Coinfusion of allogeneic splenocytes facilitates engraftment of BM and homing of allogeneic BM to GVHD target organs. B10.BR mice (for allogeneic studies) or C57BL/6 mice (for syngeneic studies) were lethally irradiated and given BM from eGFP Tg C57BL/6 mice with or without whole splenocytes from non-eGFP C57BL/6 mice. Early time points (1-72 hours after BMT) for the liver (A) and Peyer patches (B) are shown. Day 7 time points are shown for liver (C, L), lung (D), spleen (E), femur (F), skull (G), brain (H), Peyer patch (I), ileum (J), and thymus (K). Tissues from 1 of 3 representative mice from each time point per group are shown. Stereomicroscope was set to 10.0 × zoom factor with a 0.5 × transfer lens. (L) Confocal analysis of immunofluorescence costaining in the liver of a mouse given allogeneic eGFP Tg BM and non-eGFP splenocytes for phenotypic identification of donor eGFP Tg BM-derived cells on day 7 after BMT. Cryosections were costained with anti-eGFP antibody (red) and the indicated phenotypic marker (blue). Costained cells are depicted as violet-purple. Donor eGFP Tg BM-derived cells expressing CD8, CD19, CD11b, Gr-1, and donor MHC class 2(I-A^b) were seen. Original magnification × 200.