Abstract: The present inventors developed hepatitis C virus recombinants expressing NS5A from genotype 1a, 1b, 2a, 3a, 4a, 5a, 6a or 7a in the context of a genotype 2a backbone. Additional recombinants express NS5A and the structural proteins (Core, E1 and E2), p7 and NS2 from genotype 1a, 1b, 3a, 4a, 5a, 6a or 7a in the genotype 2a backbone. Sequence analysis of the recombinants recovered after viral passage in Huh7.5 cells revealed adaptive mutations in NS5A and/or NS3. The importance of these mutations for improved growth kinetics was shown in reverse genetic studies.

Abstract: The present invention relates to nucleic acid sequences that encode hepatitis C viruses (HCV) that are useful in the fundamental research of HCV as well as in the search of a vaccine against HCV. In particular the present invention relates to nucleic acid sequences that comprises HCVs which are capable of expressing said virus when transfected into cells and are capable of infectivity in vivo.

Abstract: The present invention relates to nucleic acid sequences that encode hepatitis C viruses (HCV) that are useful in the fundamental research of HCV as well as in the search of a vaccine against HCV. In particular the present invention relates to nucleic acid sequences that comprises HCVs which are capable of expressing said virus when transfected into cells and are capable of infectivity in vivo.

Abstract: A robust and genetically stable cell culture system for Hepatitis C Virus (HCV) genotype 3a is provided. A genotype 3a/2a (S52/JFH1) recombinant containing the structural genes (Core, E1, E2), p7 and NS2 of strain S52 was constructed and characterized in Huh7.5 cells. S52/JFH1 and J6/JFH viruses passaged in cell culture had comparable growth kinetics and yielded similar peak HCV RNA titers and infectivity titers. Direct genome sequencing of cell culture derived S52/JFH1 viruses identified putative adaptive mutations in Core, E2, p7, NS3, and NS5A; clonal analysis revealed that all genomes analyzed exhibited different combinations of these mutations. Finally, viruses resulting from transfection with RNA transcripts of five S52/JFH1 recombinants containing these combinations of putative adaptive mutations performed as efficiently as J6/JFH viruses in Huh7.5 cells and were all genetically stable after viral passage.

Abstract: The present inventors developed hepatitis C virus 2b/2a intergenotypic recombinants in which the JFH1 structural genes (Core, E1 and E2), p7 and the complete NS2 were replaced by the corresponding genes of the genotype 2b reference strain J8. Sequence analysis of recovered 2b/2a recombinants from 2 transfection experiments revealed that 2b/2a was genetically stable. Conclusion: The developed 2b/2a viruses provide a robust in vitro tool for research in HCV genotype 2b, including vaccine studies and functional analysis.

Abstract: The present inventors developed 5a/2a intergenotypic recombinants in which the JFH1 structural genes (Core, E1 and E2), p7 and all of or part of NS2 were replaced by the corresponding genes of the genotype 5a reference strain SA13. Compared to the J6/JFH control virus, after transfection of in vitro transcripts in Huh7.5 cells, production of infectious viruses was delayed. However, in subsequent viral passages efficient spread of infection and HCV RNA titers as high as for J6/JFH were obtained. Infectivity titers were at all time points analyzed comparable to J6/JFH control virus. Sequence analysis of recovered 5a/2a recombinants from 2 serial passages and subsequent reverse genetic studies revealed adaptive mutations in p7, NS2 and/or NS3. Infectivity of the 5a/2a viruses was CD81 and SR-BI dependant, and the recombinant viruses could be neutralized by chronic phase sera from patients infected with genotype 5a.

Abstract: The present inventors developed three 4a/2a intergenotypic recombinants in which the JFH1 structural genes (Core, E1 and E2), p7 and all of or part of NS2 were replaced by the corresponding genes of the genotype 4a reference strain ED43. The 4a/2a junction in NS2 was placed after the first transmembrane domain (?), in the cytoplasmic part (?) or at the NS2/NS3 cleavage site (y). Following transfection of Huh7.5 cells with RNA transcripts, infectious viruses were produced in the ED43/JFH1-? and -y cultures only. Compared to the 2a control virus, production of infectious viruses was significantly delayed. However, in subsequent passages efficient spread of infection and high HCV RNA titers were obtained. Infectivity titers were approximately 10-fold lower than for the 2a control virus. Sequence analysis of recovered 4a/2a recombinants from 3 serial passages and subsequent reverse genetic studies revealed a vital dependence on a mutation in the NS2 4a part. ED43/JFH1-? further depended on a second NS2 mutation.

Abstract: The present inventors developed hepatitis C virus 2b/2a intergenotypic recombinants in which the JFH1 structural genes (Core, E1 and E2), p7 and the complete NS2 were replaced by the corresponding genes of the genotype 2b reference strain J8. Sequence analysis of recovered 2b/2a recombinants from 2 transfection experiments revealed that 2b/2a was genetically stable. Conclusion: The developed 2b/2a viruses provide a robust in vitro tool for research in HCV genotype 2b, including vaccine studies and functional analyses.

Abstract: The present inventors developed hepatitis C virus 6a/2a intergenotypic recombinants in which the JFH1 structural genes (Core, E1 and E2), p7 and the complete NS2 were replaced by the corresponding genes of the genotype 6a reference strain HK6a. Sequence analysis of recovered 6a/2a recombinants from 2 transfection experiments and subsequent reverse genetic studies revealed adaptive mutations in E1 and E2. Conclusion: The developed 6a/2a viruses provide a robust in vitro tool for research in HCV genotype 6, including vaccine studies and functional analyses.

Abstract: The present inventors have developed a culture system for genotype 3a, which has a high prevalence worldwide. Since intergenotypic recombinant genomes exploiting the replication characteristics of JFH1 will be a valuable tool for the genotype specific study of the replaced genes and related therapeutics, the present inventors constructed a genotype 3a/2a (S52/JFH1) recombinant containing the structural genes (Core, E1, E2), p7 and NS2 of strain S52 and characterized it in Huh7.5 cells. S52/JFH1 and J6/JFH viruses passaged in cell culture had comparable growth kinetics and yielded similar peak HCV RNA titers and infectivity titers. Direct genome sequencing of cell culture derived S52/JFH1 viruses identified putative adaptive mutations in Core, E2, p7, NS3 and NS5A; clonal analysis revealed, that all genomes analyzed exhibited different combinations of these mutations.