Both CD4 and CD8 T-cell subsets contribute to conversion to full chimerism, whereas CD8 cells play a requisite role. (A-J) Time course of individual donor granulocyte chimerism (representative of both myeloid lineages followed; left panels) and donor CD4⁺ chimerism (representative of all lymphoid lineages followed; right panels). WBCs chimerism is shown for C57BL/6 (H2b) mice treated with CTX 200 mg/kg on day –1 and 7 Gy thymic irradiation on day 0 that received 20 × 10⁶ BMCs on day 0 and a final number of 30 × 10⁶ T-cell subset–depleted or undepleted SPCs on day 35 after BMT from B10.A (H2^a) mice. Recipients were given no DLI (n=9; A-B), complement only–treated DLI (n=11; C-D), CD4 cell–depleted DLI (n=12; E-F), CD8 cell–depleted DLI (n=11; G-H), or CD4 and CD8 cell–depleted DLI (n=20; I-J). Each line represents an individual animal in each panel. Data were pooled from 2 independent experiments.