Long-term human T-cell culture system supporting hepatitis C virus replication

We recently found that human T-cell leukemia virus type I-infected cloned MT-2C cells could support the replication of hepatitis C virus (HCV) up to 30 days postinoculation (p.i.). To obtain a more persistent HCV replication system using MT-2C cells, we examined the effect of various culture conditions after virus inoculation. We found that persistent HCV infection (at least 80 days) could be reproducibly achieved by reducing the temperature from 37°C to 32°C. Under this culture condition, HCV RNA could be detected in the cells up to 198 days p.i. Sequence analysis of HCV hypervariable region 1 revealed that certain HCV species became predominant during the culture period. We also demonstrated that virus transmission by the cell-free mode could be successfully repeated at least 4 times at 32°C as opposed to only twice at 37°C. This HCV-infected culture system will be useful for the various biological studies, including investigations into the mechanisms of HCV replication and multiplication.