Sequence analysis of hepatitis B virus S gene "a" determinant in patients with positive HBsAg and anti-HBs / 中华临床感染病杂志

ABSTRACT

Objective To identify the sequence of hepatitis B virus S gene"a"determinant in patients with positive HBsAg and anti-HBs.Methods Nested-PCR Was used to amplify the HBV S gene in 4 patients with positive HBsAg and anti-HBs,and the PCR products were sequenced directly or after cloning.The sequences of"a" determinants were then analyzed by sequence alignment.Results Direct sequencing of PCR products showed that there was one amino acid (aa)residue in"a"determinant less conserved region emerging polymorphism in all 4 patients.Clone sequencing showed that aa residue at 126 of "a"determinant in patient 1 miSht be Thr,Ile and Set,at 134 might be Phe and Set;the aa at 126 in patient 2 misht be Ala and Thr.and in patient 3 might be Ile and Asn;aa polymorphism was not found in patient 4.Conclusion The polymorphism of"a"determinant in HBV S gene might be associated with positivity of both HBsAg and anti-HBs in hepatitis B patients.