iPsiRNA-transfected DCs simulate the induction of CTLs specific for a defined antigen. CTLs were induced by stimulation of autologous T cells with B51⁺ DCs loaded with the 19-aa precursor RU-1 polypeptide after no treatment (iDC), after transfection with control siRNA and the induction of DC maturation using CC (mDC + CsiRNA), or after transfection with siRNA targeting the 3 inducible iP subunits followed by induction of maturation (mDC + iPsiRNA). After 1 restimulation, T-cell IFN-γ release in response to the indicated target cells was assessed by ELISPOT (A), and cytolytic activity was assessed using the Europium release assay and either autologous iDCs (autologous iDC), the B51⁺ renal cell carcinoma cell line (RCC), or RCC preincubated for 1 week with IFN-γ to induce iP expression (RCC + IFN-γ) as targets (B). Values are plotted as means (± SD); *P < .05; ^@P < .01 for the comparison between T-cell activity induced by mDCs + iPsiRNA versus mDCs + CsiRNA; and ⁺P < .01 for the comparison between T cells induced by mDCs + CsiRNA versus iDCs.