A chimeric GB virus B encoding the hepatitis C virus hypervariable region 1 is infectious in vivo

1 The Macfarlane Burnet Institute, GPO Box 2284, Melbourne, VIC 3001, Australia 2 Department of Microbiology, Monash University, Clayton, VIC 3800, Australia 3 Department of Medicine (RMH/WH), University of Melbourne, Centre for Clinical Research Excellence, Royal Melbourne Hospital, Parkville, VIC, Australia Correspondence G. Haqshenas haqshenas{at}burnet.edu.au Two GB virus B (GBV-B) chimeric genomes, GBV-HVR and GBV-HVRh (with a hinge), containing the coding region of the immunodominant hypervariable region 1 (HVR1) of the E2 envelope protein of Hepatitis C virus (HCV) were constructed. Immunoblot analysis confirmed that HVR1 was anchored to the GBV-B E2 protein. To investigate the replication competence and in vivo stability of in vitro -generated chimeric RNA transcripts, two naïve marmosets were inoculated intrahepatically with the transcripts. The GBV-HVR chimeric genome was detectable for 2 weeks post-inoculation (p.i.), whereas GBV-HVRh reverted to wild type 1 week p.i. Sequencing analysis of the HVR1 and flanking regions from GBV-HVR RNA isolated from marmoset serum demonstrated that the HVR1 insert remained unaltered in the GBV-HVR chimera for 2 weeks. Inoculation of a naïve marmoset with serum collected at 1 week p.i. also resulted in viraemia and confirmed that the serum contained infectious particles. All animals cleared the infection by 3 weeks p.i. and remained negative for the remaining weeks. The chimera may prove useful for the in vivo examination of any HCV HVR1-based vaccine candidates. A supplementary table showing oligonucleotide primers designed and used in this study is available in JGV Online. These authors contributed equally to this work.