Variability anlysis in Immunogenic Region of Hepatitis B virus: Sequence variation in Pakistanian Hepatitis B virus

The work was carried out to analyze variability in the immunogenic regions of surface envelope genes of Pakistanian Hepatitis B virus isolates. The PreS region, the hypervariable and highly immunogenic region, containing at least five epitopes, was PCR amplified, cloned and sequenced. Sequence alighnments and comparisons with other known HBV sequences from different parts of the world were performed in order to build a phylogenetic tree and to check if certain amino acids mutations tend to recur in certain places within the hypervariable region. On the basis of Phylogenetic analysis of PreS1 region from 12 newly sequenced Pakistanian HBV isolates, it appears that Genotype C is the most prevalent genotype in Pakistan and then comes Genotype D. It was also concluded that four mutations shared by NA004, NA018 and NA020 may be prevalent mutations in the Pakistanian ayw subtype. Six novel sequences and 13 mutations explored during this study may be specific to Pakistanian HBV isolates hence this information may be potentialy valuable for diagnostic puposes and for HBV vaccine development in Pakistan.