Cross-priming of survivin peptide-specific CTLs. HLA-A*0201+ naïve CD8+ T cells (CD45RA+CD45RO-CCR7+) were stimulated twice with autologous DCs loaded with killed allogeneic HLA-A*0201+ MCF-7 breast cancer cells in 2-week cultures supplemented with IL-7 and IL-2 (10 U/ml). Seven days after the second stimulation, the T cells were harvested, washed, and restimulated once with autologous DCs loaded with an overlapping peptide library derived from survivin protein. After an additional 7 days of culture, T cells were cultured for 6 hours with DCs pulsed with survivin derived peptides (x-axis), Golgi stop was added in the last 4 hours of cocultures, and the presence of specific T cells was measured by intracytoplasmic staining with anti-IFN-γ mAb and flow cytometry. Percentage of IFN-γ producing CD8+ T cells is shows on the y-axis; values are expressed as average and standard deviation from three independent experiments. CTL, cytotoxic T lymphocyte; DC, dendritic cell; IFN, interferon; IL, interleukin; mAb, monoclonal antibody.