Figure 6

CD11b⁺Gr1⁺ population in donor-derived MDSCs is the effective suppressor subset. (A) Schematic illustration of the experimental design to study which subset in donor-derived MDSCs impart the immune suppressive function. C57BL/6 recipients received a single-dose intravenous injection of 1 × 10⁶ CD11b⁺Gr1⁺ or CD11b⁺Gr1^- or CD11b^- cells FACS isolated from BALB/c derived MDSCs 7 days prior to BALB/c derived cardiac graft transplantation. Whole MDSCs infusion and PBS administration groups served as positive and negative control. (B) Kaplan–Meier cumulative survival of allograft showing only CD11b⁺Gr1⁺ subset rather than CD11b⁺Gr1^- and CD11b^- subsets, reproduces similar allograft prolongation to the whole BALB/c MDSC infusion (p = 0.2459, no significant difference). Log-rank test. (C) Schematic diagram of the experimental design to study whether CD11b⁺Gr1⁺ population from MDSCs and cMDCs have the same immune suppressive function. C57BL/6 recipients received a single-dose intravenous injection of 1 × 10⁶ CD11b⁺Gr1⁺ cells FACS isolated from BALB/c MDSC or cMDC 7 days prior to the cardiac transplantation. (D) Kaplan–Meier cumulative survival of allograft showing CD11b⁺Gr1⁺ cells from MDSCs prolong allograft survival, while C57BL/6 mice treated with CD11b⁺Gr1⁺ cells from cMDC slightly accelerate the rejection. *p < 0.05, **p < 0.01, ***p < 0.001, log-rank test.