離免疫系統的辨識。介由電腦程式計算得到 e 抗原分子上的 7 段親
水性區域，並作成 7 段合成胜太，用合成胜太分別和 e 抗原對單株抗體做免疫競爭結合，以西方點墨免疫測試法和酵素連結免疫吸附測試法，做抗原抗體結合的分析。由基因表達、純化得到
的 e 抗原（SV），在定性測試和定量測試中，SV 蛋白和單株抗體有結合反應。另外以 20 位肝
癌病人血清測試純化的 SV 蛋白可得到 90% 的 e 抗體反應，表示單株抗體和純化的 SV 蛋白可用於e 抗原抗原決定基的定位。七段合成胜太分別對單株抗體做競爭結合反應，用酵素連結免疫吸附測試及西方點墨免疫測試法分析結果得知 7 段合成胜太不能與單株抗體做結合反應，然而所表達的重組 e 抗原分子能與單株抗體有免疫沉澱作用。

Hepatitis B virus (HBV) infection is strongly associated with hepatocellular carcinoma. The sequence of HBeAg in sera of hepatitis patients and the sequence of the entire core antigen in liver-derived HBVs of hepatoma patients reveal elevated mutation frequencies in the highly evolutionarily conserved regions.There may be a relationship between the regions of antigenic determinants of HBeAg and the regions of
elevated mutation frequencies of the liver-derived and naturally occurring HBVs. The antigenic epitopes of HBeAg were studied to explain how HBeAg variants accomplish immunoevasion via escape mutation
along the antigenic determinants of HBeAg recognized by T-cell and B-cell. Attempts were made to map antigenic determinants of HBeAg using a monoclonal antibody (MAb 8425). Seven potential epitopes of HBeAg were analysed by hydrophilicity and synthesized as peptides. HBeAg recombinant protein, SV, was tested for specific antigenicity with monoclonal antibody and sera from patients with hepatoma and used as a target protein for binding with monoclonal antibody. The blocking activity of each peptide in the binding of monoclonal antibody to the target protein was measured by Western blot immunodetection and ELISA.No blocking effect, by any of the peptides, was identified by either assay. We conclude that the recombinant HBeAg protein expressed in this study was able to compete with MAb for the binding to the HBeAg but the epitope mapping of HBeAg specific for MAb was not successful.