Researchers have identified the cells that provide an essential survival factor to newly created immune cells according a report published online in Nature Immunology.
White blood cells known as T lymphocytes are born in the thymus and these cells are required to fight off viral and other infections. Upon leaving the thymus these cells prowl throughout the body seeking out potential foreign agents; however, the survival of these cells depends on periodic visits to lymph nodes, where they can 'recharge' by receiving a chemical signal called interleukin 7 (IL-7).
It was known for many years that IL-7 provides 'survival' signals to these naive T cells, but what actually produced IL-7 proved elusive. Sanjiv Luther and colleagues identify specialized 'fibroblastic reticular cells' found in lymph nodes and spleen as the source of IL-7. These cells make chemical signals that direct T cells to them and supply the essential IL-7 that prevents T cells from dying, thereby allowing them to continue to recirculate throughout the body searching for enemies.
Sanjiv Luther (University of Lausanne, Epalinges, Switzerland)
Abstract available online.
(C) Nature Immunology press release.
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