Vitamin D Activates T Cells

Vitamin D has been garnering attention from medical scientists for many functions besides promoting strong bones. A recent study shows why it is crucial for the function of the immune system. Danish researchers have found that killer T cells, a critical part of the immune response, use a vitamin D receptor to activate the cell. Without adequate vitamin D, the killer T cell will not become activated and will be unable to fight off germs. The body makes vitamin D when skin is exposed to sunlight, but epidemiologists estimate that approximately half the population is low in vitamin D because too little time is spent outside. The investigators believe that a better understanding of the role of this vitamin in the immune system will help develop vaccines and ways to counteract autoimmune diseases and transplant rejection.
[Nature Immunology, online March 7, 2010]