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Full-length complementary DNA of hepatitis C virus genome from an infectious blood sample
1Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan.
Insights
Researchers created a full-length hepatitis C virus (HCV) complementary DNA (cDNA) clone from infected blood. This clone, derived from specific virus variants, was infectious to humans and chimpanzees, offering insights into HCV transmission and evolution.
Area of Science:
- Virology
- Molecular Biology
- Hepatology
Background:
- Hepatitis C virus (HCV) infection remains a significant global health concern.
- Understanding HCV's genetic diversity and transmission dynamics is crucial for developing effective therapies.
- Previous studies highlighted the heterogeneity of HCV within infected individuals.
Purpose of the Study:
- To construct a full-length complementary DNA (cDNA) clone of the hepatitis C virus (HCV).
- To investigate the genetic characteristics and transmission patterns of HCV clones.
- To identify the origin of infectious virus clones within a transmission chain.
Main Methods:
- Isolation and subcloning of 12 overlapping cDNA fragments covering the entire HCV genome.
- Sequencing of cDNA fragments to identify and select major viral populations.
- Construction of a full-length HCV cDNA clone by combining sequenced fragments.
- Infectivity studies in humans (post-transfusion) and chimpanzees.
Main Results:
- A full-length HCV cDNA clone was successfully constructed from a carrier's blood sample.
- The transmitted HCV population in a recipient and chimpanzee showed convergence towards specific clones.
- Virus clones isolated during the acute phase in both the recipient and chimpanzee were identical to the full-length cDNA clone's hypervariable region.
- The donor's HCV population was genetically heterogeneous, with specific clones selected post-transmission.
Conclusions:
- The constructed full-length HCV cDNA clone likely represents an infectious virus clone.
- HCV transmission involves the selection and amplification of specific viral variants from a heterogeneous population.
- This study provides a valuable tool for further research into HCV pathogenesis and antiviral development.
Abstract:
We constructed a full-length complementary DNA (cDNA) clone of hepatitis C virus (HCV) from a blood sample of an HCV carrier. The blood from the carrier was eventually transfused to a patient who later developed typical posttransfusion hepatitis C. It was also shown to be infectious to chimpanzees. We obtained 12 overlapping cDNA fragments altogether, covering the entire HCV genome. By subcloning and sequencing, clones considered to constitute the major population were selected. We could also detect 98 base pairs of extra sequences at the 3' end of the genome. After confirming the overlapping sequences, we combined the fragments to make a full-length cDNA. The HCV population in the donor was heterogeneous, as determined by their nucleotide sequences of the hypervariable region in envelope protein, but a few virus clones were selected in the recipient after transmission. The similar convergence of the virus population was previously observed when the same blood sample was injected into a chimpanzee. Interestingly, virus clones isolated during the acute phase in the recipient and the chimpanzee had sequences in the hypervariable region identical to that of the full-length cDNA clone. The full-length cDNA clone of HCV constructed in this study may originate from infectious virus clones.