In vivo proliferation of Bg1 CD8⁺ T cells in BM chimeric mice. A total of 1.5 × 10⁷ CFSE-labeled splenocytes (corresponding to 3 × 10⁶ CD8⁺ TCR-transgenic T cells) expressing the congenic marker Thy1.1 were adoptively transferred into the indicated Thy1.2⁺ bone marrow chimeras. (A) C57BL/6→C57BL/6 (B6 → B6). (B) Tie2-LacZ → Tie2LacZ (T2 → T2). (C) C57BL/6 → Tie2-LacZ (B6 → T2). (D) Tie2-LacZ × B6.C-H2^bm1 → Tie2-LacZ (T2 × bm1 → T2). (E) Tie2-LacZ × B6.C-H2^bm1 → Tie2-LacZ × B6.C-H2^bm1 (T2 × bm1 → T2 × bm1). (F) C57BL/6 → Tie2-LacZ × B6.C-H2^bm1 (B6 → T2 × bm1). (G) CD11c DTR → Tie2-LacZ × B6.C-H2^bm1 (CD11cDTR → T2 × bm1). CD11c-DTR BM recipients had been injected intraperitoneally with 4 ng/g body weight diphteria toxin (DT), which led to a 95% to 98% depletion of CD11c⁺ cells for more than 48 hours. Mice were killed on day 4 following adoptive transfer and cells from blood and spleens were analyzed by flow cytometry. Values in the histograms represent mean percentages (± SEM, n = 5-7; pooled data from 3 independent experiments) of proliferating CD8⁺Thy1.1⁺ cells.