Figure 1. Comparison of the influence of BM niche age on differentiation profile of T-lineage vs. myeloid lineage choice. (A) Schematic workflow of the BM-niche age influence assay. (B) A representative flow cytometry analysis shows donor congenic marker gates (left panels), and profiles of T-lineage (Thy1.2+) vs. myeloid-lineage (Mac1+) cells derived from old (18 months old) and young (2 months old) IL7R−/− host BM niches after culture on OP9-DL1 stromal cell monolayer (right panels). These cells were originally from the same pool of young WT BM progenitors. (C) A summary of panel B in % myeloid-lineage cells (left) and % T-lineage cells (right) derived from old (striped bar) and young (grey bar) IL7R−/− host BM niches. Data show Mean ± SEM in all bar graphs, n = IL7R−/− host mouse number. (D) A representative culture result of Panel A shows absolute cell numbers (Mean ± SD) of myeloid cells vs. T-lineage cells derived from old or young IL7R−/− host BM niche-modulated young WT donor BM progenitors (~2000 sorted LSK cells loaded per well) after 14 days in culture on OP9-DL1 stromal cell monolayer (n = IL7R−/− host animal #).