Analysis of retrogenic mice. 3D TCR-transduced Rag2^−/− BM cells (Thy1.2) were transferred into irradiated Thy1.1 B6 recipients and analyzed more than 5 weeks posttransfer. (A) Splenocytes were analyzed for Thy1.2 expression by flow cytometry as a marker of donor-derived cells, which were gated and analyzed for CD4, CD8, and TCRβ expression. (B) Thymocytes from retrogenic mice were analyzed for Thy1.2 expression, and donor cells were then analyzed for CD4 and CD8 expression. Because the only marker of successful transduction was retrogenic TCR expression by the Rag2^−/− cells, TCRβ⁺ cells were gated and analyzed for CD8, CD69, and CD5 expression.