An infectious molecular clone of a Japanese genotype 1b hepatitis C virus

We describe an infectious molecular clone of a Japanese genotype Ib strain of hepatitis C virus (HCV-N), The molecularly cloned sequence of HCV-N was compared with alignments of other HCV sequences, leading to the identificat ion of 15 unique, nonconservative amino acid substitutions within the HCV-N open reading frame (ORF), These were repaired to the consensus genotype 1b residue, and the infectivity of RNA transcribed from the repaired clone wa s assessed by intrahepatic inoculation of a chimpanzee. Viral RNA was first detected in the serum of this chimpanzee 3 weeks following inoculation, an d was intermittently present over the next 14 weeks. A strong and persisten t anti-HCV serological response developed 13 weeks following inoculation, w ith seroconversion in the recombinant immunoblot assay (RIBA), A weaker, tr ansient serological response, characterized by seroconversion in a third-ge neration enzyme-linked immunosorbent assay (ELISA) but not RIBA, occurred b etween weeks 1 and 5, This may have represented an anamnestic response to H CV antigens translated directly from the intrahepatically inoculated RNA, b ecause the animal previously had undergone 2 unsuccessful attempts at rescu e of HCV by intrahepatic RNA inoculation. There was neither biochemical nor histological evidence of liver disease. Although this is within the range of expected outcomes in an HCV-naive chimpanzee, prior immunologic priming may have modified the infection in this animal. The HCV-N clone is the firs t infectious molecular clone of HCV that is comprised entirely of genotype 1b sequence, and it contains an ORF sequence that is significantly divergen t from that of a previously described genotype 1a/1b chimera.