| First Author | Cui G | Year | 2014 |
| Journal | Proc Natl Acad Sci U S A | Volume | 111 |
| Issue | 5 | Pages | 1915-20 |
| PubMed ID | 24449915 | Mgi Jnum | J:206571 |
| Mgi Id | MGI:5551514 | Doi | 10.1073/pnas.1318281111 |
| Citation | Cui G, et al. (2014) Characterization of the IL-15 niche in primary and secondary lymphoid organs in vivo. Proc Natl Acad Sci U S A 111(5):1915-20 |
| abstractText | IL-15 is a cytokine critical for development, maintenance, and response of T cells, natural killer (NK) cells, NK T cells, and dendritic cells. However, the identity and distribution of IL-15-expressing cells in lymphoid organs are not well understood. To address these questions, we established and analyzed IL-15-CFP knock-in mice. We found that IL-15 was highly expressed in thymic medulla, and medullary thymic epithelial cells with high MHC class II expression were the major source of IL-15. In bone marrow, IL-15 was detected primarily in VCAM-1(+)PDGFRbeta(+)CD31(-)Sca-1(-) stromal cells, which corresponded to previously described CXCL12-abundant reticular cells. In lymph nodes, IL-15-expressing cells were mainly distributed in the T-cell zone and medulla. IL-15 was expressed in some fibroblastic reticular cells and gp38(-)CD31(-) double-negative stromal cells in the T-cell zone. Blood endothelial cells, including all high endothelial venules, also expressed high IL-15 levels in lymph nodes, whereas lymphatic endothelial cells (LECs) lacked IL-15 expression. In spleen, IL-15 was expressed in VCAM-1(+) stromal cells, where its expression increased as mice aged. Finally, IL-15 expression in blood and LECs of peripheral lymphoid organs significantly increased in LPS-induced inflammation. Overall, we have identified and characterized several IL-15-expressing cells in primary and secondary lymphoid organs, providing a unique perspective of IL-15 niche in immune microenvironment. This study also suggests that some stromal cells express IL-7 and IL-15 differentially and suggests a way to functionally classify different stromal cell subsets. |
