HBe항원 음성 만성간염 환자혈청에서 B형 간염 바이러스 C영역 DNA의 돌연변이 검색

Abstract

To estimate the diagnostic and infectivity evaluation efficiency of polymerase chain reaction (PCR) in chronic hepatitis B, twelve HBs antigen positive and HBe antigen negative sera from chronic hepatitis patients were tested by PCR. Serological markers were tested by ELISA. All the sera tested showed 270 bp DNA bands and were PCR positive, so PCR was proven to be a very efficient diagnostic and infectivity evaluation method in chronic hepatitis B. In order to investigate the mutations in HBe region DNA from HBe antigen negative sera of chronic hepatitis patients, PCR product DNAs were cloned into a T-vector system (pT7Blue) and the insert DNAs were identified by restriction enzyme digestion and by PCR. And the nucleotide sequences of HBe region DNA were analyzed by dideoxy-chain terminating method. In one serum tested, three point mutations were found in DNA sequences 2,119(Adenine to Thymine), 2,120(Adenine to Guanine), and 2,121 (Guanine to Thymine) resulted in two codon changes (GG A to GGT, AGT to GTT) and one amino acid change (serine to valine). In another serum tested, one point mutation was found in DNA sequence 2,062(Adenine to Guanine) resulted in one codon change (GCA to GCG). The mutations in core region DNA might alter the core protein structure and its protease function, that could results in breaking the HBe antigen production. Key Words: Hepatitis B virus, Core region DNA mutation, PCR.