Excessive hematopoietic reconstitution after BM transplantation with CCL3^−/− donor cells. A total of 1 × 10⁷ BM cells harvested from the femoral and tibial bones of CD45.2⁺ WT or CCL3^−/− mice were intravenously injected into sublethally irradiated CD45.1⁺ congenic mice to establish the primary BM chimera. Total BM cells were harvested from primary BM chimeric mice at 8 weeks after transplantation and subsequently subjected to the secondary BM transplantation. (A) The numbers of donor-derived total WBCs excluding T-cell receptor (TCR)–β chain⁺ T cells, CD19⁺ B cells, and Ly6G⁺ granulocytes in PB. Their numbers in the PB of untreated WT and CCL3^−/− mice are shown by the columns. Data represent means ± SD from 4 to 6 independent experiments. (B) The numbers of donor-derived CD34⁻KLS⁺ HSCs and CD34⁺KLS⁺ MPPs were determined in the tibial BMs of nontreated mice and each BM chimera at 8 weeks after transplantation. Data represent means ± SD from 4 independent experiments. (C) Ki67 and CD34 expression in the KLS⁺ cells in the tibial BMs of untreated and BM chimeric mice at 2 weeks after transplantation with WT donor cells. Percentages of Ki67^high cells in CD34⁺ and CD34⁻ region are shown. Representative results from 4 independent experiments are shown. (D) Proportion of Ki67^high cells among the KLS⁺ cells at the indicated time points after BM transplantation. Data represent means ± SD from 4 experiments. (A,B,D) *P < .05; **P < .01; N.S., no significant difference by the Mann-Whitney U test.