title: A new vaccine escape mutant of hepatitis B virus causes occult infection.
abstract: There is growing public concern regarding assay sensitivity to HBsAg mutants in clinical diagnosis and vaccine escape. The aim of this study is to introduce a new HBsAg mutant strain. The serum samples were those of patient X at the age of 3 months and 3 years respectively, and of her mother immediately before parturition, which were used to amplify the HBsAg-coding DNA fragments by PCR. The HBsAg DNA sequences were translated into their corresponding amino acid sequences and then aligned in pubmed with nucleotide blast. The sequencing data of S coding regions shows that patient X has been infected by a new HBV variant with an A to C substitution at nt431, resulting in an Asp(GAC)to Ala(GCC) substitution at aa144 of major protein; CC to AA substitution at nt359 and nt360, resulting in an Pro(CCC) to Gln(CAA) substitution at aa120 of pre "a" epitope; A to G substitution at nt491, resulting in an Glu(GAG) to Gly(GGG) substitution at aa164 of post "a" epitope. Three new mutations (S171F, S174N and Q181R) at the antigenic epitopes of HBV presented by HLA class I molecules are found. The HBV mutant strain causes vaccine escape and occult infection.
authors.affiliation: a Clinical Laboratory; The Children's Hospital; School of Medicine ; Zhejiang University ; Hangzhou , PR China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Ye
authors.forename: Shi-Qiang
authors.initials: SQ
authors.lastname: Shang
authors.forename: Wei
authors.initials: W
authors.lastname: Li
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002675:Child, Preschool; D019295:Computational Biology; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D006509:Hepatitis B / Q000276:immunology / Q000473:pathology* / Q000821:virology*; D006514:Hepatitis B Surface Antigens / Q000235:genetics / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000276:immunology*; D006515:Hepatitis B virus / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D057131:Immune Evasion; D007223:Infant; D007231:Infant, Newborn; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines
keywords: ALP, alkaline phosphatase; ALT, alanine aminotransferase; AST, aspartate aminotransferase; AchE, acetylcholin esterase; Alb, albumin; Anti-HBc, antibodies to hepatitis B core antigen; Anti-HBs, antibodies to HBsAg; CMV, cytomegalovirus; CRP, C-reactive protein; EBNA, Epstein-Barr nuclear antigen; EBV, Epstein-Barr virus; EIA, enzyme immunoassay; HBV; HBsAg, hepatitis B surface antigen; HCV, hepatitis C virus; Hb, hemoglobin; LDH, lactate dehydrogenase; Plt, platelet count; RBC, red blood cell count; T-Bil, total bilirubin; TG, triglycerides; TP, total protein; UA, uric acid; VCA, viral capsid antigen; WBC, white blood cell count; anti-HA, antibody to hepatitis A; gene mutation; occult infection; vaccine escape; γGTP, γ-glutamyl transferase