Bone marrow B cells in reconstituted Rag2° and Rag2°γ_c°. Mice were analyzed 10 weeks after receiving transplants with 1 × 10⁴ sorted Lin-cKit⁺Sca1⁺ cells from wild-type C57Bl/6Ly5.1 mice. Age-matched C57Bl/6Ly5.1 mice were used for control. (A) Data represent profiles of CD19 versus CD25 expression on bone marrow cells from engrafted mice. (B) Profiles of CD19 versus IgM expression. Data represent profiles of gated CD45.1⁺ propidium iodide (PI)–negative cells. One representative analysis of at least 3 experiments is shown. Numbers indicate the absolute cell number in the respective quadrant. The dotted line separates the flow cytometric results from the unmanipulated C57Bl/6Ly5.1 from that of the reconstituted recipient mice.