Francis Crick Institute and King’s College London collaborate to identify specialist cells which protect DNA

Researchers at the Francis Crick Institute and King’s College London have identified how specialist immune cells–called gamma delta (γδ T cells) T cells–assess the health of surface tissues and even protect against cancer-causing DNA damage.

The study, published in Nature Immunology, highlights the unique properties of these immune cells.

T cells are present in the blood and lymph nodes and become active when they recognise a specific target or threat, usually from a foreign infectious agent. γδ T cells exist within epithelial tissues, like the skin and gut lining, and survey the body’s own cells for any signs of damage or disease.

The research team examined the interactions occurring between skin γδ T cells and the cells that form the structure of mouse skin. They found that, while most normal T cells would recognise proteins derived from viruses or bacteria, γδ T cells sense a molecule called Skint1, which is displayed by healthy skin cells. This means that skin yδ T cells are actively monitoring and interacting with their surroundings in the absence of any obvious threat.

The team then exposed the skin to common forms of stress, including UV radiation and irritating chemicals and found that when y T cells were not able to see Skint1, they also weren’t able to discern these environmental challenges and help the skin recover.

The findings demonstrate that immune cell interactions with normal tissues can be key to mounting an effective response against subsequent damage or infection.

Duncan McKenzie, lead researcher and postdoctoral training fellow in the Crick’s Immunosurveillance Laboratory, said: “In order to sense disruption, these cells need to know what’s normal for the tissue. Like security guards, they stay familiar with their surroundings so that they can most effectively identify when things go wrong.

“Although we’ve specifically looked at interactions in mouse skin, we know that there are molecules similar to Skint1 in different tissues, including the human gut lining, where many γδ T cells are found. Our findings may therefore help to explain how γδ T cells maintain and protect many different parts of the human body.”

The research team continues to keep an eye on how yδT cells respond to tissue damage and dysregulation.