Stem Cell Colonies Develop After Signaling by Killer T-Cells to Niche Cells
"Nine blood stem cell colonies are illustrated in the image, which have developed into differentiated cell types, particularly into white blood cells (leukocytes).") (Photo courtesy of the Department of Clinical Research of the University of Bern, Tumor-Immunology Research Group)
Stem cell niches. Researchers know in general that niches are important places in bone marrow, and are where stem cells wait, surrounded by specialized niche cells. In general, the stem cells wait for calls to action. The calls to action arise through interactions among various proteins and other messengers that provide messages intended to stimulate a particular activity. Thus, the overall process is that when an infection occurs, the body fights back by creating more infection fighting cells. But exactly how are those messages sent and received?
New work at the University of Bern has uncovered more of the specifics. The so-called killer T-cells serve double duty – they flow through the blood looking for invaders to attack, and they travel to the bone marrow niches to signal niche cells to ask the stem cells to turn into white blood cells (leukocytes) that evolve and fight infections.
The researchers’ goals are at least two-fold. One is to better understand the immune system processes that fight off infections and other low-grade diseases. Another goal is to understand how this process becomes corrupt, and how that intersects with the development of leukemias.
Christian M. Schürch, Carsten Riether, Adrian F. Ochsenbein. Cytotoxic CD8 T Cells Stimulate Hematopoietic Progenitors by Promoting Cytokine Release from Bone Marrow Mesenchymal Stromal Cells. Cell Stem Cell, 2014; DOI: 10.1016/j.stem.2014.01.002