Figure 5. Additional immunosuppression and DST allow induction of chimerism and tolerance after transplantation of PBSC with costimulation blockade.
Transplantation of 200×106 (A, C) or 75×106 (B, D) PBSC leads to high levels of chimerism and donor-specific skin graft tolerance when DST and transient immunosuppression are added to costimulation blockade and 3 Gy TBI (protocol J). However, GVHD occurred in a large fraction of mice that had to be sacrificed. Panel A shows representative chimerism data from one of four separate experiments, panel C shows pooled skin graft data from all four experiments (n=18). Two-color FCM was used to determine chimerism among WBC at multiple time points post-HSCT. Chimerism levels are shown as mean. Donor and 3rd party skin were grafted 7-8 weeks after HSCT. IS denotes immunosuppression which was administered from d0 to 27.