Smad7 alters the balance of lymphoid and myeloid cells following CB Lin^– SRC reconstitution. (A) A representative example of human engraftment in NOD/SCID mice repopulated with vector- (left column) or Smad7-transduced SRCs (right column) from the same CB sample. (i) Level of human engraftment in the NOD/SCID bone marrow, detected by the human specific pan-leukocyte marker CD45. (ii) Human CD45⁺ cells expressing the vector or Smad7 transgene were gated according to co-expression of GFP. (Inset) Dotplot for a mouse engrafted with nontransduced Lin^– cells, used to set quadrants for GFP⁺ human cells. (iii,iv) B-lymphoid and myeloid composition of the human hematopoietic graft in vector- and Smad7-transduced SRC (gated CD45⁺ in Figure 3Ai). Transduced B-lymphoid component expressed as percentage of CD19⁺ cells from total GFP⁺ cells (corresponding to GFP⁺ gate in Figure 3Aii). Transduced myeloid component expressed as percentage of CD33⁺ cells from total GFP⁺ cells. Nontransduced GFP^– human cells are shown in the left quadrants for comparison. Quadrant settings were based on CD45⁺ isotype controls from a mouse given transplants of nontransduced (GFP^–) CB Lin^– cells (inset). (B) Summary of the level of engraftment of human hematopoietic cells (% CD45⁺ cells) in the bone marrow of transduced NOD/SCID mice, calculated from gates shown in panel Ai, from 5 independent CB samples (13 mice total). Horizontal lines indicate mean level of engraftment; dots represent individual mice. (C) Summary of level of gene marking in the human hematopoietic graft, determined as percentage of GFP⁺ cells from total CD45⁺ cells, calculated from gates shown in panel Aii. Horizontal lines indicate mean level of gene marking; dots indicate the level of marking in individual mice. (D) Summary of engraftment patterns from vector (□) and Smad7 CB-paired mice (▪), from 5 independent CB samples transplanted into NOD/SCID mice (13 mice: 6 vector, 7 Smad7). Shown is the B-lymphoid (CD19⁺), myeloid (CD33⁺), and primitive (CD34⁺) populations expressed as percentage of total human (CD45⁺) GFP⁺ cells (i), or human (CD45⁺) GFP^– cells (ii) (± SEM). (E) Summary of engraftment patterns from vector (□) and Smad7 CB-paired mice (▪), from 4 independent CB samples transplanted into NOD/SCID/β2^–/– mice (18 mice: 8 vector, 10 Smad7). (F) Paired analysis of CD19 and CD33 engraftment patterns for vector and Smad7 SRCs from each of 5 CB samples transplanted into NOD/SCID mice. Bar indicates the mean percentage of CD19⁺ or CD33⁺ cells of the total GFP⁺ cells. *P ≤ .01. Error bars indicate SEM.