Rescue of JAK3-mediated STAT-5 tyrosine phosphorylation in human ED-7R cells. The A2UCOE-IL2RG and SFFV-IL2RG lentiviral vectors (Figure 1B) were used to transduce human ED-7R cells at MOIs of 0.1, 0.5, 1, and 5. At 4 days following transduction, cells were stimulated with IL-2, subsequently stained with antiphosphorylated STAT-5 (pSTAT-5) antibody, and assessed for the presence of pSTAT-5 expression by FACS. The percentage of pSTAT-5–positive cells and MFI (in parentheses) is shown. Negative control indicates untransduced ED-7R cells stimulated with IL-2; positive control, ED-7R cells stably transfected with an IL2RG transgene.