IN-VITRO INFECTION OF PERIPHERAL-BLOOD MONONUCLEAR-CELLS BY HEPATITIS-C VIRUS

To study the in vitro susceptibility of peripheral blood mononuclear c ells (PBMC) to hepatitis C virus (HCV), we incubated cells from health y donors with HCV-positive sera. Using RT-PCR and in situ hybridizatio n, the genomic viral RNA was detected in PBMC and in their supernatant s until 25 days post-incubation. The PBMC of the different donors were not all permissive to HCV, but results were more constantly positive when cells from four donors were pooled. Quantification of the genomic viral RNA by the branched-DNA assay showed a decrease in the HCV RNA concentration during the first week of culture followed by a peak duri ng the second or third week, and also an increase in the total amount of viral RNA in the inoculated cells. Although HCV RNA could be detect ed in the supernatants by RT-PCR, the concentration was very low. Usin g a sense-specific RT-PCR method, the HCV negative-strand was also det ected in the cells but not in the supernatants. In two experiments PBM C were successfully infected using HCV-positive culture supernatants, therefore suggesting that infectious particles can be produced in this system. Our findings demonstrate that PBMC are permissive for HCV rep lication in vitro but the replication level is very low. The HCV RNA c oncentration measured in PBMC of 10 chronically infected patients was not significantly higher than the maximal concentration obtained in PB MC infected in vitro.