Figure 6. Vaccine-induced HCV-specific cytolytic CTL remain detectable 6 wk beyond immunization. Putative cytolytic CTL, as defined by positive staining for both surface CD107a and intracellular granzyme B (GrzB), were induced by HCV immunization at 2 wk PIR in all NHPs. Cytolytic responses remained detectable 6 wk PIR in NHP716 and NHP 902 (●, NHP716; ◆, NHP004; ▲, NHP902; ■, NHP744).