In order to reactivate EBV-specific T-cells in B-CLL blood samples, 3610 7 cells were cultivated with 100 mg of exosomes in a final volume of 5 ml. Re-stimulations were performed on days 14 and 28 by adding 1610 7 lethally irradiated autologous PBMCs that have been loaded with 100 mg exosomes for 5h. Fresh medium was added once a week. After 31 days, cells were analyzed by flow cytometry for lineage markers. Interferon-cELISA assays were performed according to the manufacturers instructions (Mabtech, Uppsala, Sweden). The gp350-and BNRF1-specific CD4+ HLA-DR13-restricted T-cell clones used have been described elsewhere [8, 35] . All cells were tested in triplicates.