Importance of SIRPα⁺ cDC2s for the splenic retention and rapid elimination of Cd47^−/− RBCs in WT recipient mice. (A) Representative flow cytometric plots for cDC subsets (left panel) and the absolute number of these cells (right panel) in the spleen of WT or XCR1^DTRvenus mice at 1 day after DTx treatment. Data in the right panel are means ± SEM for 3 mice. (B) Representative flow cytometric plots (left panel) and the percentage (right panel) of transfused CytoRed-positive Cd47^−/− RBCs among total splenic RBCs at 2 hours after injection of the labeled cells in WT or XCR1^DTRvenus recipient mice that had been treated with DTx 1 day previously. Data in the right panel are means ± SEM for 3 recipient mice. (C) Clearance of transfused Cd47^−/− RBCs from peripheral blood of WT or XCR1^DTRvenus recipient mice injected with the labeled cells at 1 day after DTx treatment. Data are means ± SEM for 3 recipient mice. (D) Representative flow cytometric plots for cDC subsets (left panel) and the absolute number of these cells (right panel) in the spleen of Sirpa^f/f or Sirpa^ΔDC mice. Data in the right panel are means ± SEM for 3 mice. (E) Representative flow cytometric plots (left panel) and the percentage (right panel) of transfused CFSE-positive Cd47^−/− RBCs among total splenic RBCs at 2 hours after injection of the labeled cells in Sirpa^f/f or Sirpa^ΔDC recipient mice. Data in the right panel are means ± SEM for 3 recipient mice. (F) Clearance of transfused Cd47^−/− RBCs from peripheral blood of Sirpa^f/f or Sirpa^ΔDC mice. Data are means ± SEM for 3 recipient mice. ∗P < .05; ∗∗P < .01; ∗∗∗∗P < .0001 by Student t test (A-B, D-E) or by 2-way repeated-measures ANOVA with Tukey’s multiple-comparison test (C,F). FSC-H, forward scatter height; NS, not significant.