Sunlight offers surprise benefit—it energizes infection fighting T cells

December 20, 2016
Credit: Georgetown University

Sunlight allows us to make vitamin D, credited with healthier living, but a surprise research finding could reveal another powerful benefit of getting some sun.

Georgetown University Medical Center researchers have found that , through a mechanism separate than vitamin D production, energizes T cells that play a central role in human immunity.

Their findings, published today in Scientific Reports, suggest how the skin, the body's largest organ, stays alert to the many microbes that can nest there.

"We all know sunlight provides vitamin D, which is suggested to have an impact on immunity, among other things. But what we found is a completely separate role of sunlight on immunity," says the study's senior investigator, Gerard Ahern, PhD, associate professor in the Georgetown's Department of Pharmacology and Physiology. "Some of the roles attributed to vitamin D on immunity may be due to this new mechanism."

They specifically found that low levels of , found in sun rays, makes T cells move faster—marking the first reported human cell responding to sunlight by speeding its pace.

"T cells, whether they are helper or killer, need to move to do their work, which is to get to the site of an infection and orchestrate a response," Ahern says. "This study shows that sunlight directly activates key immune cells by increasing their movement."

Ahern also added that while production of vitamin D required UV light, which can promote skin cancer and melanoma, blue light from the sun, as well as from special lamps, is safer.

And while the human and T cells they studied in the laboratory were not specifically skin T cells—they were isolated from mouse cell culture and from human blood—the skin has a large share of T cells in humans, he says, approximately twice the number circulating in the blood.

"We know that blue light can reach the dermis, the second layer of the skin, and that those T cells can move throughout the body," he says.

The researchers further decoded how blue light makes T cells move more by tracing the molecular pathway activated by the light.

What drove the motility response in T cells was synthesis of , which then activated a signaling pathway that increases T cell movement. Hydrogen peroxide is a compound that release when they sense an infection in order to kill bacteria and to "call" T cells and other immune cells to mount an immune response.

"We found that sunlight makes hydrogen peroxide in T cells, which makes the cells move. And we know that an also uses hydrogen peroxide to make T move to the damage," Ahern says. "This all fits together."

Ahern says there is much work to do to understand the impact of these findings, but he suggests that if blue light T cell activation has only beneficial responses, it might make sense to offer patients blue light therapy to boost their immunity.

Explore further: Low vitamin D levels linked to increased risk of bladder cancer

More information: Scientific Reports, www.nature.com/articles/srep39479

Related Stories

Low vitamin D levels linked to increased risk of bladder cancer

November 8, 2016
Vitamin D deficiency is associated with an increased risk of developing bladder cancer, according to a systematic review of seven studies presented today at the Society for Endocrinology annual conference in Brighton. Though ...

Scientists successfully create blood from skin cells

November 21, 2016
Researchers in Singapore have artificially generated new mouse blood and immune cells from skin cells. This is a significant first step towards the eventual goal: the engineering of new human blood cells from skin cells or ...

Cells discovered in mouse embryos could shed light on newborn skin immunity

April 20, 2016
A group of cells identified by A*STAR researchers may explain how a newborn baby's vulnerable skin defends against attacks to the immune system at first contact with the environment. In mice, these cells appear in a developing ...

Battle hymns and lullabies: Scientist sheds light on the T cell orchestra

October 27, 2016
In research published in the prestigious journal Immunity, a Saint Louis University researcher reports new findings that help understand how the immune system's dendritic cells direct other immune cells called T lymphocytes ...

Red ginseng, vitamin C may increase immune cell activity

March 3, 2016
(HealthDay)—Red ginseng and vitamin C enhance immune cell activation and suppress viral infection in mice, according to an experimental study published online Feb. 21 in the Journal of Pharmacy and Pharmacology.

Sunlight and vitamin D findings may help understanding of autoimmune diseases

July 18, 2012
(Medical Xpress) -- Aberdeen scientists have demonstrated for the first time a clear link between sunlight, vitamin D and an impact on regulatory cells in the immune system in findings that might provide new insights into ...

Recommended for you

Australian researchers in peanut allergy breakthrough

August 17, 2017
Australian researchers have reported a major breakthrough in the relief of deadly peanut allergy with the discovery of a long-lasting treatment they say offers hope that a cure will soon be possible.

Genetic variants found to play key role in human immune system

August 16, 2017
It is widely recognized that people respond differently to infections. This can partially be explained by genetics, shows a new study published today in Nature Communications by an international collaboration of researchers ...

Study identifies a new way to prevent a deadly fungal infection spreading to the brain

August 16, 2017
Research led by the University of Birmingham has discovered a way to stop a deadly fungus from 'hijacking' the body's immune system and spreading to the brain.

Biophysics explains how immune cells kill bacteria

August 16, 2017
(Tokyo, August 16) A new data analysis technique, moving subtrajectory analysis, designed by researchers at Tokyo Institute of Technology, defines the dynamics and kinetics of key molecules in the immune response to an infection. ...

How a nutrient, glutamine, can control gene programs in cells

August 15, 2017
The 200 different types of cells in the body all start with the same DNA genome. To differentiate into families of bone cells, muscle cells, blood cells, neurons and the rest, differing gene programs have to be turned on ...

Scientists identify gene that controls immune response to chronic viral infections

August 15, 2017
For nearly 20 years, Tatyana Golovkina, PhD, a microbiologist, geneticist and immunologist at the University of Chicago, has been working on a particularly thorny problem: Why are some people and animals able to fend off ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.