Thymocyte reconstitution by bcl-2–deficient BM stem cells after intrathymic injection. Twenty-one days after intrathymic injection, mice were killed and single cell suspensions were prepared from thymuses. Cells were analyzed for the expression of Ly5.1 and Ly5.2, CD4, and CD8, or Ly5.2, CD4, CD8, and TCRαβ. Expression of CD4 and CD8 on donor-derived (Ly5.2⁺, Ly5.1⁻ cells) and TCRαβ expression in chimeric mice of bcl-2−/− HSCs or bcl-2+/− control chimeric mice are shown. Results shown are representative of five separate experiments.