 All the donor specific T cell strategies discussed so far have utilized products derived from donors who are seropositive for the virus of interest. With the increasing use of cord blood CB grafts there are appreciable numbers of patients who are recipients of virus naïve donor grafts. CMV reactivation usually occurs from endogenous virus and seropositive recipients with seronegative donors remain the highest risk group for developing CMV. The development of multivirus specific T cells from recipients of cord blood grafts requires the priming of naïve T-cells rather than the simple expansion of pre-existing memory T-cells from seropositive donors. Using a protocol stimulating CB-derived T-cells with autologous CB-derived dendritic cells and EBV-LCL transduced with the Ad5f35CMVpp65 vector in the presence of IL-7, 12 and 15, multivirus specific T cells can be primed in vitro from the 20 fraction of a cord blood unit. So far, eight patients have received CTL as prophylaxis or treatment after CBT without toxicity. No infusion-related toxicitiesGvHD have been observed and despite receiving only 80 of the CB unit, all patients engrafted neutrophils within 30 days. Early evidence of efficacy has also been demonstrated with clearance of EBV, CMV and adenovirus in two patients and decreasing EBV viral load in a third with the other 5 patients remaining virus free. Therefore, these results suggest that transfer of naïve T cell CB-derived virus specific T cells to patients after CBT may be safe and facilitate long term reconstitution of virus-specific T-cells in vivo. 