Specific reactivity of human CTLs induced by SSP-1–loaded DCs in vitro. SSp-1–specific CTLs were generated from the PBMCs of 7 of 11 HLA-A2.1⁺ healthy donors through 4 sequential rounds of stimulation with SSp-1–pulsed DCs. Resulting CTLs were tested for IFN-γ release (A-B) and SSp-1–specific lysis (C) using an ELISPOT assay and a standard 4-hour chromium release assay. Autologous DCs (A) and T2 cells (B) were pulsed with indicated concentrations of SSp-1 (DC/SSp-1, T2/SSp-1) or irrelevant peptide CAP-1 (DC/CAP-1, T2/CAP-1), and then used as stimulators in an IFN-γ release assay. (C) CTLs lysed T2 cells loaded with SSp-1, but not T2 cells loaded with the irrelevant peptide CAP-1 or T2 cells alone. Results are representative of 3 independent experiments. Data represent means ± SD.