Detection of HCV-RNA minus strand after ethidium bromide–stained agarose gel of HCV-amplified products of 1 patient with chronic hepatitis, before and after stimulation of cells. Lanes 1 through 3, total PBMC at day 0, 7, 14; lanes 4 and 5, B lymphocytes at day 0, 7; lanes 6 through 8 and lanes 9 through 11, CD4⁺ and CD8⁺ cells at day 0, 7, 14 of stimulation, respectively. Day 0 corresponds to unstimulated cells. M, DNA size markers; N, negative control; P, positive control.