Transfer of HLA-A2 molecules from HLA-A2⁺ DCs to HLA-A2^-DN and CD8⁺ T-cells. FACS-sorted DN and CD8⁺ T cells from an HLA-A2^- donor were cocultured with mature HLA-A2⁺ DCs at a ratio of 1:1. At indicated time points cells were harvested and analyzed for the expression of HLA-A2 on forward/side scatter (FSC/SSC)–gated lymphocytes. (A) Histograms show the kinetics (before, 24 hours, and 48 hours after coculture) of HLA-A2 expression (solid lines) on DN T cells from 2 healthy donors (left column, donor no. 1; right column, donor no. 2) after coculture or in a transwell system. Open lines indicate isotype control. (B) Percentage of HLA-A2⁺ DN (▪) and CD8⁺ T cells (○) from HLA-A2^- donors at different time points of coincubation with HLA-A2⁺ DCs are shown.