Effect of timing of DLI on changes in chimerism. (A) Loss of chimerism induced by day-21 DLI. Results of one of 5 similar experiments are shown. Each line represents an individual animal; 6 animals/group. (B) Requirement for host αβ T cells for loss of chimerism induced by day-21 DLI. Means ± SD are shown. Wild-type recipients (B6): No DLI, n=6; DLI (30 × 10⁶ SPCs), n=8. TCRβ KO (TCR^–/–) recipients: No DLI, n=7; DLI (30 × 10⁶ SPCs), n=7. *Denotes statistically significant difference between DLI and no DLI groups.