Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: A novel nucleotide insertion in S gene of hepatitis B virus in a chronic carrier | Tong et al. Virology Journal 2010 7 104 http content 7 1 104 VIROLOGY JOURNAL RESEARCH Open Access A nlovel nucleotide insertion in S gene of hepatitis B virus in a chronic carrier Wenbin Tong Li Sun Jilan He Shusen He and Fei Du Abstract Hepatitis B virus DNA was extracted from serum of a chronic carrier and polymerase chain reaction was performed on S gene. Direct sequencing showed a variant HBsAg with additional 4-amino acid insertion and clone sequencing confirmed the mixture of variant HBsAg and wildtype HBsAg. Of 16 clones with 12-nucleotide insertion 15 clones had identical AGAACAACACAA insertion between nucleotide 494 and nucleotide 495 and one clone had GGAACAACTCAA insertion in the same position plus 3-nucleotide deletion from nucleotide 491 to nucleotide 493. S114T C121Y T126S A Q129K G130R T131N M133T G145R N146D substitution and premature stop codon were also found in those clones. However the origin of HBV with 4-amino acid insertion in HBsAg was unclear. Introduction Hepatitis B virus HBV infection is a global health problem. It was estimated that more than 2 billion of the global population had been infected. Of these approximately 360 million were chronically infected and estimated 500 000-700 000 people died from complications of infection each year worldwide 1 . HBV infection was highly endemic in China a national serosurvey conducted in 2006 showed surface antigen HBsAg prevalence in population aged 1 59 years old 2 . Control and therapy of HBV-related diseases weighed great burden on both government and infected individual 3 . HBsAg a main serological marker for diagnosis of HBV infection comprises 226 amino acids aa and contains a highly conformational epitope cluster in major hydrophilic region MHR extending from aa99-aa169 where common a determinant is located at aa124-aa147 4-6 . Antibodies induced by natural infection or by administration of vaccine direct against a determinant and confer cross-protective immunity to
