Direct intrafemoral injection of MND.Jak3 virus into Jak3^-/- mice. MND.Jak3 retrovirus (JAK3 RV) was administered to Jak3^-/- and control mice by DII according to the procedures described in “Materials and methods.” Two months following treatment, PB cells from control C57BL/6 mice (column 1), mock-injected Jak3^-/- mice (column 2), and MND.Jak3-injected mice (Jak3^-/- + JAK3 RV) (column 3) were analyzed for the presence of CD8⁺ and CD4⁺/62L⁺ T cells (% of total population indicated in quadrant).