Anti-CD3 preconditioning inhibited donor T-cell infiltration of GVHD target tissues. Five days after injection of donor TCD-BM and spleen cells (5 × 10⁶), the percentage and yield of donor T cells in spleen, MLNs, PLNs, liver, gut, and skin of the recipients with or without anti-CD3 preconditioning were compared. There were 4 recipients in each group. (A) A representative FACS pattern. Mononuclear cells from different tissues were stained with anti-TCRαβ versus anti-H-2^b (donor MHCI), and the donor-type T cells were gated. (B) Mean plus or minus SE of the donor T-cell percentage among total mononuclear cells of 4 recipients. (C) Mean plus or minus SE of the yield of donor T cells in different tissues. (D) A representative intracellular IFN-γ staining pattern of the gated H-2^b+CD4⁺ or H-2^b+CD8⁺ T cells. The IFN-γ⁺ cells were gated. (E) Mean plus or minus SE of the percentage of donor IFN-γ⁺CD4⁺ or CD8⁺ cells of 4 examined recipients. (F,G) Mean plus or minus SE of serum IFN-γ and TNF-α levels of 6 examined recipients.