Detection of CD4+ and CD8+ T lymphocyte responses to HCV vaccine in immunized mice using IFN-γ ELISPOT assay. ELISPOT counts (spot-forming units [SFUs]/1 × 106) in response to core, E1 and E2 protein, Core peptides, or vaccinia HCV poly. Spot forming cell (SFC) frequencies are shown after subtraction of background with unstimulated cells or empty vaccinia stimulated cells. Cells were incubated with core, E1 and E2 protein, Core peptides, or vaccinia HCV poly for 48 hrs before measuring IFN-γ ELISPOT responses. Spot forming cell (SFC) frequency per million cells is indicated for each immunized and non-immunized donor mice. The P value was < 0.05.