Lymphoid cells from the same healthy donor were stained with CFSE, PHA- stimulated and infected as described in Materials and Methods to measure proliferation of CD4+ and CD8+ T cell subsets.a Graphical representation of proliferation of T cell subsets after exposure to either NHP or HCV inocula. Proliferation represented by the mean percentage CFSE low ± SEM was measured at 4, 7 and 10 d.p.i. b The rates of T cell subset proliferation in cultures exposed to individual HCV inocula or NHP. Proliferation is represented by the mean percentage CFSE-low ± SEM measured at 3 different time points during the 10-d.p.i. culture