Effect of titer escalation on e1a2Mz transduction into Ph⁺ ALL cell lines. KOPN-57 (A) and SUP-B15 (B) cells were transduced with the ECD2 or e1a2Mz vector at the indicated MOI. Cell death was determined by the trypan blue exclusion test on days 7 (▪) and 14 (▨). The results represent means ± SDs of triplicate experiments. ^*Numbers along the x-axis indicate the MOI of transduction.