Immune cells travel to protect the outer layers of the skin in response to sunlight-induced vitamin D, according to an article in the March 2007 issue of Nature Immunology.
The immune cells express enzymes that convert an inactive form of vitamin D -- which is synthesized by skin cells upon sun exposure -- to an active form that triggers expression of certain 'homing receptors' on the surface of effector T cells. These receptors, in turn, can draw T cells to the skin surface where they participate in immune surveillance and maintain barrier function. The new research suggests brief periods in the sun, to generate the precursor form of active vitamin D, can be beneficial by eliciting immune cells to skin tissues where they can ward off potential opportunistic pathogens and to help repair ultraviolet light-induced damage.
Eugene Butcher (Stanford University School of Medicine, Stanford, CA, USA)
Abstract available online.
(C) Nature Immunology press release.
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