CD8+ T-cell response promotes evolution of hepatitis C virus nonstructural proteins.

Background & Aims: Hepatitis C virus (HCV) acquires mutations that allow it to escape the CD8+ T-cell response, although the extent to which this process contributes to viral evolution at the population level is not clear. We studied viral adaptation using data from a large outbreak of HCV genotype 1b infection that occurred among women immunized with contaminated immunoglobulin from 1977 to 1978.

Methods: The HCV nonstructural protein coding regions NS3-NS5B were sequenced from 78 patients, and mutations were mapped according to their location inside or outside previously described CD8+ T-cell epitopes.