Percentage eGFP-expressing cells in the lymph nodes of TC-transplanted animals. T cell–transplanted animals were killed after long-term follow-up of genetically modified mature T cells. eGFP expression (gated on CD45.1 and CD3) in the lymph nodes of killed animals (□) was compared with the input at transplantation (■) for each transplanted population. d indicates days after transplantation. n = number of transplanted animals. The high level of eGFP expression, even after a very long observation time, indicated that no vector silencing was observed. Error bars represent SD.