Fig. 2: Characteristics of Il15-expressing stromal cells in the BM.

A Flow cytometry staining of in Il15^GFP+/+ mice (green) or WT controls (grey histograms) pre-gated on CD45⁻CD31⁻Lin⁻(TER-119/CD71) showing a high amount of LepR⁺VCAM-1⁺ MSCs expressing GFP (n = 6, 16 from six independent experiments). B Cxcl12^DsRed+/wt Il15^GFP+/+ double reporter mice show a high co-expression of Il15 and Cxcl12 in CD45⁻CD31⁻Lin⁻(TER-119/CD71) stromal cells. Representative flow cytometry plots (left) and relative quantification of IL15-GFP expression among total Cxcl12-DsRed⁺ cells (right); n = 4 per group from four independent experiments. C Representative flow cytometry plot of CD200⁺CD24⁺ (pre)hypertrophic chondrocytes and CD200⁻CD24⁺ proliferating chondrocytes, pre-gated on CD45⁻Lin⁻ (TER-119/CD71/CD19/CD31), and quantification of GFP-expressing cells in Il15^GFP+/+ mice (green) or WT controls (grey) (n = 5, 10 from 5 independent experiments). D Representative flow cytometry plot of ECs pre-gated on CD31^hiCD144⁺CD45⁻Lin⁻ (Ter119/CD71), showing Il15^GFP expression in Sca-1^hi ICAM-1⁻ arteriolar ECs and Sca-1⁺ ICAM-1⁺ sinusoidal ECs of Il15^GFP+/+ mice (green) or WT controls (grey) (n = 6, 16 from 6 independent experiments). E Characterization of CD45⁻CD31⁻Lin⁻(TER-119/CD71) stromal cells in Il15^GFP+/+ mice: representative histograms (left) of the indicated markers in the GFP⁺ versus GFP⁻ stromal population, and summary dot plot across all experiments showing percent gated as positive (dot size) and the z-score of the median fluorescence intensity for each marker (right). Bar graphs show mean ± SEM with each dot representing a biological replicate. Numbers above the dot plots indicate P values from unpaired two-tailed Student’s t tests. ***P < 0.001, ****P < 0.0001.