These guardian immune cells, called Adipose Type One Innate Lymphoid Cells, or ILCs, were only recently discovered by Professor Lynch and her team. They live in our fat, and are charged with maintaining a delicate balance of our immune systems.
Professor Lynch said: “All people have fat, even if they are not obese. Fat is found around almost all tissues in our body, and all fat has its own immune system, which we are only recently learning about.
“We have revealed that ILCs keep other immune cells called macrophages in check, by killing them based on certain physiological conditions in the body – they essentially guard against inflammation when macrophages are too numerous in fat. This function is unique as immune cells are not generally supposed to kill other healthy immune cells in non-pathological conditions.”
In other cases, ‘natural killer’ cells-which are part of the ILC family-recognise specific proteins on the surfaces of healthy immune cells that act a little like passwords; if a cell possesses the password, the natural killer cells let it go about its normal business.
Natural killer cells typically kill cancer cells, which lack the required password, whereas the healthy immune cells don’t. However, uniquely in fat, the ILCs do not recognise these passwords and instead attack the healthy macrophages.