SUBTYPING OF THAI HEPATITIS-B VIRUS-DNA BY POLYMERASE CHAIN-REACTION

Polymerase chain reaction was modified and applied for subtyping of 20 0 sera of Thai hepatitis B virus (HBV) carriers. Four pairs of oligonu cleotide primers which derived from certain amino acids coded by the S gene were utilized for subtyping. First 2 pairs which contained the v ariations at amino acid residues 68 and 122 of the S gene product were used to subtype for d and y determinants, while the latters which had the variations at residues 47 and 213 were used for r and w determina nts. Southern-blot hybridization was used to confirm the amplified pro ducts as due to HBV-DNA. Furthermore, an immunological subtyping with monoclonal antibodies (immunodiffusion) was also conducted to verify t he PCR approach. The study revealed that all these Thai HBV-carriers w ere ad determinant positive which no ay were found at all, and they co uld be segregated as adr and adw subtypes as 81.0% and 19.0%, respecti vely.