IFN-γ treatment of Fancc^-/- recipients is sufficient to allow engraftment of syngeneic WT bone marrow cells. (A) CD45.1⁺ WT BM nucleated cells (10⁷) were injected into the tail vein of WT and Fancc^-/- C57Bl/6 recipients that express the CD45.2 antigen. Recipients were pretreated with IFN-γ or vehicle control. The percentage of CD45.1⁺ cells in the peripheral blood was determined by fluorescence cytometry 6 months following treatment. Data points represent CD45.1⁺ chimerism of individual mice. Bars represent the mean CD45.1⁺ chimerism. ^*P < .001 comparing chimerism of Fancc^-/- recipients treated with IFN-γ-versus vehicle-treated Fancc^-/- recipients and WT recipients. (B) Myeloid and lymphoid differentiation of isogenic WT cells in Fancc^-/- mice was determined using fluorescence cytometry 6 months subsequent to IFN-γ treatment. Multilineage analyses of 2 representative mice with 69% and 51% CD45.1⁺ chimerism are shown. The percentage of WT CD45.1⁺ lymphoid (CD3 and B220) and myeloid (Gr1 and Mac1) cells is shown in the top right corner of each fluorescence-activated cell sorter (FACS) profile. (C) To evaluate long-term repopulating ability of syngeneic WT BM cells from primary recipients pretreated with IFN-γ, secondary recipients were reconstituted using bone marrow cells from primary recipients 6 months following IFN-γ treatment. CD45.1⁺ chimerism of secondary recipients was measured 4 months following transplantation. Bars represent the mean CD45.1⁺ chimerism. ^*P < .001 comparing chimerism of Fancc^-/- recipients treated with IFN-γ-versus vehicle-treated Fancc^-/- recipients and WT recipients.