Figure 4.

Monocytes give rise to RPMs in the spleen during the recovery from anemia posttransplant. (A) Schematic for monocyte lineage tracing in middle and late recovery stage, where monocytes were donor derived. Cx3cr1^{YFPCreER;tdTomato} donor mice were IP injected with tamoxifen in corn oil at 75 mg/kg body weight consecutively for 5 days. BM cells were obtained and transplanted into CD45.1 recipient mice. Flow cytometry analysis was done on cells first gated on CD45.2⁺ donor cells from day 8, day 10, day 14, and day 16 after transplant. Gating strategies used in Figure 2A were used. n = 3-4 for each group per time point. (B-D) Characterization of monocyte and macrophage subpopulations in YFP^negtdTomato⁺, YFP⁺tdTomato⁺, and YFP⁺tdTomato^neg cells from whole spleens. (B) Representative flow cytometry diagrams showing CD11b and Ly6C expression or F4/80 and Vcam1 expression in the indicated populations of labeled cells. (C) Percent Ly6C^hi monocytes, Ly6C^lo monocytes, pre-RPMs, and PRMs in YFP^negtdTomato⁺ (left), YFP⁺tdTomato⁺ (middle), and YFP⁺tdTomato^neg (right) cells. (D) Percent of F4/80⁺Vcam-1⁺ cells in YFP^negtdTomato⁺, YFP⁺ tdTomato⁺, and YFP⁺tdTomato^neg cells. (E-G) Characterization of monocyte and macrophage subpopulations in YFP^negtdTomato⁺, YFP⁺tdTomato⁺, and YFP⁺tdTomato^neg EBIs. (E) Representative flow cytometry diagrams of showing CD11b and Ly6C expression or F4/80 expression in the indicated populations of labeled cells in recipient-derived Ter119⁺ EBIs. (F) Percent Ly6C^hi monocytes, Ly6C^lo monocytes, pre-RPMs, and PRMs in YFP^negtdTomato⁺ (left), YFP⁺ tdTomato⁺ (middle), and YFP⁺tdTomato^neg (right) EBIs. (G) Percent of F4/80⁺ cells in YFP^negtdTomato⁺, YFP⁺ tdTomato⁺, and YFP⁺tdTomato^neg EBIs. Bars are representative of mean ± SEM.