Recipient conditioning with pretransplantation Cy or fludarabine in conjunction with low-dose TBI and posttransplantation Cy induces engraftment of MHC-incompatible cells.
C57BL/10 (B10; H-2b) mice were conditioned with Cy 200 mg/kg intraperitoneally on day −3 (top panel) or fludarabine 100 mg/kg intraperitoneally daily on days −6 to −2 (middle and bottom panels), followed by 200 cGy TBI on day −1 and Cy 200 mg/kg intraperitoneally on day +3 (all panels). On day 0, conditioned recipients received no marrow (bottom panel) or 2 × 107 marrow cells from MHC-congenic B10.BR (H-2k) donors (top and middle panels). Six weeks later, donor chimerism in splenic CD4+ and CD8+ T cells and B220+ B cells was analyzed by dual-color flow cytometry. The numbers in each of the quadrants represent the percentage of total cells analyzed.
