Gamma retroviral vectors and experimental design. (A) The design of the retroviral vectors used in this study. The retroviral vector SF91-ΔTrkA has been described elsewhere.¹⁰  wPRE indicates Woodchuck hepatitis virus posttranscriptional regulatory element; IRES, internal ribosomal entry site. An HA-tagged LMO2 was used for Western blot analysis. (B) C57BL/6.Ly5.1 mice were used as donors for Sca1⁺ HSCs/HPCs and mature T cells. Isolated Sca1⁺ HSCs/HPCs were stimulated for 3 days, mature T cells for 4 days, followed by retroviral transduction and transplantation into RAG-1–deficient recipient mice. After 12 to 16 weeks, animals that received T-cell transplants developed massive colitis and were killed. T cells were isolated and serially transplanted several times into secondary recipients (1 donor to 1 recipient).