Preparation and purification of core protein from HBV Genotype G HBV/G-infected individuals were identified through routine diagnostic testing and strain surveillance at the National Microbiology Laboratory (NML) using sequencing and phylogenetic analysis [10] . The gene coding for the HBV/G core protein was PCR amplified, cloned into the pET28b vector (Novagen, EMD Biosciences, Gibbstown, NJ, USA) and expressed in Escherichia coli strain BL21 (DE3). Clarified culture lysates were centrifuged on a 20-60% sucrose gradient at 30 000 rpm in a Beckman SW4OTi rotor for 14 h. Fractions were analysed by SDS-PAGE and Western blotting with anti-HBc antibody (MA1-21697; Pierce Antibody, Rockford, IL, USA). Cores were dialysed against PBS pH 7.4 using a 10 K MW cut off Pierce Slide-A-Lyzer cassette (Thermo Scientific, Waltham, Massachusetts, USA). The HBV/G core sequence was submitted to the National Center for Biotechnology Information GenBank database under accession number GU325783.