Fig. 3: Deletion of Il15 in Prrx1⁺ stromal cells impairs NK cell development and CD8⁺ T_CM cells in the BM.

A Pathway of NK cell and ILC development in the mouse BM. Created in BioRender. Lab Account, D. (2025) https://BioRender.com/wf09zk2. B Relative abundance (top) and cell numbers (bottom) of the indicated cell types in the BM of Il15^flox/flox and Il15^flox/flox Prx1-Cre littermates. Shown are LSK, CLP, NKP and NKP, which co-expressed NKG2D, stage A iNK cells, stage B/C iNK cells and CD49b⁺ mNK cells (n = 4–11 from 2–3 independent experiments). C Representative flow cytometry plots showing rNKP and NKG2D⁺ rNKP in the BM of an Il15^flox/flox and an Il15^flox/flox Prx1-Cre littermate. D Representative flow cytometry plots showing stage A iNK cells in the BM of Il15^flox/flox and Il15^flox/flox Prx1-Cre littermate. E Relative abundance (top) and cell numbers (bottom) of CD8⁺ T_CM cells, CD69-expressing CD8⁺ T_RM cells, NKT cells and iILC1 in the BM of Il15^flox/flox and Il15^flox/flox Prx1-Cre littermates (n = 11–15 from four independent experiments). F Representative flow cytometry plots showing CD8⁺ T_CM cells in the BM of Il15^flox/flox and Il15^flox/flox Prx1-Cre littermate. G Experimental workflow of NK depletion using anti-NK1.1 antibodies and representative flow cytometry plots of NK cell depletion verification in the BM pre-gated on CD45⁺CD3⁻ cells and identified via CD49b and NKG2D (top). Relative quantification and absolute cell numbers of rNKPs in the BM of Il15^flox/flox (WT) and Il15^flox/flox Prx1-Cre littermates (Cre) after NK cell depletion (bottom); n = 4–6 from two independent experiments. All dot plots 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 < 0.05, **P < 0.01.