A master gene that helps mobilise the immune system to fight disease has been discovered by UK scientists.
It causes stem cells in the blood to become disease-fighting "Natural Killer" (NK) immune cells.
It is hoped the discovery will lead to new ways to boost the body's production of these frontline cells - potentially creating a new way to kill cancer.
The Nature Immunology study may also help development of new treatments for type 1 diabetes and multiple sclerosis.
These conditions are caused by a malfunctioning immune system turning against the body's own tissues, and it is suspected that faulty NK cells play a key role in this process.
The researchers, from Imperial College London, University College London and the Medical Research Council's National Institute for Medical Research have created mice that lack the key gene - E4bp4.