Quasispecies of Hepatitis B Virus

作     者：Qing He Qi-yuan Tang Xiao-hua Le De-liang Lv Xiang-mei Zhang Fei-jian Ao Yi-min Tang Shan Huang John Nunnari Gui-lin Yang 

作者机构：Shenzhen Institute of Infectious DiseasesShenzhen Third People’s Hospital Shenzhen Hospital for Chronic Diseases Control and Prevention Department of NeurobiologyUniversity of Massachusetts Medical School 

出 版 物：《国际感染病学（电子版）》 (Infection International(Electronic Edition))

年 卷 期：2012年第1卷第4期

页      面：177-182页

学科分类：1004[医学-公共卫生与预防医学(可授医学、理学学位)] 100401[医学-流行病与卫生统计学] 10[医学] 

主　　题：Quasispecies Hepatitis B virus Mutation 

摘      要：Hepatitis B virus(HBV) circulates in blood and replicates in the presence of quasispecies. During HBV replication, HBV DNA polymerase lacks fidelity and proofreading function partly because its exonuclease activity is either absent or deficient. Therefore, HBV genome is mutated with unusually high frequency. And these mutations can affect more than one open reading frame due to overlapping genes. Otherwise, natural substitutions, deletions or insertions involving the Cp/ENⅡ locus in the X gene can significantly alter the extent of viral replication activity. Particular selection pressures such as host immune system and antiviral therapy readily select out escape mutants from this pre-existing quasispecies pool. Antiviral drug resistance in chronic hepatitis B(CHB) can be caused by the viral mutation frequency, the intrinsic mutability of the antiviral target site, the selective pressure exerted by the drug, the magnitude and rate of virus replication, the overall replication fitness of the mutant, the genetic barrier of the compound and the availability of replication space. Potent inhibition of HBV replication could be able to prevent the development of drug resistance because mutagenesis is replication dependent. Viral load may decline to a point where the continued production of quasispecies with the potential to resist new drug treatments no longer occurs, if viral replication can be suppressed for a sufficient length of time.