Cross-priming of cyclin B1 specific CTLs.(a) Fluorescence microscopy analysis of cyclin B1 staining with T47D breast cancer cells. No staining with isotype control could be seen. (b) CTLs primed as described in Figure 3 killed T2 cells pulsed with cyclin B1 derived CB9 peptide, but not T2 cells pulsed with irrelevant (PSA) peptide, indicating the presence of cyclin B1-specific CTLs. Shown are representatives of three experiments. Values are expressed as average and standard deviation of triplicate wells. CTL, cytotoxic T lymphocyte; DC, dendritic cell.